WO2015009041A1 - 적응적 휘도 보상을 위한 인터 레이어 비디오 부호화 방법 및 그 장치, 비디오 복호화 방법 및 그 장치 - Google Patents
적응적 휘도 보상을 위한 인터 레이어 비디오 부호화 방법 및 그 장치, 비디오 복호화 방법 및 그 장치 Download PDFInfo
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- WO2015009041A1 WO2015009041A1 PCT/KR2014/006409 KR2014006409W WO2015009041A1 WO 2015009041 A1 WO2015009041 A1 WO 2015009041A1 KR 2014006409 W KR2014006409 W KR 2014006409W WO 2015009041 A1 WO2015009041 A1 WO 2015009041A1
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- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/30—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
- H04N19/33—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability in the spatial domain
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- H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
- H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
- H04N19/103—Selection of coding mode or of prediction mode
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- H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
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- H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
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- H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
- H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
- H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
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- H04N19/186—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a colour or a chrominance component
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- H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
- H04N19/187—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a scalable video layer
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Definitions
- the present invention relates to an interlayer video encoding method and a decoding method. More specifically, the present invention relates to a method for adaptively compensating for a luminance difference between interlayer images.
- video codec for efficiently encoding or decoding high resolution or high definition video content.
- video is encoded according to a limited encoding method based on coding units having a tree structure.
- Image data in the spatial domain is transformed into coefficients in the frequency domain using frequency transformation.
- the video codec divides an image into blocks having a predetermined size for fast operation of frequency conversion, performs DCT conversion for each block, and encodes frequency coefficients in units of blocks. Compared to the image data of the spatial domain, the coefficients of the frequency domain are easily compressed. In particular, since the image pixel value of the spatial domain is expressed as a prediction error through inter prediction or intra prediction of the video codec, when frequency conversion is performed on the prediction error, much data may be converted to zero.
- the video codec reduces data volume by substituting data repeatedly generated continuously with small size data.
- the multilayer video codec encodes and decodes a first layer video and one or more second layer videos.
- the multilayer video codec may compress data of the first layer video and the second layer video by using a method of removing temporal / spatial redundancy of the first layer video and the second layer video and redundancy between layers.
- each camera may not be calibrated to have the same physical characteristics, so a slight difference may occur for each image signal.
- Such a characteristic may reduce correlation between video of each layer, making it difficult to obtain an accurate disparity vector when encoding images obtained from layers of adjacent viewpoints, and reduce the compression efficiency by increasing the DC component of the residual signal. have.
- the present invention provides a method and apparatus for reducing the amount of computation for performing luminance compensation on a block in encoding a layer video, and using the reference block even when the reference block deviates from the boundary of the reference picture.
- the present invention also provides a computer-readable recording medium having recorded thereon a program for executing the method on a computer.
- the technical problem to be achieved by the present embodiment is not limited to the technical problem as described above, and other technical problems may be inferred from the following embodiments.
- the determining of the luminance compensation parameter for the selected luminance compensation model includes: color component of the second layer current block, type information of a picture including the second layer current block, and prediction mode of the second layer current block. The determination may be based on at least one of the above.
- a first layer decoder which reconstructs a first layer image based on encoding information obtained from a first layer bitstream
- Second layer decoding for reconstructing the second layer current block using the first layer reference block corresponding to the current block of the second layer to be reconstructed from the interlayer prediction information obtained from the second layer bitstream and the first layer reconstructed image part
- a luminance compensation determiner configured to select a luminance compensation model to be applied to the first layer reference block and to determine a luminance compensation parameter for the selected luminance compensation model
- the luminance compensation determiner may include the luminance compensation parameter based on at least one of color components of the second layer current block, type information of a picture including the second layer current block, and a prediction mode of the second layer current block. To determine,
- the second layer decoder may compensate for the luminance of the first layer reference block by using the luminance compensation parameter and reconstruct a second layer image including the second layer current block.
- the luminance compensation is adaptively performed to reduce the amount of computation required, and the reference block outside the boundary of the reference layer image may be used to improve encoding or decoding efficiency of the multilayer video.
- FIG. 1A is a block diagram of an interlayer video encoding apparatus, according to various embodiments.
- FIG. 1B is a flowchart of an interlayer video encoding method, according to various embodiments.
- FIG. 2A is a block diagram of an interlayer video decoding apparatus, according to various embodiments.
- 2B is a flowchart of an interlayer video decoding method, according to various embodiments.
- FIG 3 illustrates an interlayer prediction structure, according to an embodiment.
- FIG. 4 illustrates a method of calculating a luminance compensation parameter by the luminance compensation determiner of the interlayer video decoding apparatus, according to an exemplary embodiment.
- 5A is a flowchart of an operation of selecting, by a luminance compensation determiner, a luminance compensation model and determining a luminance compensation parameter, according to an exemplary embodiment.
- 5B is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter, according to an embodiment.
- 5C is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter, according to an embodiment.
- 5D is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter according to an embodiment.
- 5E is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter according to an embodiment.
- FIG. 6 illustrates a method of determining a luminance compensation parameter according to an embodiment.
- FIG. 7 is a block diagram of a video encoding apparatus 100 based on coding units having a tree structure, according to an embodiment of the present invention.
- FIG. 8 is a block diagram of a video decoding apparatus 200 based on coding units having a tree structure, according to various embodiments.
- FIG 9 illustrates a concept of coding units, according to various embodiments.
- FIG. 10 is a block diagram of an image encoder 400 based on coding units, according to various embodiments.
- FIG. 11 is a block diagram of an image decoder 500 based on coding units, according to various embodiments.
- FIG. 12 is a diagram illustrating deeper coding units according to depths, and partitions, according to various embodiments.
- FIG. 13 illustrates a relationship between a coding unit and transformation units, according to various embodiments.
- FIG. 14 is a diagram of deeper encoding information according to depths, according to various embodiments.
- 15 is a diagram of deeper coding units according to depths, according to various embodiments.
- 16, 17, and 18 illustrate a relationship between coding units, prediction units, and transformation units, according to various embodiments.
- FIG. 19 illustrates a relationship between a coding unit, a prediction unit, and a transformation unit, according to encoding mode information of Table 1.
- FIG. 20 illustrates a physical structure of a disk 26000 in which a program is stored, according to various embodiments.
- 21 shows a disc drive 26800 for recording and reading a program using the disc 26000.
- FIG. 22 illustrates the overall structure of a content supply system 11000 for providing a content distribution service.
- FIG. 23 illustrates an external structure of the mobile phone 12500 to which the video encoding method and the video decoding method of the present invention are applied, according to various embodiments.
- 25 is a diagram illustrating a digital broadcasting system employing a communication system, according to various embodiments.
- 26 is a diagram illustrating a network structure of a cloud computing system using a video encoding apparatus and a video decoding apparatus, according to various embodiments.
- the present invention provides a method and apparatus for performing adaptive luminance compensation in inter-layer video encoding or decoding. As the method and apparatus, encoding and decoding performance can be improved.
- the solution of the present invention is implemented as follows.
- the determining of the luminance compensation parameter for the selected luminance compensation model includes: color component of the second layer current block, type information of a picture including the second layer current block, and prediction mode of the second layer current block. The determination may be based on at least one of the above.
- a first luminance compensation model that determines a scale factor and a first offset, and adds the offset to a result of multiplying each pixel value of the first layer reference block by the scale factor to compensate for the luminance of the first layer reference block;
- Selecting the first luminance compensation model when the color component of the second layer current block is luma, and selecting the second luminance compensation model when the color component of the second layer current block is chroma It may be characterized in that it comprises a.
- the first luminance compensation model is selected; and if the second layer current block is a block inside a depth map picture, the second luminance compensation model It may be characterized in that it comprises the step of selecting.
- the prediction mode of the second layer current block is not a view synthesis prediction mode
- the first luminance compensation model is selected; and if the prediction mode of the second layer current block is a view synthesis prediction mode, And selecting the luminance compensation model.
- any one of a condition in which a color component of a second layer current block is a chromile condition, a condition in which the second layer current block is a block in a depth map picture, and a condition in which the prediction mode of the second layer current block is a view synthesis prediction mode If satisfied, select the second luminance compensation model,
- the determining of the luminance compensation parameter may include, when the first layer reference block is out of the boundary of the first layer reconstruction image, the out of area and the surrounding pixels of the out of the area exist within the boundary of the first layer reconstruction image. And replacing with pixels.
- the substituting may include padding by substituting a pixel value existing at a boundary of the first layer image from a boundary of the first layer reconstructed image to an outside of the boundary of the first layer reference block. have.
- the determining of the luminance compensation parameter for the selected luminance compensation model includes: color component of the second layer current block, type information of a picture including the second layer current block, and prediction mode of the second layer current block. The determination may be based on at least one of the above.
- a first luminance compensation model that determines a scale factor and a first offset and adds the offset to a result of multiplying each pixel value of a second layer current block by the scale factor to compensate for the luminance of the second layer current block or
- If it does not correspond to any of the above conditions may include selecting a first luminance compensation model.
- the determining of the luminance compensation parameter may include, when the first layer reference block is out of the boundary of the first layer reconstruction image, the out of area and the surrounding pixels of the out of the area exist within the boundary of the first layer reconstruction image. And replacing with pixels.
- a first layer decoder which reconstructs a first layer image based on encoding information obtained from a first layer bitstream
- Second layer decoding for reconstructing the second layer current block using the first layer reference block corresponding to the current block of the second layer to be reconstructed from the interlayer prediction information obtained from the second layer bitstream and the first layer reconstructed image part
- a luminance compensation determiner configured to select a luminance compensation model to be applied to the first layer reference block and to determine a luminance compensation parameter for the selected luminance compensation model
- the luminance compensation determiner may include the luminance compensation parameter based on at least one of color components of the second layer current block, type information of a picture including the second layer current block, and a prediction mode of the second layer current block. To determine,
- the second layer decoder may reconstruct a second layer image including the second layer current block by compensating the luminance of the first layer reference block by using the luminance compensation parameter.
- a first layer encoder configured to generate a first layer bitstream including encoding information generated by encoding the first layer image
- a second layer encoder to reconstruct a second layer current block reconstructed using a first layer reference block corresponding to a second layer current block to be reconstructed among the first layer reconstructed images to reconstruct the second layer current block;
- a luminance compensation determiner configured to select a luminance compensation model to be applied to the first layer reference block and to determine a luminance compensation parameter for the selected luminance compensation model
- the luminance compensation determiner may determine a luminance compensation parameter based on at least one of a color component of the second layer current block, type information of a picture including the second layer current block, and a prediction mode of the second layer current block. Decide,
- a second layer bitstream including inter layer prediction information between the first layer reference block and the second layer current block, which is luminance compensated using the luminance compensation parameter, may be generated.
- an interlayer video encoding technique and an interlayer video decoding technique in which luminance compensation is determined according to block characteristics, are proposed according to various embodiments.
- 7 to 19 a video encoding technique and a video decoding technique based on coding units having a tree structure according to various embodiments applicable to the interlayer video encoding technique and the decoding technique proposed above are disclosed.
- 20 to 26 various embodiments to which the video encoding method and the video decoding method proposed above are applicable are disclosed.
- the 'image' may be a still image of the video or a video, that is, the video itself.
- sample means data to be processed as data allocated to a sampling position of an image.
- the pixels in the spatial domain image may be samples.
- an interlayer video encoding apparatus an interlayer video encoding method, and an interlayer video decoding apparatus and an interlayer video decoding method are described with reference to FIGS. 1A to 7B.
- 1A is a block diagram of an interlayer video encoding apparatus 10 according to various embodiments.
- 1B is a flowchart of an interlayer video encoding method, according to various embodiments.
- the interlayer video encoding apparatus 10 includes a first layer encoder 12, a luminance compensation determiner 14, and a second layer encoder 16.
- the luminance compensation determiner 14 may be included in the second layer encoder 16. Although the luminance compensation determiner 14 may be located outside the second layer encoder 16, the luminance compensation determiner 14 is positioned inside the second layer encoder 16. Let's explain.
- the interlayer video encoding apparatus 10 classifies and encodes a plurality of image sequences for each layer according to a scalable video coding scheme, and includes a separate stream including data encoded for each layer. You can output The interlayer video encoding apparatus 10 may encode the first layer image sequence and the second layer image sequence into different layers.
- the first layer encoder 12 may encode the first layer images and output a first layer stream including encoded data of the first layer images.
- the second layer encoder 16 may encode second layer images and output a second layer stream including encoded data of the second layer images.
- low resolution images may be encoded as first layer images, and high resolution images may be encoded as second layer images.
- An encoding result of the first layer images may be output as a first layer stream, and an encoding result of the second layer images may be output as a second layer stream.
- a multiview video may be encoded according to a scalable video coding scheme.
- the center view images may be encoded as first layer images
- the left view images and right view images may be encoded as second layer images referring to the first layer image.
- the interlayer video encoding apparatus 10 allows three or more layers such as a first layer, a second layer, and a third layer
- the center view images are encoded as first layer images
- the left view images are second layer images.
- right-view images may be encoded as third layer images.
- the configuration is not necessarily limited to this configuration, and the layer in which the center view, the left view, and the right view images are encoded and the referenced layer may be changed.
- a scalable video coding scheme may be performed according to temporal hierarchical prediction based on temporal scalability.
- a first layer stream including encoding information generated by encoding images of a base frame rate may be output.
- Temporal levels may be classified according to frame rates, and each temporal layer may be encoded into each layer.
- the second layer stream including the encoding information of the high frame rate may be output by further encoding the high frame rate images by referring to the images of the base frame rate.
- scalable video coding may be performed on the first layer and the plurality of second layers.
- the first layer images, the first second layer images, the second second layer images, ..., and the K-th second layer images may be encoded. Accordingly, the encoding results of the first layer images are output to the first layer stream, and the encoding results of the first, second, ..., K-th second layer images are respectively the first, second, ..., K-th second layer. Can be output as a stream.
- the interlayer video encoding apparatus 10 may perform inter prediction to predict a current image by referring to images of a single layer. Through inter prediction, a motion vector representing motion information between the current picture and the reference picture and a residual component between the current picture and the reference picture may be generated.
- the interlayer video encoding apparatus 10 may perform inter-layer prediction for predicting second layer images by referring to the first layer images.
- one first layer image and a first layer image may be formed according to a multilayer prediction structure. Inter-layer prediction between three layer images and inter-layer prediction between a second layer image and a third layer image may be performed.
- a position difference component between the current image and a reference image of another layer and a residual component between the current image and a reference image of another layer may be generated.
- the interlayer prediction structure will be described in detail later with reference to FIG. 3.
- the interlayer video encoding apparatus 10 encodes each block of each image of the video for each layer.
- the type of block may be square or rectangular, and may be any geometric shape. It is not limited to data units of a certain size.
- the block may be a maximum coding unit, a coding unit, a prediction unit, a transformation unit, or the like among coding units having a tree structure.
- the maximum coding unit including the coding units of the tree structure may be variously represented as a coding block tree, a block tree, a root block tree, a coding tree, a coding root, or a tree trunk. It may be named.
- a video encoding and decoding method based on coding units having a tree structure will be described later with reference to FIGS. 8 to 20.
- Inter prediction and inter layer prediction may be performed based on a data unit of a coding unit, a prediction unit, or a transformation unit.
- the first layer encoder 12 may generate symbol data by performing source coding operations including inter prediction or intra prediction on the first layer images.
- the symbol data represents a sample value of each coding parameter and a sample value of the residual.
- the encoder 12 generates symbol data by performing inter prediction or intra prediction, transformation, and quantization on samples of a data unit of the first layer images, and performs entropy encoding on the symbol data.
- One layer stream can be created.
- the second layer encoder 16 may encode second layer images based on coding units having a tree structure.
- the second layer encoder 16 generates symbol data by performing inter / intra prediction, transformation, and quantization on samples of a coding unit of a second layer image, and performs entropy encoding on the symbol data, thereby performing a second layer. You can create a stream.
- the second layer encoder 16 may perform interlayer prediction for predicting the second layer image by using a reconstructed sample of the first layer image.
- the second layer encoder 16 generates a second layer prediction image by using the first layer reconstructed image to encode a second layer original image of the second layer image sequence through an interlayer prediction structure.
- a prediction error between the two-layer original image and the second layer prediction image may be encoded.
- the second layer encoder 16 may perform interlayer prediction on the second layer image for each block, such as a coding unit or a prediction unit.
- a block of the first layer image to be referred to by the block of the second layer image may be determined.
- a reconstruction block of the first layer image positioned corresponding to the position of the current block in the second layer image may be determined.
- the second layer encoder 16 may determine a second layer prediction block by using a first layer reconstruction block corresponding to the second layer block.
- the second layer encoder 16 may use the second layer prediction block determined by using the first layer reconstruction block according to the interlayer prediction structure as a reference image for interlayer prediction of the second layer original block.
- the second layer encoder 16 entropy encodes a residual component according to an inter-layer prediction, that is, an error between a sample value of a second layer prediction block and a sample value of a second layer original block by using the first layer reconstructed image. can do.
- the second layer encoder 16 may encode the current layer image sequence with reference to the first layer reconstructed images through the interlayer prediction structure.
- the second layer encoder 16 may encode the second layer image sequence according to a single layer prediction structure without referring to other layer samples. Therefore, care should be taken not to limit the interpretation that the second layer encoder 16 performs only inter-layer prediction in order to encode the second layer image sequence.
- the first layer encoder 12 encodes the first view video
- the second layer encoder 16 performs a second image.
- a viewpoint video may be encoded.
- the video for each viewpoint may be photographed by different cameras or acquired through different lenses. Since the photographing angle, illumination, or characteristics of an imaging tool (camera, lens, etc.) may be different for each viewpoint, luminance may not match between videos acquired for each viewpoint. This luminance mismatch phenomenon may be related to the difference in the sample value of the video for each view.
- the luminance compensation determiner 14 of the interlayer video encoding apparatus 10 may compensate and encode the luminance difference of the video for each viewpoint in view of the luminance mismatch between viewpoints. For example, the luminance difference between the first view image encoded by the first layer encoder 12 and the second view image encoded by the second layer encoder 16 may be encoded. Since the luminance difference of the second view image with respect to the first view image is encoded, luminance compensation may be performed when the second layer encoder 16 encodes the second view video.
- a predetermined parameter may be used to compensate for a luminance difference between the first layer block and the second layer block.
- the luminance compensation parameter for compensating for the luminance difference of each block unit is included in the bitstream and transmitted, or the peripheral pixel value of the second layer current block and the peripheral pixel value of the first layer reconstruction block corresponding to the current block are utilized. Can be determined. A method of determining the luminance compensation parameter will be described later with reference to FIG. 4.
- the luminance compensation determiner 14 may include a luminance compensation model and luminance compensation parameters used when performing luminance compensation in consideration of characteristics of each data unit, such as a slice or a block of a current image. It can be determined adaptively.
- FIG. 1B is a flowchart of an interlayer video encoding method, according to various embodiments.
- the first layer encoder 12 may encode the first layer image and generate a first layer bitstream including sample values of the generated encoding information.
- the second layer encoder 14 encodes the second layer image and generates a second layer bitstream including sample values of the generated encoding information, and determines a predetermined partition mode and a prediction mode. You can restore the two-layer current block. That is, the second layer encoder 14 reconstructs the second layer current block by using the first layer reference block corresponding to the second layer current block to be reconstructed among the first layer reconstruction images according to the predetermined partition mode and the prediction mode. can do.
- the interlayer video encoding apparatus 10 encodes a multiview video, it may be interpreted that the first layer image corresponds to the first viewpoint image and the second layer image corresponds to the second viewpoint image.
- the layer encoder 12 and the second layer encoder 16 may divide the image into blocks, and encode the blocks for each block.
- the luminance compensation determiner 14 compensates for the luminance based on one of a color component of the second layer current block, type information of a picture including the second layer current block, and a prediction mode of the second layer current block.
- the parameter can be determined.
- the second layer encoder 16 may generate a second layer bitstream including interlayer prediction information between the first layer reference block whose luminance is compensated using the determined luminance compensation parameter and the second layer current block. Can be generated.
- the second layer encoder 16 may include partition mode information, prediction mode information, and luminance compensation information.
- the second layer bitstream may be generated.
- the second layer encoder 16 since the second layer encoder 16 may perform interlayer prediction for encoding an error between the first layer image and the second layer image, the second layer encoder 16 may correspond to blocks (second layer blocks) of the second layer image. Residual components between reference blocks (first layer reference blocks) of the first layer image may be encoded. Therefore, the second layer bitstream may include various interlayer prediction information and interlayer residual components representing the interlayer encoding scheme.
- the second layer encoder 16 may determine partition mode information indicating the partition mode of the second layer block and determine prediction mode information indicating the prediction mode of the second layer block.
- the prediction mode information of the second layer block may be determined by merge or advanced motion vector prediction (AMVP).
- AMVP advanced motion vector prediction
- the second layer encoder 16 uses the first layer reference block corresponding to the second layer block to be reconstructed from the first layer reconstruction image according to the predetermined partition mode and the prediction mode. The second layer current block may be restored.
- the luminance compensation determiner 14 may determine the luminance compensation parameter applied to the first compensation layer and the luminance compensation parameter applied to the first layer block determined using the first layer reference block and the second layer current block. That is, the luminance compensation determiner 14 may determine the luminance compensation model and the luminance compensation parameter with respect to the first layer reference block.
- the second layer encoder 16 includes a second layer including interlayer prediction information between a first layer reference block and a second layer current block whose luminance is determined according to whether luminance compensation is performed according to the determined luminance compensation parameter.
- the layer bitstream may be generated.
- luminance compensation may be given priority in a specific encoding mode according to the encoding mode of the block.
- the interlayer video encoding apparatus 10 may include a central processor (not shown) that collectively controls the first layer encoder 12, the luminance compensation determiner 14, and the second layer encoder 16. ) May be included.
- the first layer encoder 12, the luminance compensation determiner 14, and the second layer encoder 16 may be operated by their own processors (not shown), and the processors (not shown) may be mutually organic.
- the interlayer video encoding apparatus 10 may operate as a whole.
- the first layer encoder 12, the luminance compensation determiner 14, and the second layer encoder 16 may be controlled by the control of an external processor (not shown) of the interlayer video encoding apparatus 10. It may be.
- the interlayer video encoding apparatus 10 may include one or more data storage units (not shown) that store input and output data of the first layer encoder 12, the luminance compensation determiner 14, and the second layer encoder 16. It may include.
- the interlayer video encoding apparatus 10 may include a memory controller (not shown) that controls data input / output of the data storage unit (not shown).
- the interlayer video encoding apparatus 10 may perform a video encoding operation including transformation by operating in conjunction with an internal video encoding processor or an external video encoding processor to output a video encoding result.
- the internal video encoding processor of the interlayer video encoding apparatus 10 may implement a video encoding operation as a separate processor.
- the inter-layer video encoding apparatus 10, the central computing unit, or the graphics processing unit may include a video encoding processing module to implement a basic video encoding operation.
- FIG. 2A is a block diagram of an interlayer video decoding apparatus, according to various embodiments.
- the interlayer video decoding apparatus 20 includes a first layer decoder 22, a luminance compensation determiner 24, and a second layer decoder 26.
- the luminance compensation determiner 24 may be included in the second layer decoder 26.
- the luminance compensation determiner 24 according to another exemplary embodiment may be located outside the second layer encoder 26.
- the interlayer video decoding apparatus 20 may receive bitstreams for each layer according to a scalable encoding method.
- the number of layers of the bitstreams received by the interlayer video decoding apparatus 20 is not limited.
- the first layer decoder 22 of the interlayer video decoding apparatus 20 receives and decodes the first layer stream, and the second layer decoder 26 decodes the second layer stream. An embodiment of receiving and decoding will be described in detail.
- the interlayer video decoding apparatus 20 may receive a stream in which image sequences having different resolutions are encoded in different layers.
- the low resolution image sequence may be reconstructed by decoding the first layer stream, and the high resolution image sequence may be reconstructed by decoding the second layer stream.
- a multiview video may be decoded according to a scalable video coding scheme.
- left view images may be reconstructed by decoding the first layer stream.
- Right-view images may be reconstructed by further decoding the second layer stream in addition to the first layer stream.
- the center view images may be reconstructed by decoding the first layer stream.
- Left view images may be reconstructed by further decoding a second layer stream in addition to the first layer stream.
- Right-view images may be reconstructed by further decoding the third layer stream in addition to the first layer stream.
- a scalable video coding scheme based on temporal scalability may be performed. Images of the base frame rate may be reconstructed by decoding the first layer stream. The high frame rate images may be reconstructed by further decoding the second layer stream in addition to the first layer stream.
- first layer images may be reconstructed from the first layer stream, and second layer images may be further reconstructed by further decoding the second layer stream with reference to the first layer reconstructed images.
- the K-th layer images may be further reconstructed by further decoding the K-th layer stream with reference to the second layer reconstruction image.
- the interlayer video decoding apparatus 20 obtains encoded data of first layer images and second layer images from a first layer stream and a second layer stream, and adds a motion vector and an interlayer generated by inter prediction.
- the prediction information generated by the prediction can be further obtained.
- the interlayer video decoding apparatus 20 may decode inter-predicted data for each layer and may decode inter-layer predicted data among a plurality of layers. Reconstruction through motion compensation and inter-layer decoding may be performed based on a coding unit or a prediction unit.
- images may be reconstructed by performing motion compensation for the current image with reference to reconstructed images predicted through inter prediction of the same layer.
- Motion compensation refers to an operation of reconstructing a reconstructed image of the current image by synthesizing the reference image determined using the motion vector of the current image and the residual component of the current image.
- interlayer video decoding apparatus 20 may perform interlayer decoding with reference to the first layer images in order to reconstruct a second layer image predicted through interlayer prediction.
- Inter-layer decoding refers to an operation of reconstructing a reconstructed image of the current image by synthesizing a reference image of another layer determined to predict the current image and a residual component of the current image.
- the interlayer video decoding apparatus 20 may perform interlayer decoding for reconstructing third layer images predicted with reference to the second layer images.
- the interlayer prediction structure will be described in detail later with reference to FIG. 3.
- the second layer decoder 26 may decode the second layer stream without referring to the first layer image sequence. Therefore, care should be taken not to limit the interpretation that the second layer decoder 26 performs inter-layer prediction in order to decode the second layer image sequence.
- the interlayer video decoding apparatus 20 decodes each block of each image of the video.
- the block may be a maximum coding unit, a coding unit, a prediction unit, a transformation unit, or the like among coding units having a tree structure.
- the first layer decoder 22 may decode the first layer image by using encoding symbols of the parsed first layer image. If the interlayer video decoding apparatus 20 receives streams encoded based on coding units having a tree structure, the first layer decoder 22 may select coding units having a tree structure for each maximum coding unit of the first layer stream. Decryption may be performed on a basis.
- the first layer decoder 22 may obtain encoded information and encoded data by performing entropy decoding for each largest coding unit.
- the first layer decoder 22 may reconstruct the residual component by performing inverse quantization and inverse transformation on the encoded data obtained from the stream.
- the first layer decoder 22 according to another embodiment may directly receive a bitstream of quantized transform coefficients. As a result of performing inverse quantization and inverse transformation on the quantized transform coefficients, the residual component of the images may be reconstructed.
- the first layer decoder 22 may reconstruct the first layer images by combining the prediction image and the residual component through motion compensation between the same layer images.
- the second layer decoder 26 may generate a second layer prediction image by using samples of the first layer reconstruction image.
- the second layer decoder 26 may decode the second layer stream to obtain a prediction error according to interlayer prediction.
- the second layer decoder 26 may generate the second layer reconstruction image by combining the prediction error with the second layer prediction image.
- the second layer decoder 26 may determine the second layer prediction image by using the first layer reconstructed image decoded by the first layer decoder 22.
- the second layer decoder 26 may determine a block of the first layer image to which a block such as a coding unit or a prediction unit of the second layer image refers, according to the interlayer prediction structure. For example, a reconstruction block of the first layer image positioned corresponding to the position of the current block in the second layer image may be determined.
- the second layer decoder 26 may determine the second layer prediction block by using the first layer reconstruction block corresponding to the second layer block.
- the second layer decoder 26 may use the second layer prediction block determined by using the first layer reconstruction block according to the interlayer prediction structure as a reference image for interlayer prediction of the second layer original block. In this case, the second layer decoder 26 may reconstruct the second layer block by synthesizing the sample value of the second layer prediction block determined using the first layer reconstructed image and the residual component according to the interlayer prediction. Can be.
- the second layer decoder 26 may reconstruct the first layer image. Can be interpolated to resize to the same resolution as the second layer original image.
- the interpolated first layer reconstruction image may be determined as a second layer prediction image for interlayer prediction.
- the first layer decoder 22 of the interlayer video decoding apparatus 20 decodes the first layer stream to reconstruct the first layer image sequence
- the second layer decoder 26 performs the second layer stream. It is possible to reconstruct the second layer image sequence by decoding.
- the luminance compensation determiner 24 of the interlayer video decoding apparatus 20 may compensate for and restore the luminance difference of the video for each viewpoint in view of the luminance mismatch between viewpoints. For example, a luminance difference between the first view image decoded by the first layer decoder 22 and the second view image decoded by the second layer decoder 26 may be obtained from the bitstream. Since the luminance difference of the second viewpoint image with respect to the first viewpoint image is obtained, when the second layer decoder 26 decodes the second viewpoint video, luminance compensation may be performed on the first layer image.
- the luminance compensation determiner 24 adaptively selects and selects a luminance compensation model used when performing luminance compensation in consideration of characteristics of each data unit such as a picture or a block of a current image. Luminance compensation parameters for the luminance compensation model may be determined.
- 2B is a flowchart of an interlayer video decoding method, according to various embodiments.
- the first layer decoder 22 may reconstruct the first layer image based on the encoding information obtained from the first layer bitstream.
- the second layer decoder 26 uses the first layer reference block corresponding to the second layer block in the first layer reconstructed image according to the interlayer prediction structure.
- the second layer reconstruction block may be determined.
- the second layer decoder 26 may perform the first layer reference block using the first layer reference block corresponding to the current block to be reconstructed in the second layer among the interlayer prediction information obtained from the second layer bitstream and the first layer reconstructed image.
- the partition mode and the prediction mode of the 2 layer current block can be determined.
- the luminance compensation determiner 24 selects a luminance compensation model based on one of a color component of a second layer current block, type information of a picture including a second layer current block, and a prediction mode of the current block.
- the luminance compensation parameter for the selected luminance compensation model may be determined.
- the second layer decoder 26 may compensate for the luminance of the first layer reference block by using the determined luminance compensation parameter and reconstruct a second layer image including the second layer current block.
- the information on the luminance difference between layers may be obtained from the bitstream.
- the information about the luminance difference between layers may be derived by using a peripheral pixel value of the second layer current block and a peripheral pixel value of the first layer reconstruction block corresponding to the current block.
- the luminance value of the first layer block may be compensated by the preset luminance.
- the luminance compensation determiner 24 may obtain partition mode information and prediction mode information of the second layer block from the second layer bitstream. According to an embodiment, the luminance compensation determiner 24 may select a luminance compensation model for the first layer block from the second layer bitstream and determine a luminance compensation parameter. For example, the prediction mode information of the second layer block may be determined by merge or advanced motion vector prediction (AMVP).
- AMVP advanced motion vector prediction
- the interlayer video decoding apparatus 20 may include a central processor (not shown) that collectively controls the first layer decoder 22, the luminance compensation determiner 24, and the second layer decoder 26. ) May be included.
- the first layer decoder 22, the luminance compensation determiner 24, and the second layer decoder 26 may be operated by their own processors (not shown), and the processors (not shown) may be mutually organic. As it operates, the interlayer video decoding apparatus 20 may operate as a whole.
- the first layer decoder 22, the luminance compensation determiner 24, and the second layer decoder ( 26 may be controlled.
- the interlayer video decoding apparatus 20 may store one or more data in which input and output data of the first layer decoder 22, the luminance compensation determiner 24, and the second layer decoder 26 are stored. It may include a portion (not shown).
- the interlayer video decoding apparatus 20 may include a memory controller (not shown) that controls data input / output of the data storage unit (not shown).
- the interlayer video decoding apparatus 20 may operate in conjunction with an internal video decoding processor or an external video decoding processor to restore video through video decoding, thereby performing a video decoding operation including an inverse transform. Can be done.
- the internal video decoding processor of the interlayer video decoding apparatus 20 may include not only a separate processor but also an interlayer video decoding apparatus 20, a central computing unit, and a graphic computing unit including a video decoding processing module. It may also include the case of implementing a basic video decoding operation.
- the interlayer video decoding apparatus 20 compensates for a luminance difference or an inter-view luminance difference between images of different layers with respect to a specific type of block or slice in a process of decoding a second layer image. Therefore, the luminance between the first layer reconstructed image and the second layer reconstructed image may be uniform.
- the interlayer video encoding apparatus 10 may reduce residual components between a predicted image and an original image by performing luminance compensation between images of different layers in a specific type of block or slice. Therefore, the coding efficiency can be increased.
- FIG 3 illustrates an interlayer prediction structure, according to an embodiment.
- the interlayer video encoding apparatus 10 predictively encodes base view images, left view images, and right view images according to a reproduction order 50 of the multiview video prediction structure shown in FIG. 3. Can be.
- images of the same view are arranged in the horizontal direction. Therefore, left view images labeled 'Left' are arranged in a row in the horizontal direction, basic view images labeled 'Center' are arranged in a row in the horizontal direction, and right view images labeled 'Right' are arranged in a row in the horizontal direction. It is becoming.
- the base view images may be center view images, in contrast to left / right view images.
- images having the same POC order are arranged in the vertical direction.
- the POC order of an image indicates a reproduction order of images constituting the video.
- 'POC X' displayed in the multi-view video prediction structure 40 indicates the relative playback order of the pictures located in the corresponding column. The smaller the number of X is, the higher the playback order is and the larger the playback order is, the slower the playback order is.
- the left view images denoted as 'Left' are arranged in the horizontal direction according to the POC order (playing sequence), and the base view image denoted as 'Center'. These images are arranged in the horizontal direction according to the POC order (playing order), and right-view images marked as 'Right' are arranged in the horizontal direction according to the POC order (playing order).
- both the left view image and the right view image located in the same column as the base view image are images having different viewpoints but having the same POC order (playing order).
- Each GOP includes images between successive anchor pictures and one anchor picture.
- An anchor picture is a random access point.
- the anchor picture When a video is played at random, when the playback position is randomly selected from among images arranged according to the playback order of the video, that is, the POC order, the anchor picture has the nearest POC order at the playback position. Is played.
- Base view images include base view anchor pictures 51, 52, 53, 54, and 55
- left view images include left view anchor pictures 151, 152, 153, 154, and 155, and right view point.
- the images include right-view anchor pictures 251, 252, 253, 254, and 255.
- Multi-view images may be played back in GOP order and predicted (restored).
- images included in GOP 0 may be reproduced, and then images included in GOP 1 may be reproduced. That is, images included in each GOP may be reproduced in the order of GOP 0, GOP 1, GOP 2, and GOP 3.
- the images included in GOP 1 may be predicted (restored). That is, images included in each GOP may be predicted (restored) in the order of GOP 0, GOP 1, GOP 2, and GOP 3.
- inter-view prediction inter layer prediction
- inter prediction inter prediction
- an image starting with an arrow is a reference image
- an image ending with an arrow is an image predicted using the reference image.
- the prediction result of the base view images may be encoded and output in the form of a base view image stream, and the prediction result of the additional view images may be encoded and output in the form of a layer bitstream.
- the prediction encoding result of the left view images may be output as the first layer bitstream, and the prediction encoding result of the right view images may be output as the second layer bitstream.
- B-picture type pictures are predicted with reference to an I-picture type anchor picture followed by a POC order and an I-picture type anchor picture following it.
- the b-picture type pictures are predicted by referring to an I-picture type anchor picture followed by a POC order and a subsequent B-picture type picture or by referring to a B-picture type picture followed by a POC order and an I-picture type anchor picture following it. .
- inter-view prediction (inter layer prediction) referring to different view images and inter prediction referring to the same view images are performed, respectively.
- inter-view prediction For left view anchor pictures 151, 152, 153, 154, and 155, inter-view prediction (inter layer prediction) with reference to the base view anchor pictures 51, 52, 53, 54, and 55 having the same POC order, respectively. This can be done.
- the base view images 51, 52, 53, 54, 55 having the same POC order or the left view anchor pictures 151, 152, 153 Inter-view prediction may be performed with reference to 154 and 155.
- reference inter-view prediction (inter layer prediction) may be performed.
- the remaining images other than the anchor pictures 151, 152, 153, 154, 155, 251, 252, 253, 254, and 255 of the left view images and the right view images are predicted with reference to the same view images.
- left view images and the right view images may not be predicted with reference to the anchor picture having the playback order that precedes the additional view images of the same view. That is, for inter prediction of the current left view image, left view images other than a left view anchor picture having a playback order preceding the current left view image may be referenced. Similarly, for inter prediction of a current right view point image, right view images except for a right view anchor picture whose reproduction order precedes the current right view point image may be referred to.
- the left view image that belongs to the previous GOP that precedes the current GOP to which the current left view image belongs is not referenced and is left view point that belongs to the current GOP but is reconstructed before the current left view image.
- the prediction is performed with reference to the image. The same applies to the right view image.
- the interlayer video decoding apparatus 20 may reconstruct base view images, left view images, and right view images according to the reproduction order 50 of the multiview video prediction structure illustrated in FIG. 3. have.
- Left view images may be reconstructed through inter-view disparity compensation referring to the base view images and inter-image motion compensation referring to the left view images.
- the right view images may be reconstructed through inter-view disparity compensation referring to the base view images and the left view images and inter-motion motion compensation referring to the right view images.
- Reference images must be reconstructed first for disparity compensation and motion compensation of left view images and right view images.
- the left-view images may be reconstructed through the inter-image motion compensation referring to the reconstructed left view reference image.
- right-view images may be reconstructed through inter-image motion compensation referring to the reconstructed right view reference image.
- the left view image belonging to the previous GOP that precedes the current GOP to which the current left view image belongs does not refer to, but is reconstructed before the current left view image. It is preferable that only the left view image is referred to. The same applies to the right view image.
- the interlayer video encoding apparatus 10 and the interlayer video decoding apparatus 20 may adaptively determine a luminance compensation parameter according to an image characteristic.
- the interlayer video encoding apparatus 10 and the interlayer video decoding apparatus 20 may select different luminance compensation models for each slice or block and different luminance compensation parameters according to the selected luminance compensation models.
- the present invention will be described with reference to FIGS. 4 and 5.
- FIG. 4 illustrates a method of calculating a luminance compensation parameter by the luminance compensation determiner of the interlayer video decoding apparatus, according to an exemplary embodiment.
- the luminance compensation for the first layer reference block 6100 is performed by using the first layer reference block 6500 and the second layer current block 6100 to calculate a luminance compensation model defined by Equation 1 below. It can be performed using.
- the luminance compensation determiner 24 may determine a scale factor (a) and an offset (b).
- the second layer decoder 26 performs luminance compensation on the result of multiplying each pixel value Pred (x, y) 6550 of the first layer reference block by the scale factor (a) and adding the offset (b).
- Luminance compensation may be performed by determining each pixel value Pred '(x, y) of the one-layer reference block.
- Scale factor a and offset b are called luminance compensation parameters.
- the luminance compensation model defined by Equation 1 is referred to as a first luminance compensation model.
- the luminance compensation determiner 24 focuses on the difference between the luminance of the pixels in the second layer current block and the luminance of the neighboring pixels of the current block. All or some of the NBref 6050 and NBcur 6170 may be used to calculate the luminance compensation parameters a and b. Since a and b may be determined using the neighboring pixels of the current block 6100 and the reference block 6500, the luminance compensation determiner may not be transmitted to the interlayer video decoding apparatus 20 through syntax. 24 may calculate luminance compensation parameters a and b. Therefore, the transmission data can be reduced.
- the methods for calculating the luminance compensation parameters a and b include a linear regression method, an average of difference based prediction (ADP) method, and a difference of average based prediction (DAP) method.
- ADP average of difference based prediction
- DAP difference of average based prediction
- the luminance compensation parameters a and b may be calculated using Equation 2 below.
- N is the number of neighboring pixels of the block (N in FIG. 4 is 32), NBcur is the neighboring pixel 6170 of the current block, and NBref is the neighboring pixel 6050 of the reference block.
- the encoding operation for predicting the luminance difference between the layers may increase the amount of computation.
- the second layer decoder 26 may generate a load when performing luminance compensation.
- the luminance compensation determiner 24 may consider performing luminance compensation by adding only an offset when performing luminance compensation in consideration of characteristics of each data unit such as a slice or a block of the current image. That is, the luminance compensation using only the offset may be performed using a luminance compensation model defined by Equation 3 below.
- the luminance compensation determiner 24 may determine only an offset (b ′).
- the second layer decoder 26 adds an offset b 'to each value Pred (x, y) of the first layer reference block 6550 to determine the luminance compensation of the first layer current block 6100.
- Each pixel value Pred '(x, y) may be determined. Since the luminance compensation model defined by Equation 3 is performed only by the operation of adding the offset without the multiplication operation, the amount of computation required to perform the luminance compensation may be reduced.
- the luminance compensation determiner 24 may be determined using an equation different from the equation for calculating the offset b in Equation 2 to determine the offset b ′ in the luminance compensation model defined by Equation 3.
- the luminance compensation model defined by Equation 3 is referred to as a second luminance compensation model.
- FIG. 4 an example of determining the luminance compensation model and the parameters constituting the model in the interlayer video decoding apparatus 20 has been described. However, a person skilled in the art will appreciate that the method described in FIG. It will be understood that the encoding apparatus 10 may also be performed.
- 5A is a flowchart of an operation of selecting, by a luminance compensation determiner, a luminance compensation model and determining a luminance compensation parameter, according to an exemplary embodiment.
- the luminance compensation determiner 24 of the interlayer video decoding apparatus 20 may determine the color component of the second layer current block to perform luminance compensation.
- the luminance compensation determiner 24 uses a luminance compensation model defined by Equation 1, that is, a scale factor (a) and an offset (b) if the color component of the second layer current block is luma.
- a luminance compensation model defined by Equation 1, that is, a scale factor (a) and an offset (b) if the color component of the second layer current block is luma.
- One luminance compensation model can be selected.
- the luminance compensation determiner 24 may determine the scale factor a and the offset b, which are luminance compensation parameters.
- the second layer decoder 26 uses the luminance compensation parameter determined by the luminance compensation determiner 24 to determine a scale factor (a) for each pixel value Pred (x, y) of the first layer reference block.
- the luminance compensation may be performed by determining each pixel value Pred '(x, y) of the luminance-compensated first layer reference block by adding the offset b to the multiplication result.
- the luminance compensation may be performed using the first luminance compensation model only for the luma component, and the luminance compensation may be performed using the second luminance compensation model for the chroma component. Accordingly, in operation 5070, if the color component of the second layer current block is chroma, the luminance compensation determiner 24 uses the luminance compensation model defined in Equation 3, that is, the second luminance compensation using only the offset b '. You can choose a model.
- the luminance compensation determiner 24 may determine an offset b ′, which is a luminance compensation parameter.
- the second layer decoder 26 offsets b 'to each pixel value Pred (x, y) of the first layer reference block by using the luminance compensation parameter determined by the luminance compensation determiner 24. ) May be determined by adding each value of each pixel value Pred '(x, y) of the luminance-compensated first layer reference block to perform luminance compensation.
- the method of selecting the luminance compensation model and determining the luminance compensation parameter according to the embodiment of FIG. 5A may be performed according to the pseudo code of Table 1 below.
- Table 1 H.8.5.2.2.5.2 Derivation process for illumination compensation parameters Inputs to this process are: a list curSampleList specifying the current samples,, a list refSampleList specifying the reference samples, a variable numSamples specifying the number of elements in curSampleList and refSampleList. a bit depth of samples, bitDepth.
- variable cIdx specifying color component index
- variable icOffset specifying a offset for illumination compensation
- variable icShift specifying a bit shift for illumination compensation.
- the variable icWeight is set equal to 1
- the variable icOffset is set equal to 0
- the variable icShift is set equal to 0.
- the variables sumRef, sumCur, sumRefSquare and sumProdRefCur are set equal to 0 and the following applies for i ranging from 0 to num
- psDenomDiv denomDiv >> psShiftDenom (H 193)
- variable divCoeff is derived from Table H 11 depending on psDenomDiv.
- the variable icShift specifying a bit shift for illumination compensation is set equal to 13.
- the variable icWeight specifying a weight for illumination compensation with 7 bit precision is derived as spec
- icWeight invPsIcWeight (H 198) Otherwise, (invPsIcWeight is less than -26 or greater than or equal to 26), the following applies.
- decIcShift Max (0, Floor (Log2 (Abs (icWeight))-5)) (H 199)
- icWeight invPsIcWeight >> decIcShift (H 200)
- icShift- decIcShift (H 201)
- 5B is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter according to an embodiment.
- the luminance compensation determiner 24 of the interlayer video decoding apparatus 20 checks type information of a picture including a current layer of a second layer to perform luminance compensation, and corresponds to a texture picture. It may be determined whether it corresponds to a depth map picture.
- the luminance compensation determiner 24 may select a first luminance compensation model, that is, a luminance compensation model using the scale factor (a) and the offset (b). have.
- the luminance compensation determiner 24 may determine the scale factor a and the offset b ′, which are luminance compensation parameters.
- the second layer decoder 26 uses the determined luminance compensation parameter to multiply each pixel value Pred (x, y) of the first layer reference block by the scale factor (a) to offset (b). ) May be determined by adding each value of each pixel value Pred '(x, y) of the luminance-compensated first layer reference block to perform luminance compensation.
- the luminance compensation determiner 24 may select a luminance compensation model using only the second luminance compensation model, that is, the offset b '. .
- the luminance compensation determiner 24 may determine an offset b ′, which is a luminance compensation parameter.
- the second layer decoder 26 may use the luminance compensation parameter determined by the luminance compensation determiner 24 to determine the luminance values Pred (x, y) and 6650 of each pixel of the first layer reference block.
- Luminance compensation may be performed by determining the sum of the offset b as the pixel values Pred '(x, y) of the luminance-compensated first layer reference block.
- 5C is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter, according to an exemplary embodiment.
- the luminance compensation determiner 24 of the interlayer video decoding apparatus 20 may determine whether the prediction mode of the second layer current block is a view synthesis prediction mode.
- the interlayer video decoding apparatus 20 refers to synthesizing an image of a view to be encoded by using an image of an adjacent view reconstructed in the view synthesis prediction mode. That is, after dividing the current block to be encoded into blocks of a predetermined unit, disparity information corresponding to each block may be derived from the depth map, and view compensation may be performed through the derived disparity information.
- the luminance compensation determiner 24 selects the second luminance compensation model, that is, the luminance compensation model using only the offset b ′, if the mode of the second layer current block to perform the luminance compensation is the view synthesis prediction mode. Can be.
- the luminance compensation determiner 24 may determine an offset (b ′) that is a luminance compensation parameter.
- the second layer decoder 26 uses the determined luminance compensation parameter to add luminance (b ') to each pixel value Pred (x, y) 6550 of the first layer reference block by using the luminance compensation parameter.
- Luminance compensation may be performed by determining each pixel value Pred '(x, y) of the compensated first layer reference block.
- the luminance compensation determiner 24 uses the first luminance compensation model, that is, the scale factor (a) and the offset (b), if the mode of the second layer current block to perform luminance compensation is not the view synthesis prediction mode.
- the luminance compensation model can be selected.
- the luminance compensation determiner 24 may determine the scale factor (a) and the offset (b) which are luminance compensation parameters.
- the second layer decoder 26 uses the luminance compensation parameter determined by the luminance compensation determiner 24 to determine the scale factor (a) for each pixel value Pred (x, y) of the first layer reference block.
- Luminance compensation may be performed by determining the pixel value Pred '(x, y) of the luminance-compensated first layer reference block as a result of multiplying the result of the multiplication by.
- 5D is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter, according to an exemplary embodiment.
- the luminance compensation determiner 24 of the interlayer video decoding apparatus 20 may determine that the color component of the second layer current block to which luminance compensation is to be performed is a chroma condition or the type of a picture including the current block is a depth map. It may be determined whether the condition or the current block corresponds to one of the conditions in the view synthesis prediction mode. If any one of the conditions of step 5310 is satisfied, in step 5370, the luminance compensation determiner 14 may select a luminance compensation model using only the second luminance compensation model, that is, the offset b ′. However, if none of the conditions of step 5310 is satisfied, the luminance compensation determiner 14 may select the first luminance compensation model in step 5320.
- Steps 5330, 5380, and 5340 of FIG. 5D are the same as steps 5230, 5280, and 5240 of FIG.
- the method of selecting the luminance compensation model and determining the luminance compensation parameter according to the embodiment of FIG. 5D may be performed according to the pseudo code of Table 2 below.
- Outputs of this process are:-a variable icWeight specifying a weight for illumination compensation,-a variable icOffset specifying a offset for illumination compensation,-a variable icShift specifying a bit shift for illumination compensation.
- icWeight is set equal to 1
- icOffset is set equal to 0
- icShift is set equal to 0.
- DepthFlag is equal to 1
- isOffset is equal to 1 or cIdx is not equal to 0
- sumRef sumRef
- sumCur are set equal to 0 and the following applies for i ranging from 0 to numSamples -1, inclusive.
- variable divCoeff is derived from Table H 11 depending on psDenomDiv.
- icShift specifying a bit shift for illumination compensation is set equal to 13.
- icWeight invPsIcWeight (H 198)-Otherwise, (invPsIcWeight is less than -2 ⁇ 6 or greater than or equal to 2 ⁇ 6), the following applies.
- decIcShift Max (0, Floor (Log2 (Abs (icWeight))-5)) (H 199)
- icWeight invPsIcWeight >> decIcShift (H 200)
- 5E is a flowchart of an operation of determining, by the luminance compensation determiner, a luminance compensation parameter according to an exemplary embodiment.
- illumination changes within a frame occur locally and do not require the same luminance compensation model for all regions in the image, ie all blocks in the image.
- Some blocks may need to perform adaptive luminance compensation on a block-by-block basis because coding efficiency may be lowered when luminance compensation is performed.
- a luminance compensation model using a first luminance compensation model that is, a scale factor (a) and an offset (b), or a second luminance compensation model, That is, it may be determined whether to select a luminance compensation model using only the offset b ', and it may be explicitly signaled to perform luminance compensation.
- the interlayer video decoding apparatus 20 may transfer a flag, such as a signaling bit in macroblock units, and select whether to compensate for luminance or a luminance compensation model, and transmit the flag to the luminance compensation determiner 24. . That is, in step 5410, the luminance compensation determiner 24 does not perform luminance compensation when the received flag is 0, and when 1, selects the first luminance compensation model (step 5420), and scale factor (a) and The offset b may be determined (step 5430), and in the case of 2, the second luminance compensation model may be selected (step 5470) and the offset b 'may be determined (step 5480). Since step 5440 is the same as step 5240 of FIG. 5C, a detailed description thereof will be omitted.
- a flag such as a signaling bit in macroblock units
- the interlayer video encoding apparatus 20 may signal according to a color component or a prediction mode of a block to perform luminance compensation.
- a luminance compensation model suitable for a luma component and a luminance compensation model suitable for a chroma component may be defined and signaled, respectively.
- a luma component can be signaled with a suitable luminance compensation model and the chroma component can always use the same luminance compensation model.
- the interlayer video encoding apparatus 10 may signal to use a second luminance compensation model using only an offset when the prediction mode of the current block is a view synthesis prediction mode.
- the mode may optionally be signaled to use a luminance compensation model.
- the luminance compensation determiner 24 performs a linear regression method, an average of difference based prediction, based on the neighboring pixel values of the second layer current block and the first layer reference block.
- FIGS. 5A, 5B, 5C, 5D, and 5E Although an example of selecting the luminance compensation model and determining the luminance compensation parameter in the interlayer video decoding apparatus 20 of FIGS. 5A, 5B, 5C, 5D, and 5E has been described, one of ordinary skill in the art to which the present invention pertains will be described. It will be appreciated that the method described in FIGS. 5A, 5B, 5C, 5D, and 5E may also be performed in the interlayer video encoding apparatus 10.
- FIG. 6 illustrates a method of determining a luminance compensation parameter according to an embodiment.
- the luminance compensation determiner 24 of the second layer decoder 26 includes the neighboring pixels NBref 6657 and NBcur 6170 of the first layer reference block 6500 and the second layer current block 6100. Determining the luminance compensation parameter using all or part of the) and performing luminance compensation using the first layer reference block 6500 and the second layer current block 6100 and the determined luminance compensation parameter.
- the layer reference block 6500 is out of the boundary of the first layer reconstructed image 6600, the reference block is not available as a reference block and cannot be used to calculate a luminance compensation parameter.
- the second layer current block may predict the parallax vector from the neighboring block, and the block indicated by the disparity vector of the predicted second layer current block 6100, that is, the first layer reference block 6500 may be formed.
- the first layer reference block 6500 and its surrounding pixels cannot be used when the one-layer reconstructed image 6600 is out of the boundary, the first layer reference block 6500 cannot be used and the luminance compensation parameter cannot be calculated. There is this.
- the luminance compensation determiner 14 of the interlayer video encoding apparatus 10 may determine that the luminance compensation determiner 14 is out of an area when the first layer reference block 6500 is out of the boundary of the first layer image 6600. Peripheral pixels of the out-of-area region may be replaced with pixels existing within a boundary of the first layer reconstructed image. According to an embodiment of the present disclosure, the luminance compensation determiner 14 may use the pixel value at the boundary of the first layer image 6600 to determine the first layer reference block 6500 from the boundary of the first layer image 6600. Padding can be done by substituting outside the bounds.
- the reference block By assigning the value of the boundary of the first layer image 6600 to the outside of the boundary of the first layer reference block 6500, the reference block can be used even if it is outside the boundary of the reference image, so that the luminance compensation parameter can be derived. The efficiency can be improved.
- the method of determining the luminance compensation parameter according to the embodiment of FIG. 6 may be performed according to the pseudo code of Table 3 below.
- puIvPredFlagLX 0
- puIcFlagLX 0
- puIvPredFlagLX 1
- yRLX yC + ((mvLX [ 1] + (cIdx?
- an interlayer video encoding apparatus 10 and an interlayer video decoding apparatus adaptively selecting a luminance compensation model for a block according to image characteristics and determining a luminance compensation parameter for the selected luminance compensation model. 20 has been proposed.
- the computational burden may be increased, so that only the blocks satisfying the predetermined condition Luminance compensation defined in Equation 3 and luminance compensation that adds only an offset defined in Equation 3 may be performed on blocks that do not satisfy a predetermined condition.
- blocks in which video data is divided are divided into coding units having a tree structure, and As described above, coding units, prediction units, and transformation units are sometimes used for inter-layer prediction or inter prediction.
- coding units, prediction units, and transformation units are sometimes used for inter-layer prediction or inter prediction.
- FIGS. 1-10 a video encoding method and apparatus therefor, a video decoding method, and an apparatus based on coding units and transformation units of a tree structure according to an embodiment will be described with reference to FIGS.
- the encoding / decoding process for the first layer images and the encoding / decoding process for the second layer images are performed separately. That is, when inter-layer prediction occurs in the multilayer video, the encoding / decoding result of the single layer video may be cross-referenced, but a separate encoding / decoding process occurs for each single layer video.
- the video encoding process and the video decoding process based on coding units having a tree structure described below with reference to FIGS. 7 to 19 are video encoding processes and video decoding processes for single layer video, and thus inter prediction and motion compensation are performed. This is detailed. However, as described above with reference to FIGS. 1A through 6, inter-layer prediction and compensation between base view images and second layer images are performed for encoding / decoding a video stream.
- the encoder 12 may perform video encoding for each single layer video.
- the video encoding apparatus 100 of FIG. 8 may be controlled to perform encoding of the single layer video allocated to each video encoding apparatus 100 by including the number of layers of the multilayer video.
- the interlayer video encoding apparatus 10 may perform inter-view prediction using encoding results of separate single views of each video encoding apparatus 100. Accordingly, the encoder 12 of the interlayer video encoding apparatus 10 may generate a base view video stream and a second layer video stream that contain encoding results for each layer.
- the decoder 26 of the interlayer video decoding apparatus 20 in order for the decoder 26 of the interlayer video decoding apparatus 20 according to an embodiment to decode a multilayer video based on a coding unit having a tree structure, the received first layer video stream and the second layer are decoded.
- the video decoding apparatus 200 of FIG. 9 includes the number of layers of the multilayer video, and performs decoding of the single layer video allocated to each video decoding apparatus 200.
- the interlayer video decoding apparatus 20 may perform interlayer prediction by using a decoding result of a separate single layer of each video decoding apparatus 200. Accordingly, the decoder 26 of the interlayer video decoding apparatus 20 may generate first layer images and second layer images reconstructed for each layer.
- FIG. 7 is a block diagram of a video encoding apparatus 100 based on coding units having a tree structure, according to an embodiment of the present invention.
- the video encoding apparatus 100 including video prediction based on coding units having a tree structure includes a coding unit determiner 120 and an output unit 130.
- the video encoding apparatus 100 that includes video prediction based on coding units having a tree structure is abbreviated as “video encoding apparatus 100”.
- the coding unit determiner 120 may partition the current picture based on a maximum coding unit that is a coding unit having a maximum size for the current picture of the image. If the current picture is larger than the maximum coding unit, image data of the current picture may be split into at least one maximum coding unit.
- the maximum coding unit may be a data unit having a size of 32x32, 64x64, 128x128, 256x256, or the like, and may be a square data unit having a square of two horizontal and vertical sizes.
- the coding unit according to an embodiment may be characterized by a maximum size and depth.
- the depth indicates the number of times the coding unit is spatially divided from the maximum coding unit, and as the depth increases, the coding unit for each depth may be split from the maximum coding unit to the minimum coding unit.
- the depth of the largest coding unit is the highest depth and the minimum coding unit may be defined as the lowest coding unit.
- the maximum coding unit decreases as the depth increases, the size of the coding unit for each depth decreases, and thus, the coding unit of the higher depth may include coding units of a plurality of lower depths.
- the image data of the current picture may be divided into maximum coding units according to the maximum size of the coding unit, and each maximum coding unit may include coding units divided by depths. Since the maximum coding unit is divided according to depths, image data of a spatial domain included in the maximum coding unit may be hierarchically classified according to depths.
- the maximum depth and the maximum size of the coding unit that limit the total number of times of hierarchically dividing the height and the width of the maximum coding unit may be preset.
- the coding unit determiner 120 encodes at least one divided region obtained by dividing the region of the largest coding unit for each depth, and determines a depth at which the final encoding result is output for each of the at least one divided region. That is, the coding unit determiner 120 encodes the image data in coding units according to depths for each maximum coding unit of the current picture, and selects the depth at which the smallest coding error occurs to determine the final depth. The determined final depth and the image data for each maximum coding unit are output to the outputter 130.
- Image data in the largest coding unit is encoded based on coding units according to depths according to at least one depth less than or equal to the maximum depth, and encoding results based on the coding units for each depth are compared. As a result of comparing the encoding error of the coding units according to depths, a depth having the smallest encoding error may be selected. At least one final depth may be determined for each maximum coding unit.
- the coding unit is divided into hierarchically and the number of coding units increases.
- a coding error of each data is measured, and whether or not division into a lower depth is determined. Therefore, even in the data included in one largest coding unit, since the encoding error for each depth is different according to the position, the final depth may be differently determined according to the position. Accordingly, one or more final depths may be set for one maximum coding unit, and data of the maximum coding unit may be partitioned according to coding units of one or more final depths.
- the coding unit determiner 120 may determine coding units having a tree structure included in the current maximum coding unit.
- the coding units according to the tree structure according to an embodiment include coding units having a depth determined as a final depth among all deeper coding units included in the current maximum coding unit.
- the coding unit of the final depth may be determined hierarchically according to the depth in the same region within the maximum coding unit, and may be independently determined for the other regions.
- the final depth for the current area can be determined independently of the final depth for the other area.
- the maximum depth according to an embodiment is an index related to the number of divisions from the maximum coding unit to the minimum coding unit.
- the first maximum depth according to an embodiment may represent the total number of divisions from the maximum coding unit to the minimum coding unit.
- the second maximum depth according to an embodiment may represent the total number of depth levels from the maximum coding unit to the minimum coding unit. For example, when the depth of the largest coding unit is 0, the depth of the coding unit obtained by dividing the largest coding unit once may be set to 1, and the depth of the coding unit divided twice may be set to 2. In this case, if the coding unit divided four times from the maximum coding unit is the minimum coding unit, since depth levels of 0, 1, 2, 3, and 4 exist, the first maximum depth is set to 4 and the second maximum depth is set to 5. Can be.
- Predictive encoding and transformation of the largest coding unit may be performed. Similarly, prediction encoding and transformation are performed based on depth-wise coding units for each maximum coding unit and for each depth less than or equal to the maximum depth.
- encoding including prediction encoding and transformation should be performed on all the coding units for each depth generated as the depth deepens.
- the prediction encoding and the transformation will be described based on the coding unit of the current depth among at least one maximum coding unit.
- the video encoding apparatus 100 may variously select a size or shape of a data unit for encoding image data.
- the encoding of the image data is performed through prediction encoding, transforming, entropy encoding, and the like.
- the same data unit may be used in every step, or the data unit may be changed in steps.
- the video encoding apparatus 100 may select not only a coding unit for encoding the image data, but also a data unit different from the coding unit in order to perform predictive encoding of the image data in the coding unit.
- prediction encoding may be performed based on coding units of a final depth, that is, stranger undivided coding units, according to an embodiment.
- a more strange undivided coding unit that is the basis of prediction coding is referred to as a 'prediction unit'.
- the partition in which the prediction unit is divided may include a data unit in which at least one of the prediction unit and the height and the width of the prediction unit are divided.
- the partition may be a data unit in which the prediction unit of the coding unit is split, and the prediction unit may be a partition having the same size as the coding unit.
- the partition mode may be formed in a geometric form, as well as partitions divided in an asymmetric ratio such as 1: n or n: 1, as well as symmetric partitions in which a height or width of a prediction unit is divided in a symmetrical ratio. It may optionally include partitioned partitions, arbitrary types of partitions, and the like.
- the prediction mode of the prediction unit may be at least one of an intra mode, an inter mode, and a skip mode.
- the intra mode and the inter mode may be performed on partitions having sizes of 2N ⁇ 2N, 2N ⁇ N, N ⁇ 2N, and N ⁇ N.
- the skip mode may be performed only for partitions having a size of 2N ⁇ 2N.
- the encoding may be performed independently for each prediction unit within the coding unit to select a prediction mode having the smallest encoding error.
- the video encoding apparatus 100 may perform conversion of image data of a coding unit based on not only a coding unit for encoding image data, but also a data unit different from the coding unit.
- the transformation may be performed based on a transformation unit having a size smaller than or equal to the coding unit.
- the transformation unit may include a data unit for intra mode and a transformation unit for inter mode.
- the transformation unit in the coding unit is also recursively divided into smaller transformation units, so that the residual data of the coding unit is determined according to the tree structure according to the transformation depth. Can be partitioned according to the conversion unit.
- a transform depth indicating a number of divisions between the height and the width of the coding unit divided to the transform unit may be set. For example, if the size of the transform unit of the current coding unit of size 2Nx2N is 2Nx2N, the transform depth is 0, the transform depth 1 if the size of the transform unit is NxN, and the transform depth 2 if the size of the transform unit is N / 2xN / 2. Can be. That is, the transformation unit having a tree structure may also be set for the transformation unit according to the transformation depth.
- the split information for each depth requires not only depth but also prediction related information and transformation related information. Accordingly, the coding unit determiner 120 may determine not only the depth that generated the minimum encoding error, but also a partition mode in which the prediction unit is divided into partitions, a prediction mode for each prediction unit, and a size of a transformation unit for transformation.
- a method of determining a coding unit, a prediction unit / partition, and a transformation unit according to a tree structure of a maximum coding unit according to an embodiment will be described in detail with reference to FIGS. 9 to 19.
- the coding unit determiner 120 may measure a coding error of coding units according to depths using a Lagrangian Multiplier-based rate-distortion optimization technique.
- the output unit 130 outputs the image data and the split information according to depths of the maximum coding unit, which are encoded based on at least one depth determined by the coding unit determiner 120, in a bitstream form.
- the encoded image data may be a result of encoding residual data of the image.
- the split information for each depth may include depth information, partition mode information of a prediction unit, prediction mode information, split information of a transformation unit, and the like.
- the final depth information may be defined using depth-specific segmentation information indicating whether to encode in a coding unit of a lower depth rather than encoding the current depth. If the current depth of the current coding unit is a depth, since the current coding unit is encoded in a coding unit of the current depth, split information of the current depth may be defined so that it is no longer divided into lower depths. On the contrary, if the current depth of the current coding unit is not the depth, encoding should be attempted using the coding unit of the lower depth, and thus split information of the current depth may be defined to be divided into coding units of the lower depth.
- encoding is performed on the coding unit divided into the coding units of the lower depth. Since at least one coding unit of a lower depth exists in the coding unit of the current depth, encoding may be repeatedly performed for each coding unit of each lower depth, and recursive coding may be performed for each coding unit of the same depth.
- coding units having a tree structure are determined in one largest coding unit and at least one split information should be determined for each coding unit of a depth, at least one split information may be determined for one maximum coding unit.
- the depth since the data of the largest coding unit is partitioned hierarchically according to the depth, the depth may be different for each location, and thus depth and split information may be set for the data.
- the output unit 130 may allocate encoding information about a corresponding depth and an encoding mode to at least one of a coding unit, a prediction unit, and a minimum unit included in the maximum coding unit.
- the minimum unit according to an embodiment is a square data unit having a size obtained by dividing a minimum coding unit, which is the lowest depth, into four divisions.
- the minimum unit according to an embodiment may be a square data unit having a maximum size that may be included in all coding units, prediction units, partition units, and transformation units included in the maximum coding unit.
- the encoding information output through the output unit 130 may be classified into encoding information according to depth coding units and encoding information according to prediction units.
- the encoding information for each coding unit according to depth may include prediction mode information and partition size information.
- the encoding information transmitted for each prediction unit includes information about an estimation direction of the inter mode, information about a reference image index of the inter mode, information about a motion vector, information about a chroma component of an intra mode, and information about an inter mode of an intra mode. And the like.
- Information about the maximum size and information about the maximum depth of the coding unit defined for each picture, slice, or GOP may be inserted into a header, a sequence parameter set, or a picture parameter set of the bitstream.
- the information on the maximum size of the transform unit and the minimum size of the transform unit allowed for the current video may also be output through a header, a sequence parameter set, a picture parameter set, or the like of the bitstream.
- the output unit 130 may encode and output reference information, prediction information, slice type information, and the like related to prediction.
- a coding unit according to depths is a coding unit having a size in which a height and a width of a coding unit of one layer higher depth are divided by half. That is, if the size of the coding unit of the current depth is 2Nx2N, the size of the coding unit of the lower depth is NxN.
- the current coding unit having a size of 2N ⁇ 2N may include up to four lower depth coding units having a size of N ⁇ N.
- the video encoding apparatus 100 determines a coding unit having an optimal shape and size for each maximum coding unit based on the size and the maximum depth of the maximum coding unit determined in consideration of the characteristics of the current picture. Coding units may be configured. In addition, since each of the maximum coding units may be encoded in various prediction modes and transformation methods, an optimal coding mode may be determined in consideration of image characteristics of coding units having various image sizes.
- the video encoding apparatus may adjust the coding unit in consideration of the image characteristics while increasing the maximum size of the coding unit in consideration of the size of the image, thereby increasing image compression efficiency.
- the interlayer video encoding apparatus 10 described above with reference to FIG. 1A may include as many video encoding apparatuses 100 as the number of layers for encoding single layer images for each layer of a multilayer video.
- the first layer encoder 12 may include one video encoding apparatus 100
- the second layer encoder 14 may include as many video encoding apparatuses 100 as the number of second layers. Can be.
- the coding unit determiner 120 determines a prediction unit for inter-image prediction for each coding unit having a tree structure for each maximum coding unit, and for each prediction unit. Inter-prediction may be performed.
- the coding unit determiner 120 determines a coding unit and a prediction unit having a tree structure for each maximum coding unit, and performs inter prediction for each prediction unit. Can be.
- the video encoding apparatus 100 may encode the luminance difference to compensate for the luminance difference between the first layer image and the second layer image.
- FIG. 8 is a block diagram of a video decoding apparatus 200 based on coding units having a tree structure, according to various embodiments.
- a video decoding apparatus 200 including video prediction based on coding units having a tree structure includes a receiver 210, image data and encoding information extractor 220, and image data decoder 230. do.
- the video decoding apparatus 200 that includes video prediction based on coding units having a tree structure is abbreviated as “video decoding apparatus 200”.
- the receiver 210 receives and parses a bitstream of an encoded video.
- the image data and encoding information extractor 220 extracts image data encoded for each coding unit from the parsed bitstream according to coding units having a tree structure for each maximum coding unit, and outputs the encoded image data to the image data decoder 230.
- the image data and encoding information extractor 220 may extract information about a maximum size of a coding unit of the current picture from a header, a sequence parameter set, or a picture parameter set for the current picture.
- the image data and encoding information extractor 220 extracts the final depth and the split information of the coding units having a tree structure for each maximum coding unit from the parsed bitstream.
- the extracted final depth and split information are output to the image data decoder 230. That is, the image data of the bit string may be divided into maximum coding units so that the image data decoder 230 may decode the image data for each maximum coding unit.
- the depth and split information for each largest coding unit may be set for one or more depth information, and the split information for each depth may include partition mode information, prediction mode information, split information of a transform unit, and the like, of a corresponding coding unit. .
- depth-specific segmentation information may be extracted.
- the depth and split information for each largest coding unit extracted by the image data and encoding information extractor 220 are repeatedly used for each coding unit for each deeper coding unit, as in the video encoding apparatus 100 according to an exemplary embodiment. Depth and split information determined to perform encoding to generate a minimum encoding error. Therefore, the video decoding apparatus 200 may reconstruct an image by decoding data according to an encoding method that generates a minimum encoding error.
- the image data and the encoding information extractor 220 may use the predetermined data unit. Depth and segmentation information can be extracted for each. If the depth and the split information of the corresponding maximum coding unit are recorded for each predetermined data unit, the predetermined data units having the same depth and the split information may be inferred as data units included in the same maximum coding unit.
- the image data decoder 230 reconstructs the current picture by decoding image data of each maximum coding unit based on the depth and the split information for each maximum coding unit. That is, the image data decoder 230 may decode the encoded image data based on the read partition mode, the prediction mode, and the transformation unit for each coding unit among the coding units having the tree structure included in the maximum coding unit. Can be.
- the decoding process may include a prediction process including intra prediction and motion compensation, and an inverse transform process.
- the image data decoder 230 may perform intra prediction or motion compensation according to each partition and prediction mode for each coding unit, based on the partition mode information and the prediction mode information of the prediction unit of the coding unit according to depths.
- the image data decoder 230 may read transform unit information having a tree structure for each coding unit, and perform inverse transform based on the transformation unit for each coding unit, for inverse transformation for each largest coding unit. Through inverse transformation, the pixel value of the spatial region of the coding unit may be restored.
- the image data decoder 230 may determine the depth of the current maximum coding unit by using the split information for each depth. If the split information indicates that the split information is no longer divided at the current depth, the current depth is the depth. Therefore, the image data decoder 230 may decode the coding unit of the current depth using the partition mode, the prediction mode, and the transformation unit size information of the prediction unit, for the image data of the current maximum coding unit.
- the image data decoder 230 It may be regarded as one data unit to be decoded in the same encoding mode.
- the decoding of the current coding unit may be performed by obtaining information about an encoding mode for each coding unit determined in this way.
- the interlayer video decoding apparatus 20 described above with reference to FIG. 2A decodes the received first layer image stream and the second layer image stream to reconstruct the first layer images and the second layer images.
- the device 200 may include the number of viewpoints.
- the image data decoder 230 of the video decoding apparatus 200 may maximize the samples of the first layer images extracted from the first layer image stream by the extractor 220. It may be divided into coding units having a tree structure of the coding units. The image data decoder 230 may reconstruct the first layer images by performing motion compensation for each coding unit according to a tree structure of samples of the first layer images, for each prediction unit for inter-image prediction.
- the image data decoder 230 of the video decoding apparatus 200 may maximize the samples of the second layer images extracted from the second layer image stream by the extractor 220. It may be divided into coding units having a tree structure of the coding units. The image data decoder 230 may reconstruct the second layer images by performing motion compensation for each prediction unit for inter-image prediction for each coding unit of the samples of the second layer images.
- the extractor 220 may obtain information related to the luminance error from the bitstream to compensate for the luminance difference between the first layer image and the second layer image. However, the amount of computation can be reduced by adaptively selecting the luminance compensation model according to the image characteristic.
- the video decoding apparatus 200 may obtain information about a coding unit that generates a minimum coding error by recursively encoding each maximum coding unit in the encoding process, and use the same to decode the current picture. That is, decoding of encoded image data of coding units having a tree structure determined as an optimal coding unit for each maximum coding unit can be performed.
- the image data is efficiently decoded according to the size and encoding mode of a coding unit adaptively determined according to the characteristics of the image using the optimal split information transmitted from the encoding end. Can be restored
- FIG 9 illustrates a concept of coding units, according to various embodiments.
- a size of a coding unit may be expressed by a width x height, and may include 32x32, 16x16, and 8x8 from a coding unit having a size of 64x64.
- Coding units of size 64x64 may be partitioned into partitions of size 64x64, 64x32, 32x64, and 32x32, coding units of size 32x32 are partitions of size 32x32, 32x16, 16x32, and 16x16, and coding units of size 16x16 are 16x16.
- Coding units of size 8x8 may be divided into partitions of size 8x8, 8x4, 4x8, and 4x4, into partitions of 16x8, 8x16, and 8x8.
- the resolution is set to 1920x1080, the maximum size of the coding unit is 64, and the maximum depth is 2.
- the resolution is set to 1920x1080, the maximum size of the coding unit is 64, and the maximum depth is 3.
- the resolution is set to 352x288, the maximum size of the coding unit is 16, and the maximum depth is 1.
- the maximum depth illustrated in FIG. 10 represents the total number of divisions from the maximum coding unit to the minimum coding unit.
- the maximum size of the coding size is relatively large not only to improve the coding efficiency but also to accurately shape the image characteristics. Accordingly, the video data 310 or 320 having a higher resolution than the video data 330 may be selected to have a maximum size of 64.
- the coding unit 315 of the video data 310 is divided twice from a maximum coding unit having a long axis size of 64, and the depth is deepened by two layers, so that the long axis size is 32, 16. Up to coding units may be included.
- the coding unit 335 of the video data 330 is divided once from coding units having a long axis size of 16, and the depth is deepened by one layer to increase the long axis size to 8. Up to coding units may be included.
- the coding unit 325 of the video data 320 is divided three times from the largest coding unit having a long axis size of 64, and the depth is three layers deep, so that the long axis size is 32, 16. , Up to 8 coding units may be included. As the depth increases, the expressive power of the detailed information may be improved.
- FIG. 10 is a block diagram of an image encoder 400 based on coding units, according to various embodiments.
- the image encoder 400 performs operations that are performed to encode image data by the picture encoder 120 of the video encoding apparatus 100. That is, the intra prediction unit 420 performs intra prediction on each coding unit of the intra mode of the current image 405, and the inter prediction unit 415 performs the current image on the prediction unit of the coding unit of the inter mode. Inter-prediction is performed using the reference image acquired at 405 and the reconstructed picture buffer 410.
- the current image 405 may be divided into maximum coding units and then sequentially encoded. In this case, encoding may be performed on the coding unit in which the largest coding unit is to be divided into a tree structure.
- Residual data is generated by subtracting the prediction data for the coding unit of each mode output from the intra prediction unit 420 or the inter prediction unit 415 from the data for the encoding unit of the current image 405, and
- the dew data is output as transform coefficients quantized for each transform unit through the transform unit 425 and the quantization unit 430.
- the quantized transform coefficients are reconstructed into residue data in the spatial domain through the inverse quantizer 445 and the inverse transformer 450.
- Residual data of the reconstructed spatial domain is added to the prediction data of the coding unit of each mode output from the intra predictor 420 or the inter predictor 415, thereby adding the residual data of the spatial domain to the coding unit of the current image 405. The data is restored.
- the reconstructed spatial region data is generated as a reconstructed image through the deblocking unit 455 and the SAO performing unit 460.
- the generated reconstructed image is stored in the reconstructed picture buffer 410.
- the reconstructed images stored in the reconstructed picture buffer 410 may be used as reference images for inter prediction of another image.
- the transform coefficients quantized by the transformer 425 and the quantizer 430 may be output as the bitstream 440 through the entropy encoder 435.
- an inter predictor 415, an intra predictor 420, and a transformer each have a tree structure for each maximum coding unit. An operation based on each coding unit among the coding units may be performed.
- the intra prediction unit 420 and the inter prediction unit 415 determine the partition mode and the prediction mode of each coding unit among the coding units having a tree structure in consideration of the maximum size and the maximum depth of the current maximum coding unit.
- the transform unit 425 may determine whether to split the transform unit according to the quad tree in each coding unit among the coding units having the tree structure.
- FIG. 11 is a block diagram of an image decoder 500 based on coding units, according to various embodiments.
- the entropy decoding unit 515 parses the encoded image data to be decoded from the bitstream 505 and encoding information necessary for decoding.
- the encoded image data is a quantized transform coefficient
- the inverse quantizer 520 and the inverse transform unit 525 reconstruct residue data from the quantized transform coefficients.
- the intra prediction unit 540 performs intra prediction for each prediction unit with respect to the coding unit of the intra mode.
- the inter prediction unit 535 performs inter prediction using the reference image obtained from the reconstructed picture buffer 530 for each coding unit of the coding mode of the inter mode among the current pictures.
- the data of the spatial domain of the coding unit of the current image 405 is reconstructed and restored.
- the data of the space area may be output as a reconstructed image 560 via the deblocking unit 545 and the SAO performing unit 550.
- the reconstructed images stored in the reconstructed picture buffer 530 may be output as reference images.
- step-by-step operations after the entropy decoder 515 of the image decoder 500 may be performed.
- the entropy decoder 515, the inverse quantizer 520, and the inverse transformer ( 525, the intra prediction unit 540, the inter prediction unit 535, the deblocking unit 545, and the SAO performer 550 based on each coding unit among coding units having a tree structure for each maximum coding unit. You can do it.
- the intra predictor 540 and the inter predictor 535 determine a partition mode and a prediction mode for each coding unit among coding units having a tree structure, and the inverse transformer 525 has a quad tree structure for each coding unit. It is possible to determine whether to divide the conversion unit according to.
- the encoding operation of FIG. 10 and the decoding operation of FIG. 11 describe the video stream encoding operation and the decoding operation in a single layer, respectively. Therefore, if the encoder 12 of FIG. 1A encodes a video stream of two or more layers, the encoder 12 may include an image encoder 400 for each layer. Similarly, if the decoder 26 of FIG. 2A decodes a video stream of two or more layers, it may include an image decoder 500 for each layer.
- FIG. 12 is a diagram illustrating deeper coding units according to depths, and partitions, according to various embodiments.
- the video encoding apparatus 100 according to an embodiment and the video decoding apparatus 200 according to an embodiment use hierarchical coding units to consider image characteristics.
- the maximum height, width, and maximum depth of the coding unit may be adaptively determined according to the characteristics of the image, and may be variously set according to a user's request. According to the maximum size of the preset coding unit, the size of the coding unit for each depth may be determined.
- the hierarchical structure 600 of a coding unit illustrates a case in which a maximum height and a width of a coding unit are 64 and a maximum depth is three.
- the maximum depth indicates the total number of divisions from the maximum coding unit to the minimum coding unit. Since the depth deepens along the vertical axis of the hierarchical structure 600 of the coding unit according to an embodiment, the height and the width of the coding unit for each depth are divided.
- a prediction unit and a partition on which the prediction encoding of each depth-based coding unit is shown along the horizontal axis of the hierarchical structure 600 of the coding unit are illustrated.
- the coding unit 610 has a depth of 0 as the largest coding unit of the hierarchical structure 600 of the coding unit, and the size, ie, the height and width, of the coding unit is 64x64.
- a depth deeper along the vertical axis includes a coding unit 620 of depth 1 having a size of 32x32, a coding unit 630 of depth 2 having a size of 16x16, and a coding unit 640 of depth 3 having a size of 8x8.
- a coding unit 640 of depth 3 having a size of 8 ⁇ 8 is a minimum coding unit.
- Prediction units and partitions of the coding unit are arranged along the horizontal axis for each depth. That is, if the coding unit 610 of size 64x64 having a depth of zero is a prediction unit, the prediction unit may include a partition 610 of size 64x64, partitions 612 of size 64x32, and size included in the coding unit 610 of size 64x64. 32x64 partitions 614, 32x32 partitions 616.
- the prediction unit of the coding unit 620 having a size of 32x32 having a depth of 1 includes a partition 620 of size 32x32, partitions 622 of size 32x16 and a partition of size 16x32 included in the coding unit 620 of size 32x32. 624, partitions 626 of size 16x16.
- the prediction unit of the coding unit 630 of size 16x16 having a depth of 2 includes a partition 630 of size 16x16, partitions 632 of size 16x8, and a partition of size 8x16 included in the coding unit 630 of size 16x16. 634, partitions 636 of size 8x8.
- the prediction unit of the coding unit 640 of size 8x8 having a depth of 3 includes a partition 640 of size 8x8, partitions 642 of size 8x4 and a partition of size 4x8 included in the coding unit 640 of size 8x8. 644, partitions 646 of size 4x4.
- the coding unit determiner 120 of the video encoding apparatus 100 may determine the depth of the maximum coding unit 610 for each coding unit of each depth included in the maximum coding unit 610. Encoding must be performed.
- the number of deeper coding units according to depths for including data having the same range and size increases as the depth increases. For example, four coding units of depth 2 are required for data included in one coding unit of depth 1. Therefore, in order to compare the encoding results of the same data for each depth, each of the coding units having one depth 1 and four coding units having four depths 2 should be encoded.
- encoding may be performed for each prediction unit of a coding unit according to depths along a horizontal axis of the hierarchical structure 600 of the coding unit, and a representative coding error, which is the smallest coding error at a corresponding depth, may be selected. .
- a depth deeper along the vertical axis of the hierarchical structure 600 of the coding unit the encoding may be performed for each depth, and the minimum coding error may be searched by comparing the representative coding error for each depth.
- the depth and partition in which the minimum coding error occurs in the maximum coding unit 610 may be selected as the depth and partition mode of the maximum coding unit 610.
- FIG. 13 illustrates a relationship between a coding unit and transformation units, according to various embodiments.
- the video encoding apparatus 100 encodes or decodes an image in coding units having a size smaller than or equal to the maximum coding unit for each maximum coding unit.
- the size of a transformation unit for transformation in the encoding process may be selected based on a data unit that is not larger than each coding unit.
- the 32x32 size conversion unit 720 is The conversion can be performed.
- the data of the 64x64 coding unit 710 is transformed into 32x32, 16x16, 8x8, and 4x4 transform units of 64x64 size or less, and then encoded, and the transform unit having the least error with the original is selected. Can be.
- FIG. 14 is a diagram of deeper encoding information according to depths, according to various embodiments.
- the output unit 130 of the video encoding apparatus 100 is split information, and information about a partition mode 800, information 810 about a prediction mode, and transform unit size for each coding unit of each depth.
- Information 820 may be encoded and transmitted.
- the information about the partition mode 800 is a data unit for predictive encoding of the current coding unit and indicates information about a partition type in which the prediction unit of the current coding unit is divided.
- the current coding unit CU_0 of size 2Nx2N may be any one of a partition 802 of size 2Nx2N, a partition 804 of size 2NxN, a partition 806 of size Nx2N, and a partition 808 of size NxN. It can be divided and used.
- the information 800 about the partition mode of the current coding unit represents one of a partition 802 of size 2Nx2N, a partition 804 of size 2NxN, a partition 806 of size Nx2N, and a partition 808 of size NxN. It is set to.
- Information 810 relating to the prediction mode indicates the prediction mode of each partition. For example, through the information 810 about the prediction mode, whether the partition indicated by the information 800 about the partition mode is performed in one of the intra mode 812, the inter mode 814, and the skip mode 816 is performed. Whether or not can be set.
- the information about the transform unit size 820 indicates whether to transform the current coding unit based on the transform unit.
- the transform unit may be one of a first intra transform unit size 822, a second intra transform unit size 824, a first inter transform unit size 826, and a second inter transform unit size 828. have.
- the image data and encoding information extractor 210 of the video decoding apparatus 200 may include information about a partition mode 800, information 810 about a prediction mode, and transformation for each depth-based coding unit. Information 820 about the unit size may be extracted and used for decoding.
- 15 is a diagram of deeper coding units according to depths, according to various embodiments.
- Segmentation information may be used to indicate a change in depth.
- the split information indicates whether a coding unit of a current depth is split into coding units of a lower depth.
- the prediction unit 910 for predictive encoding of the coding unit 900 having depth 0 and 2N_0x2N_0 size includes a partition mode 912 having a size of 2N_0x2N_0, a partition mode 914 having a size of 2N_0xN_0, a partition mode 916 having a size of N_0x2N_0, and N_0xN_0 May include a partition mode 918 of size. Although only partitions 912, 914, 916, and 918 in which the prediction unit is divided by a symmetrical ratio are illustrated, as described above, the partition mode is not limited thereto, and asymmetric partitions, arbitrary partitions, geometric partitions, and the like. It may include.
- prediction coding For each partition mode, prediction coding must be performed repeatedly for one 2N_0x2N_0 partition, two 2N_0xN_0 partitions, two N_0x2N_0 partitions, and four N_0xN_0 partitions.
- prediction encoding For partitions having a size 2N_0x2N_0, a size N_0x2N_0, a size 2N_0xN_0, and a size N_0xN_0, prediction encoding may be performed in an intra mode and an inter mode.
- the skip mode may be performed only for prediction encoding on partitions having a size of 2N_0x2N_0.
- the depth 0 is changed to 1 and split (920), and the encoding is repeatedly performed on the depth 2 and the coding units 930 of the partition mode of size N_0xN_0.
- the depth 1 is changed to the depth 2 and split (950), and repeatedly for the depth 2 and the coding units 960 of the size N_2xN_2.
- the encoding may be performed to search for a minimum encoding error.
- depth-based coding units may be set until depth d-1, and split information may be set up to depth d-2. That is, when encoding is performed from the depth d-2 to the depth d-1 to the depth d-1, the prediction encoding of the coding unit 980 of the depth d-1 and the size 2N_ (d-1) x2N_ (d-1)
- the prediction unit for 990 is a partition mode 992 of size 2N_ (d-1) x2N_ (d-1), a partition mode 994 of size 2N_ (d-1) xN_ (d-1), and size
- a partition mode 996 of N_ (d-1) x2N_ (d-1) and a partition mode 998 of size N_ (d-1) xN_ (d-1) may be included.
- partition mode one partition 2N_ (d-1) x2N_ (d-1), two partitions 2N_ (d-1) xN_ (d-1), two sizes N_ (d-1) x2N_
- a partition mode in which a minimum encoding error occurs may be searched.
- the coding unit CU_ (d-1) of the depth d-1 is no longer
- the depth of the current maximum coding unit 900 may be determined as the depth d-1, and the partition mode may be determined as N_ (d-1) xN_ (d-1) without going through a division process into lower depths.
- split information is not set for the coding unit 952 having the depth d-1.
- the data unit 999 may be referred to as a 'minimum unit' for the current maximum coding unit.
- the minimum unit may be a square data unit having a size obtained by dividing the minimum coding unit, which is the lowest depth, into four segments.
- the video encoding apparatus 100 compares depth-to-depth encoding errors of the coding units 900, selects a depth at which the smallest encoding error occurs, and determines a depth.
- the partition mode and the prediction mode may be set to the encoding mode of the depth.
- depths with the smallest error can be determined by comparing the minimum coding errors for all depths of depths 0, 1, ..., d-1, and d.
- the depth, the partition mode of the prediction unit, and the prediction mode may be encoded and transmitted as split information.
- the coding unit since the coding unit must be split from the depth 0 to the depth, only the split information of the depth is set to '0', and the split information for each depth except the depth should be set to '1'.
- the image data and encoding information extractor 220 of the video decoding apparatus 200 may extract information about a depth and a prediction unit of the coding unit 900 and use it to decode the coding unit 912. have.
- the video decoding apparatus 200 may grasp a depth having split information of '0' as a depth using split information for each depth, and may use the split information for the corresponding depth for decoding.
- 16, 17, and 18 illustrate a relationship between coding units, prediction units, and transformation units, according to various embodiments.
- the coding units 1010 are deeper coding units determined by the video encoding apparatus 100 according to an embodiment with respect to the largest coding unit.
- the prediction unit 1060 is partitions of prediction units of each deeper coding unit among the coding units 1010, and the transform unit 1070 is transform units of each deeper coding unit.
- the depth-based coding units 1010 have a depth of 0
- the coding units 1012 and 1054 have a depth of 1
- the coding units 1014, 1016, 1018, 1028, 1050, and 1052 have depths.
- coding units 1020, 1022, 1024, 1026, 1030, 1032, and 1048 have a depth of three
- coding units 1040, 1042, 1044, and 1046 have a depth of four.
- partitions 1014, 1016, 1022, 1032, 1048, 1050, 1052, and 1054 of the prediction units 1060 are obtained by splitting coding units. That is, partitions 1014, 1022, 1050, and 1054 are 2NxN partition modes, partitions 1016, 1048, and 1052 are Nx2N partition modes, and partitions 1032 are NxN partition modes. Prediction units and partitions of the coding units 1010 according to depths are smaller than or equal to each coding unit.
- the image data of the part 1052 of the transformation units 1070 is transformed or inversely transformed into a data unit having a smaller size than the coding unit.
- the transformation units 1014, 1016, 1022, 1032, 1048, 1050, 1052, and 1054 are data units having different sizes or shapes when compared to corresponding prediction units and partitions among the prediction units 1060. That is, the video encoding apparatus 100 according to an embodiment and the video decoding apparatus 200 according to an embodiment may be intra prediction / motion estimation / motion compensation operations and transform / inverse transform operations for the same coding unit. Each can be performed on a separate data unit.
- coding is performed recursively for each coding unit having a hierarchical structure for each largest coding unit to determine an optimal coding unit.
- coding units having a recursive tree structure may be configured.
- the encoding information may include split information about the coding unit, partition mode information, prediction mode information, and transformation unit size information. Table 4 below shows an example that can be set in the video encoding apparatus 100 and the video decoding apparatus 200 according to an embodiment.
- the output unit 130 of the video encoding apparatus 100 outputs encoding information about coding units having a tree structure
- the encoding information extraction unit of the video decoding apparatus 200 according to an embodiment 220 may extract encoding information about coding units having a tree structure from the received bitstream.
- the split information indicates whether the current coding unit is split into coding units of a lower depth. If the split information of the current depth d is 0, partition mode information, prediction mode, and transform unit size information may be defined for the depth since the current coding unit is a depth in which the current coding unit is no longer divided into lower coding units. have. If it is to be further split by the split information, encoding should be performed independently for each coding unit of the divided four lower depths.
- the prediction mode may be represented by one of an intra mode, an inter mode, and a skip mode.
- Intra mode and inter mode can be defined in all partition modes, and skip mode can only be defined in partition mode 2Nx2N.
- the partition mode information indicates symmetric partition modes 2Nx2N, 2NxN, Nx2N, and NxN, in which the height or width of the prediction unit is divided by symmetrical ratios, and asymmetric partition modes 2NxnU, 2NxnD, nLx2N, nRx2N, divided by asymmetrical ratios.
- the asymmetric partition modes 2NxnU and 2NxnD are divided into heights of 1: 3 and 3: 1, respectively, and the asymmetric partition modes nLx2N and nRx2N are divided into 1: 3 and 3: 1 widths, respectively.
- the conversion unit size may be set to two kinds of sizes in the intra mode and two kinds of sizes in the inter mode. That is, if the transformation unit split information is 0, the size of the transformation unit is set to the size 2Nx2N of the current coding unit. If the transform unit split information is 1, a transform unit having a size obtained by dividing the current coding unit may be set. In addition, if the partition mode for the current coding unit having a size of 2Nx2N is a symmetric partition mode, the size of the transform unit may be set to NxN, and N / 2xN / 2 if it is an asymmetric partition mode.
- Encoding information of coding units having a tree structure may be allocated to at least one of a coding unit, a prediction unit, and a minimum unit unit of a depth.
- the coding unit of the depth may include at least one prediction unit and at least one minimum unit having the same encoding information.
- the encoding information held by each adjacent data unit is checked, it may be determined whether the data is included in the coding unit having the same depth.
- the coding unit of the corresponding depth may be identified using the encoding information held by the data unit, the distribution of depths within the maximum coding unit may be inferred.
- the encoding information of the data unit in the depth-specific coding unit adjacent to the current coding unit may be directly referred to and used.
- the prediction coding when the prediction coding is performed by referring to the neighboring coding unit, the data adjacent to the current coding unit in the coding unit according to depths is encoded by using the encoding information of the adjacent coding units according to depths.
- the neighboring coding unit may be referred to by searching.
- FIG. 19 illustrates a relationship between a coding unit, a prediction unit, and a transformation unit, according to encoding mode information of Table 1.
- the maximum coding unit 1300 includes coding units 1302, 1304, 1306, 1312, 1314, 1316, and 1318 of depths. Since one coding unit 1318 is a coding unit of depth, split information may be set to zero.
- the partition mode information of the coding unit 1318 having a size of 2Nx2N includes partition modes 2Nx2N 1322, 2NxN 1324, Nx2N 1326, NxN 1328, 2NxnU 1332, 2NxnD 1334, and nLx2N (1336). And nRx2N 1338.
- the transform unit split information (TU size flag) is a type of transform index, and a size of a transform unit corresponding to the transform index may be changed according to a prediction unit type or a partition mode of the coding unit.
- the partition mode information is set to one of symmetric partition modes 2Nx2N 1322, 2NxN 1324, Nx2N 1326, and NxN 1328
- the conversion unit partition information is 0, a conversion unit of size 2Nx2N ( 1342 is set, and if the transform unit split information is 1, a transform unit 1344 of size NxN may be set.
- partition mode information is set to one of asymmetric partition modes 2NxnU (1332), 2NxnD (1334), nLx2N (1336), and nRx2N (1338), if the conversion unit partition information (TU size flag) is 0, a conversion unit of size 2Nx2N ( 1352 is set, and if the transform unit split information is 1, a transform unit 1354 of size N / 2 ⁇ N / 2 may be set.
- the conversion unit splitting information (TU size flag) described above with reference to FIG. 19 is a flag having a value of 0 or 1, but the conversion unit splitting information according to an embodiment is not limited to a 1-bit flag and is set according to a setting. , 1, 2, 3., etc., and may be divided hierarchically.
- the transformation unit partition information may be used as an embodiment of the transformation index.
- the size of the transformation unit actually used may be expressed.
- the video encoding apparatus 100 may encode maximum transform unit size information, minimum transform unit size information, and maximum transform unit split information.
- the encoded maximum transform unit size information, minimum transform unit size information, and maximum transform unit split information may be inserted into the SPS.
- the video decoding apparatus 200 may use the maximum transform unit size information, the minimum transform unit size information, and the maximum transform unit split information to use for video decoding.
- the maximum transform unit split information is defined as 'MaxTransformSizeIndex'
- the minimum transform unit size is 'MinTransformSize'
- the transform unit split information is 0,
- the minimum transform unit possible in the current coding unit is defined as 'RootTuSize'.
- the size 'CurrMinTuSize' can be defined as in relation (1) below.
- 'RootTuSize' which is a transform unit size when the transform unit split information is 0, may indicate a maximum transform unit size that can be adopted in the system. That is, according to relation (1), 'RootTuSize / (2 ⁇ MaxTransformSizeIndex)' is a transformation obtained by dividing 'RootTuSize', which is the size of the transformation unit when the transformation unit division information is 0, by the number of times corresponding to the maximum transformation unit division information. Since the unit size is 'MinTransformSize' is the minimum transform unit size, a smaller value among them may be the minimum transform unit size 'CurrMinTuSize' possible in the current coding unit.
- the maximum transform unit size RootTuSize may vary depending on a prediction mode.
- RootTuSize may be determined according to the following relation (2).
- 'MaxTransformSize' represents the maximum transform unit size
- 'PUSize' represents the current prediction unit size.
- RootTuSize min (MaxTransformSize, PUSize) ......... (2)
- 'RootTuSize' which is a transform unit size when the transform unit split information is 0, may be set to a smaller value among the maximum transform unit size and the current prediction unit size.
- 'RootTuSize' may be determined according to Equation (3) below.
- 'PartitionSize' represents the size of the current partition unit.
- RootTuSize min (MaxTransformSize, PartitionSize) ........... (3)
- the conversion unit size 'RootTuSize' when the conversion unit split information is 0 may be set to a smaller value among the maximum conversion unit size and the current partition unit size.
- the current maximum conversion unit size 'RootTuSize' according to an embodiment that changes according to the prediction mode of the partition unit is only an embodiment, and a factor determining the current maximum conversion unit size is not limited thereto.
- the image data of the spatial domain is encoded for each coding unit of the tree structure, and the video decoding method based on the coding units of the tree structure.
- decoding is performed for each largest coding unit, and image data of a spatial region may be reconstructed to reconstruct a picture and a video that is a picture sequence.
- the reconstructed video can be played back by a playback device, stored in a storage medium, or transmitted over a network.
- the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.
- the computer-readable recording medium may include a storage medium such as a magnetic storage medium (eg, a ROM, a floppy disk, a hard disk, etc.) and an optical reading medium (eg, a CD-ROM, a DVD, etc.).
- the interlayer video encoding method and / or video encoding method described above with reference to FIGS. 1A to 19 will be referred to as a video encoding method of the present invention.
- the inter-layer video decoding method and / or video decoding method described above with reference to FIGS. 1A to 19 are referred to as the video decoding method of the present invention.
- a video encoding apparatus including the interlayer video encoding apparatus 10, the video encoding apparatus 100, or the image encoding unit 400 described above with reference to FIGS. 1A to 19 may be referred to as the “video encoding apparatus of the present invention”.
- the video decoding apparatus including the interlayer video decoding apparatus 20, the video decoding apparatus 200, or the image decoding unit 500 described above with reference to FIGS. 1A to 19 may be referred to as the video decoding apparatus of the present invention.
- a computer-readable storage medium in which a program is stored according to an embodiment of the present invention will be described in detail below.
- the disk 26000 described above as a storage medium may be a hard drive, a CD-ROM disk, a Blu-ray disk, or a DVD disk.
- the disk 26000 is composed of a plurality of concentric tracks tr, and the tracks are divided into a predetermined number of sectors Se in the circumferential direction.
- a program for implementing the above-described quantization parameter determination method, video encoding method, and video decoding method may be allocated and stored in a specific region of the disc 26000 which stores the program according to the above-described embodiment.
- a computer system achieved using a storage medium storing a program for implementing the above-described video encoding method and video decoding method will be described below with reference to FIG. 22.
- the computer system 26700 may store a program for implementing at least one of the video encoding method and the video decoding method of the present invention on the disc 26000 using the disc drive 26800.
- the program may be read from the disk 26000 by the disk drive 26800, and the program may be transferred to the computer system 26700.
- a program for implementing at least one of the video encoding method and the video decoding method may be stored in a memory card, a ROM cassette, and a solid state drive (SSD). .
- FIG. 22 illustrates the overall structure of a content supply system 11000 for providing a content distribution service.
- the service area of the communication system is divided into cells of a predetermined size, and wireless base stations 11700, 11800, 11900, and 12000 that serve as base stations are installed in each cell.
- the content supply system 11000 includes a plurality of independent devices.
- independent devices such as a computer 12100, a personal digital assistant (PDA) 12200, a camera 12300, and a mobile phone 12500 may be an Internet service provider 11200, a communication network 11400, and a wireless base station. 11700, 11800, 11900, and 12000 to connect to the Internet 11100.
- PDA personal digital assistant
- the content supply system 11000 is not limited to the structure shown in FIG. 24, and devices may be selectively connected.
- the independent devices may be directly connected to the communication network 11400 without passing through the wireless base stations 11700, 11800, 11900, and 12000.
- the video camera 12300 is an imaging device capable of capturing video images like a digital video camera.
- the mobile phone 12500 is such as Personal Digital Communications (PDC), code division multiple access (CDMA), wideband code division multiple access (W-CDMA), Global System for Mobile Communications (GSM), and Personal Handyphone System (PHS). At least one communication scheme among various protocols may be adopted.
- PDC Personal Digital Communications
- CDMA code division multiple access
- W-CDMA wideband code division multiple access
- GSM Global System for Mobile Communications
- PHS Personal Handyphone System
- the video camera 12300 may be connected to the streaming server 11300 through the wireless base station 11900 and the communication network 11400.
- the streaming server 11300 may stream and transmit the content transmitted by the user using the video camera 12300 through real time broadcasting.
- Content received from the video camera 12300 may be encoded by the video camera 12300 or the streaming server 11300.
- Video data captured by the video camera 12300 may be transmitted to the streaming server 11300 via the computer 12100.
- Video data captured by the camera 12600 may also be transmitted to the streaming server 11300 via the computer 12100.
- the camera 12600 is an imaging device capable of capturing both still and video images, like a digital camera.
- Video data received from the camera 12600 may be encoded by the camera 12600 or the computer 12100.
- Software for video encoding and decoding may be stored in a computer readable recording medium such as a CD-ROM disk, a floppy disk, a hard disk drive, an SSD, or a memory card that the computer 12100 may access.
- video data may be received from the mobile phone 12500.
- the video data may be encoded by a large scale integrated circuit (LSI) system installed in the video camera 12300, the mobile phone 12500, or the camera 12600.
- LSI large scale integrated circuit
- a user is recorded using a video camera 12300, a camera 12600, a mobile phone 12500, or another imaging device.
- the content is encoded and sent to the streaming server 11300.
- the streaming server 11300 may stream and transmit content data to other clients who have requested the content data.
- the clients are devices capable of decoding the encoded content data, and may be, for example, a computer 12100, a PDA 12200, a video camera 12300, or a mobile phone 12500.
- the content supply system 11000 allows clients to receive and play encoded content data.
- the content supply system 11000 enables clients to receive and decode and reproduce encoded content data in real time, thereby enabling personal broadcasting.
- the video encoding apparatus and the video decoding apparatus of the present invention may be applied to encoding and decoding operations of independent devices included in the content supply system 11000.
- the mobile phone 12500 is not limited in functionality and may be a smart phone that can change or expand a substantial portion of its functions through an application program.
- the mobile phone 12500 includes a built-in antenna 12510 for exchanging RF signals with the wireless base station 12000, and displays images captured by the camera 1530 or images received and decoded by the antenna 12510. And a display screen 12520 such as an LCD (Liquid Crystal Display) and an OLED (Organic Light Emitting Diodes) screen for displaying.
- the smartphone 12510 includes an operation panel 12540 including a control button and a touch panel. When the display screen 12520 is a touch screen, the operation panel 12540 further includes a touch sensing panel of the display screen 12520.
- the smart phone 12510 includes a speaker 12580 or another type of audio output unit for outputting voice and sound, and a microphone 12550 or another type of audio input unit for inputting voice and sound.
- the smartphone 12510 further includes a camera 1530 such as a CCD camera for capturing video and still images.
- the smartphone 12510 may be a storage medium for storing encoded or decoded data, such as video or still images captured by the camera 1530, received by an e-mail, or obtained in another form. 12570); And a slot 12560 for mounting the storage medium 12570 to the mobile phone 12500.
- the storage medium 12570 may be another type of flash memory such as an electrically erasable and programmable read only memory (EEPROM) embedded in an SD card or a plastic case.
- EEPROM electrically erasable and programmable read only memory
- FIG. 24 shows the internal structure of the mobile phone 12500.
- the power supply circuit 12700 the operation input controller 12640, the image encoder 12720, and the camera interface (12630), LCD control unit (12620), image decoding unit (12690), multiplexer / demultiplexer (12680), recording / reading unit (12670), modulation / demodulation unit (12660) and
- the sound processor 12650 is connected to the central controller 12710 through the synchronization bus 1730.
- the power supply circuit 12700 supplies power to each part of the mobile phone 12500 from the battery pack, thereby causing the mobile phone 12500 to operate. Can be set to an operating mode.
- the central controller 12710 includes a CPU, a read only memory (ROM), and a random access memory (RAM).
- the digital signal is generated in the mobile phone 12500 under the control of the central controller 12710, for example, the digital sound signal is generated in the sound processor 12650.
- the image encoder 12720 may generate a digital image signal, and text data of the message may be generated through the operation panel 12540 and the operation input controller 12640.
- the modulator / demodulator 12660 modulates a frequency band of the digital signal, and the communication circuit 12610 is a band-modulated digital signal. Digital-to-analog conversion and frequency conversion are performed on the acoustic signal.
- the transmission signal output from the communication circuit 12610 may be transmitted to the voice communication base station or the radio base station 12000 through the antenna 12510.
- the sound signal acquired by the microphone 12550 is converted into a digital sound signal by the sound processor 12650 under the control of the central controller 12710.
- the generated digital sound signal may be converted into a transmission signal through the modulation / demodulation unit 12660 and the communication circuit 12610 and transmitted through the antenna 12510.
- the text data of the message is input using the operation panel 12540, and the text data is transmitted to the central controller 12610 through the operation input controller 12640.
- the text data is converted into a transmission signal through the modulator / demodulator 12660 and the communication circuit 12610, and transmitted to the radio base station 12000 through the antenna 12510.
- the image data photographed by the camera 1530 is provided to the image encoder 12720 through the camera interface 12630.
- the image data photographed by the camera 1252 may be directly displayed on the display screen 12520 through the camera interface 12630 and the LCD controller 12620.
- the structure of the image encoder 12720 may correspond to the structure of the video encoding apparatus as described above.
- the image encoder 12720 encodes the image data provided from the camera 1252 according to the video encoding method of the present invention described above, converts the image data into compression-encoded image data, and multiplexes / demultiplexes the encoded image data. (12680).
- the sound signal obtained by the microphone 12550 of the mobile phone 12500 is also converted into digital sound data through the sound processor 12650 during recording of the camera 1250, and the digital sound data is converted into the multiplex / demultiplexer 12680. Can be delivered.
- the multiplexer / demultiplexer 12680 multiplexes the encoded image data provided from the image encoder 12720 together with the acoustic data provided from the sound processor 12650.
- the multiplexed data may be converted into a transmission signal through the modulation / demodulation unit 12660 and the communication circuit 12610 and transmitted through the antenna 12510.
- the signal received through the antenna converts the digital signal through a frequency recovery (Analog-Digital conversion) process .
- the modulator / demodulator 12660 demodulates the frequency band of the digital signal.
- the band demodulated digital signal is transmitted to the video decoder 12690, the sound processor 12650, or the LCD controller 12620 according to the type.
- the mobile phone 12500 When the mobile phone 12500 is in the call mode, the mobile phone 12500 amplifies a signal received through the antenna 12510 and generates a digital sound signal through frequency conversion and analog-to-digital conversion processing.
- the received digital sound signal is converted into an analog sound signal through the modulator / demodulator 12660 and the sound processor 12650 under the control of the central controller 12710, and the analog sound signal is output through the speaker 12580. .
- a signal received from the radio base station 12000 via the antenna 12510 is converted into multiplexed data as a result of the processing of the modulator / demodulator 12660.
- the output and multiplexed data is transmitted to the multiplexer / demultiplexer 12680.
- the multiplexer / demultiplexer 12680 demultiplexes the multiplexed data to separate the encoded video data stream and the encoded audio data stream.
- the encoded video data stream is provided to the video decoder 12690, and the encoded audio data stream is provided to the sound processor 12650.
- the structure of the image decoder 12690 may correspond to the structure of the video decoding apparatus as described above.
- the image decoder 12690 generates the reconstructed video data by decoding the encoded video data by using the video decoding method of the present invention described above, and displays the reconstructed video data through the LCD controller 1262 through the display screen 1252. ) Can be restored video data.
- video data of a video file accessed from a website of the Internet can be displayed on the display screen 1252.
- the sound processor 1265 may convert the audio data into an analog sound signal and provide the analog sound signal to the speaker 1258. Accordingly, audio data contained in a video file accessed from a website of the Internet can also be reproduced in the speaker 1258.
- the mobile phone 1250 or another type of communication terminal is a transmitting / receiving terminal including both the video encoding apparatus and the video decoding apparatus of the present invention, a transmitting terminal including only the video encoding apparatus of the present invention described above, or the video decoding apparatus of the present invention. It may be a receiving terminal including only.
- FIG. 25 illustrates a digital broadcasting system employing a communication system, according to various embodiments.
- the digital broadcasting system according to the embodiment of FIG. 25 may receive a digital broadcast transmitted through a satellite or terrestrial network using the video encoding apparatus and the video decoding apparatus.
- the broadcast station 12890 transmits the video data stream to the communication satellite or the broadcast satellite 12900 through radio waves.
- the broadcast satellite 12900 transmits a broadcast signal, and the broadcast signal is received by the antenna 12860 in the home to the satellite broadcast receiver.
- the encoded video stream may be decoded and played back by the TV receiver 12610, set-top box 12870, or other device.
- the playback device 12230 can read and decode the encoded video stream recorded on the storage medium 12020 such as a disk and a memory card.
- the reconstructed video signal may thus be reproduced in the monitor 12840, for example.
- the video decoding apparatus of the present invention may also be mounted in the set-top box 12870 connected to the antenna 12860 for satellite / terrestrial broadcasting or the cable antenna 12850 for cable TV reception. Output data of the set-top box 12870 may also be reproduced by the TV monitor 12880.
- the video decoding apparatus of the present invention may be mounted on the TV receiver 12810 instead of the set top box 12870.
- An automobile 12920 with an appropriate antenna 12910 may receive signals from satellite 12800 or radio base station 11700.
- the decoded video may be played on the display screen of the car navigation system 12930 mounted on the car 12920.
- the video signal may be encoded by the video encoding apparatus of the present invention and recorded and stored in a storage medium.
- the video signal may be stored in the DVD disk 12960 by the DVD recorder, or the video signal may be stored in the hard disk by the hard disk recorder 12950.
- the video signal may be stored in the SD card 12970. If the hard disk recorder 12950 includes the video decoding apparatus of the present invention according to an embodiment, the video signal recorded on the DVD disk 12960, the SD card 12970, or another type of storage medium is output from the monitor 12880. Can be recycled.
- the vehicle navigation system 12930 may not include the camera 1530, the camera interface 12630, and the image encoder 12720 of FIG. 26.
- the computer 12100 and the TV receiver 12610 may not include the camera 1250, the camera interface 12630, and the image encoder 12720 of FIG. 26.
- 26 is a diagram illustrating a network structure of a cloud computing system using a video encoding apparatus and a video decoding apparatus, according to various embodiments.
- the cloud computing system of the present invention may include a cloud computing server 14100, a user DB 14100, a computing resource 14200, and a user terminal.
- the cloud computing system provides an on demand outsourcing service of computing resources through an information communication network such as the Internet at the request of a user terminal.
- service providers integrate the computing resources of data centers located in different physical locations into virtualization technology to provide users with the services they need.
- the service user does not install and use computing resources such as application, storage, operating system, and security in each user's own terminal, but services in virtual space created through virtualization technology. You can choose as many times as you want.
- a user terminal of a specific service user accesses the cloud computing server 14100 through an information communication network including the Internet and a mobile communication network.
- the user terminals may be provided with a cloud computing service, particularly a video playback service, from the cloud computing server 14100.
- the user terminal may be any electronic device capable of accessing the Internet, such as a desktop PC 14300, a smart TV 14400, a smartphone 14500, a notebook 14600, a portable multimedia player (PMP) 14700, a tablet PC 14800, and the like. It can be a device.
- the cloud computing server 14100 may integrate and provide a plurality of computing resources 14200 distributed in a cloud network to a user terminal.
- the plurality of computing resources 14200 include various data services and may include data uploaded from a user terminal.
- the cloud computing server 14100 integrates a video database distributed in various places into a virtualization technology to provide a service required by a user terminal.
- the user DB 14100 stores user information subscribed to a cloud computing service.
- the user information may include login information and personal credit information such as an address and a name.
- the user information may include an index of the video.
- the index may include a list of videos that have been played, a list of videos being played, and a stop time of the videos being played.
- Information about a video stored in the user DB 14100 may be shared among user devices.
- the playback history of the predetermined video service is stored in the user DB 14100.
- the cloud computing server 14100 searches for and plays a predetermined video service with reference to the user DB 14100.
- the smartphone 14500 receives the video data stream through the cloud computing server 14100, the operation of decoding the video data stream and playing the video may be performed by the operation of the mobile phone 12500 described above with reference to FIG. 24. similar.
- the cloud computing server 14100 may refer to a playback history of a predetermined video service stored in the user DB 14100. For example, the cloud computing server 14100 receives a playback request for a video stored in the user DB 14100 from a user terminal. If the video was being played before, the cloud computing server 14100 may have a streaming method different depending on whether the video is played from the beginning or from the previous stop point according to the user terminal selection. For example, when the user terminal requests to play from the beginning, the cloud computing server 14100 streams the video to the user terminal from the first frame. On the other hand, if the terminal requests to continue playing from the previous stop point, the cloud computing server 14100 streams the video to the user terminal from the frame at the stop point.
- the user terminal may include the video decoding apparatus as described above with reference to FIGS. 1A through 19.
- the user terminal may include the video encoding apparatus as described above with reference to FIGS. 1A through 20.
- the user terminal may include both the video encoding apparatus and the video decoding apparatus as described above with reference to FIGS. 1A through 19.
- FIGS. 20 through 26 various embodiments in which the video encoding method and the video decoding method described above with reference to FIGS. 1A through 19 are stored in a storage medium, or in which the video encoding apparatus and the video decoding apparatus are implemented in the device are illustrated in FIGS. It is not limited to.
Abstract
Description
H.8.5.2.2.5.2 Derivation process for illumination compensation parameters Inputs to this process are: a list curSampleList specifying the current samples, , a list refSampleList specifying the reference samples, a variable numSamples specifying the number of elements in curSampleList and refSampleList. a bit depth of samples, bitDepth. the size of the current luma coding block nCSl a variable cIdx specifying colour component index,(설명: cIdx가 0일경우에는 luma를 의미, cIdx가 0이 아닐 경우에는 chroma를 의미)Outputs of this process are: a variable icWeight specifying a weight for illumination compensation, a variable icOffset specifying a offset for illumination compensation, a variable icShift specifying a bit shift for illumination compensation.The variable icWeight is set equal to 1, the variable icOffset is set equal to 0, and the variable icShift is set equal to 0. If cIdx is not equal to 0, the following applies:(설명: 아래가 offset parameter만 사용하는 IC model) The variables sumRef, sumCur are set equal to 0 and the following applies for i ranging from 0 to numSamples - 1, inclusive. sumRef += refSampleList[ i ] (H 176) sumCur += curSampleList[ i ] (H 177) The variable avgShift and avgOffset specifying the bit shift and offset needed for averaging are derived as avgShift = Ceil( Log2( numSamples ) ) (H 186) avgOffset = 1 << ( avgShift - 1 ) (H 187) The variable icOffset specifying an offset for illumination compensation is derived as: icOffset = ( psSumCur - psSumRef + avgOffset ) >> avgShift (H 202) Otherwise (if cIdx is equal to 0), the following applies:(설명: 아래가 scale factor 및 offset parameter를 모두 사용하는 IC model) The variables sumRef, sumCur, sumRefSquare and sumProdRefCur are set equal to 0 and the following applies for i ranging from 0 to numSamples - 1, inclusive. sumRef += refSampleList[ i ] (H 176) sumCur += curSampleList[ i ] (H 177) sumRefSquare += ( refSampleList[ i ] * refSampleList[ i ] ) (H 178) sumProdRefCur += ( refSampleList[ i ] * curSampleList[ i ] ) (H 179) The variables precShift and precOffset specifying the bit shift and offset needed to restrict precision to 16 bit are derived as precShift = Max( 0, bitDepth + Log2( nCSl) - 14 ) (H 180) precOffset = 1 << ( precShift - 1 ) (H 181) The variables psSumRef, psSumCur, psSumRefSquare and psSumProdRefCur are derived as psSumRef = ( precShift > 0 ) ? (sumRef + precOffset) >> precShift: sumRef (H 182) psSumCur = ( precShift > 0 ) ? (sumCur + precOffset ) >> precShift : sumCur (H 183) psSumRefSquare = ( precShift > 0 ) ? (sumRefSquare + precOffset ) >> precShift : sumRefSquare (H 184) psSumProdRefCur = ( precShift > 0 ) ? (sumProdRefCur + precOffset ) >> precShift : sumProdRefCur (H 185) The variable avgShift and avgOffset specifying the bit shift and offset needed for averaging are derived as avgShift = Ceil( Log2( numSamples ) ) - precShift (H 186) avgOffset = 1 << ( avgShift - 1 ) (H 187) When avgShift is equal to 0 the whole derivation process specified in this subclause terminates.. The variables numerDiv and denomDiv specifying numerator and denominator of a following divisions are derived as. numerDiv= ( psSumProdRefCur << avgShift ) - psSumRef * psSumCur (H 188) denomDiv= ( psSumRefSquare << avgShift ) - psSumRef * psSumRef (H 189) The variables psShiftNumer and psShiftDenom specifying the bit shifts to restrict the precision of numerDiv and denomDiv to 15 bit and 6 bit, respectively are derived as psShiftNumer = Max( 0, Floor( Log2( Abs( numerDiv ) ) ) - 14) (H 190) psShiftDenom = Max( 0, Floor( Log2( Abs( denomDiv ) ) ) - 5) (H 191) The variables psNumerDiv and psDenomDiv are derived as psNumerDiv = numerDiv >> psShiftNumer (H 192) psDenomDiv = denomDiv >> psShiftDenom (H 193) The variable psIcWeight specifying the shifted weight for illumination compensation is derived as specified in the following. If psDenomDiv is greater than 0, the following applies, The value of variable divCoeff is derived from Table H 11 depending on psDenomDiv. The value of psIcWeight is derived as psIcWeight = psNumerDiv * divCoeff (H 194) Otherwise( psDenomDiv is less or equal to 0), psIcWeight is set equal to 0. The variable icShift specifying a bit shift for illumination compensation is set equal to 13. The variable invPsShift specifying the number of bits needed to shift psIcWeight back to a range of 16 bit precision is derived as invPsShift = psShiftDenom - psShiftNumer + 15 - icShift (H 195) The variable invPsIcWeight specifying a weight for illumination compensation with 16 bit precision is derived as specified in the following If invPsShift is less than 0, the following applies: invPsIcWeight = Clip3( psIcWeight << ( Abs( invPsShift ) ), -2^15, 2^15-1) (H 196)Otherwise, ( invPsIcWeight is greater than or equal to 0), the following applies: invPsIcWeight = Clip3( psIcWeight >> ( Abs( invPsShift ) ), -2^15, 2^15 - 1 ) (H 197) The variable icWeight specifying a weight for illumination compensation with 7 bit precision is derived as specified in the following: If invPsIcWeight is greater than or equal to -26 and less than 26, the following applies. icWeight = invPsIcWeight (H 198) Otherwise, ( invPsIcWeight is less than -26 or greater than or equal to 26 ), the following applies. decIcShift = Max( 0, Floor(Log2( Abs( icWeight ) ) - 5 ) ) (H 199) icWeight = invPsIcWeight >> decIcShift (H 200) icShift -= decIcShift (H 201) The variable icOffset specifying an offset for illumination compensation is derived as: icOffset = (psSumCur - ((icWeight*psSumRef) >> icShift) + avgOffset) >> avgShift |
H.8.5.2.2.5.2 Derivation process for illumination compensation parameters Inputs to this process are:- a list curSampleList specifying the current samples, ,- a list refSampleList specifying the reference samples,- a variable numSamples specifying the number of elements in curSampleList and refSampleList.- a bit depth of samples, bitDepth.- the size of the current luma coding block nCSl - a variable cIdx specifying colour component index,(설명: cIdx가 0일경우에는 luma를 의미, cIdx가 0이 아닐 경우에는 chroma를 의미)- a variable isOffset specifying illumination compensation mode.(설명: 블록 모드가 view synthesis prediction mode일 경우 isOffset이 1로 setting 그 외의 모드에서는 0으로 setting)Outputs of this process are:- a variable icWeight specifying a weight for illumination compensation, - a variable icOffset specifying a offset for illumination compensation,- a variable icShift specifying a bit shift for illumination compensation.The variable icWeight is set equal to 1, the variable icOffset is set equal to 0, and the variable icShift is set equal to 0. If DepthFlag is equal to 1, isOffset is equal to 1 or cIdx is not equal to 0, the following applies:(설명: DepthFlag는 현재 picture가 depth이면 1로, 그렇지 않으면 0으로 설정)(설명: 아래가 offset parameter만 사용하는 IC model)- The variables sumRef, sumCur are set equal to 0 and the following applies for i ranging from 0 to numSamples -1, inclusive. sumRef += refSampleList[ i ] (H 176) sumCur += curSampleList[ i ] (H 177)- The variable avgShift and avgOffset specifying the bit shift and offset needed for averaging are derived as avgShift = Ceil( Log2( numSamples ) ) (H 186) avgOffset = 1 << ( avgShift - 1 ) (H 187)- The variable icOffset specifying an offset for illumination compensation is derived as: icOffset = ( psSumCur - psSumRef + avgOffset ) >> avgShift (H 202) Otherwise (if DepthFlag is equal to 0, isOffset is equal to 0 and cIdx is equal to 0), the following applies:(설명: 아래가 scale factor 및 offset parameter를 모두 사용하는 IC model)- The variables sumRef, sumCur, sumRefSquare and sumProdRefCur are set equal to 0 and the following applies for i ranging from 0 to numSamples - 1, inclusive. sumRef += refSampleList[ i ] (H 176) sumCur += curSampleList[ i ] (H 177) sumRefSquare += ( refSampleList[ i ] * refSampleList[ i ] ) (H 178) sumProdRefCur += ( refSampleList[ i ] * curSampleList[ i ] ) (H 179)- The variables precShift and precOffset specifying the bit shift and offset needed to restrict precision to 16 bit are derived as precShift = Max( 0, bitDepth + Log2( nCSl) - 14 ) (H 180) precOffset = 1 << ( precShift - 1 ) (H 181)- The variables psSumRef, psSumCur, psSumRefSquare and psSumProdRefCur are derived as psSumRef = ( precShift > 0 ) ? (sumRef + precOffset) >> precShift: sumRef (H 182) psSumCur = ( precShift > 0 ) ? (sumCur + precOffset ) >> precShift : sumCur (H 183) psSumRefSquare = ( precShift > 0 ) ? (sumRefSquare + precOffset ) >> precShift : sumRefSquare (H 184) psSumProdRefCur = ( precShift > 0 ) ? (sumProdRefCur + precOffset ) >> precShift : sumProdRefCur (H 185) - The variable avgShift and avgOffset specifying the bit shift and offset needed for averaging are derived as avgShift = Ceil( Log2( numSamples ) ) - precShift (H 186) avgOffset = 1 << ( avgShift - 1 ) (H 187)- When avgShift is equal to 0 the whole derivation process specified in this subclause terminates.. - The variables numerDiv and denomDiv specifying numerator and denominator of a following divisions are derived as. numerDiv= ( psSumProdRefCur << avgShift ) - psSumRef * psSumCur (H 188) denomDiv= ( psSumRefSquare << avgShift ) - psSumRef * psSumRef (H 189) - The variables psShiftNumer and psShiftDenom specifying the bit shifts to restrict the precision of numerDiv and denomDiv to 15 bit and 6 bit, respectively are derived as psShiftNumer = Max( 0, Floor( Log2( Abs( numerDiv ) ) ) - 14) (H 190) psShiftDenom = Max( 0, Floor( Log2( Abs( denomDiv ) ) ) - 5) (H 191)- The variables psNumerDiv and psDenomDiv are derived as psNumerDiv = numerDiv >> psShiftNumer (H 192) psDenomDiv = denomDiv >> psShiftDenom (H 193)- The variable psIcWeight specifying the shifted weight for illumination compensation is derived as specified in the following. - If psDenomDiv is greater than 0, the following applies, - The value of variable divCoeff is derived from Table H 11 depending on psDenomDiv. - The value of psIcWeight is derived as psIcWeight = psNumerDiv * divCoeff (H 194) - Otherwise( psDenomDiv is less or equal to 0), psIcWeight is set equal to 0. - The variable icShift specifying a bit shift for illumination compensation is set equal to 13. - The variable invPsShift specifying the number of bits needed to shift psIcWeight back to a range of 16 bit precision is derived as invPsShift = psShiftDenom - psShiftNumer + 15 - icShift (H 195)- The variable invPsIcWeight specifying a weight for illumination compensation with 16 bit precision is derived as specified in the following - If invPsShift is less than 0, the following applies: invPsIcWeight = Clip3( psIcWeight << ( Abs( invPsShift ) ), -2^15, 2^15 - 1 ) (H 196) - Otherwise, ( invPsIcWeight is greater than or equal to 0), the following applies: invPsIcWeight = Clip3( psIcWeight >> ( Abs( invPsShift ) ), -2^15, 2^15 - 1 ) (H 197)- The variable icWeight specifying a weight for illumination compensation with 7 bit precision is derived as specified in the following: - If invPsIcWeight is greater than or equal to -2^6 and less than 2^6, the following applies. icWeight = invPsIcWeight (H 198) - Otherwise, ( invPsIcWeight is less than -2^6 or greater than or equal to 2^6 ), the following applies. decIcShift = Max( 0, Floor(Log2( Abs( icWeight ) ) - 5 ) ) (H 199) icWeight = invPsIcWeight >> decIcShift (H 200) icShift -= decIcShift (H 201)- The variable icOffset specifying an offset for illumination compensation is derived as: icOffset = ( psSumCur - ( ( icWeight*psSumRef ) >> icShift ) + avgOffset ) >> avgShift (H 202) |
I.8.5.3.3.6.1 Derivation process for illumination compensation mode availability and parameters…3. .If puIvPredFlagLX is equal to 0, the variable puIcFlagLX is set equal to 0, otherwise (puIvPredFlagLX is equal to 1 ) the following applies: - The luma location (xRLX, yRLX) specifying the top-left sample of the reference block in refPicLX is derived as xRLX = xC + ( ( mvLX[ 0 ] + ( cIdx ? 4 : 2 ) ) >> ( 2 + ( cIdx ? 1 : 0 ) ) ) (I 198) yRLY = yC + ( ( mvLX[ 1 ] + ( cIdx ? 4 : 2 ) ) >> ( 2 + ( cIdx ? 1 : 0 ) ) ) (I 199) - The variable availFlagAboveRowLX specifying whether the above neighbouring row samples of the current block and the reference block are available is derived as specified in the following: availFlagAboveRowLX = availFlagCurAboveRow (I 200) - The variable availFlagLeftColLX specifying whether the left neighbouring column samples of the current block and the reference block are available is derived as specified in the following: availFlagLeftColLX = availFlagCurLeftCol (I 201) - The variable puIcFlagLX is derived as follows: puIcFlagLX = availFlagAboveRowLX | | availFlagLeftColLX (I 202)…2. The lists curNeighSampleListLX and refNeighSampleListLX specifying the neighbouring samples in the current picture and the reference picture are derived as specified in the following: - The variable numNeighSamplesLX specifying the number of elements in curNeighSampleListLX and in refNeighSampleLX is set equal to 0. - The variable leftNeighOffLX specifying the offset of the left neighbouring samples in curNeighSampleListLX and refNeighSampleLX is derived as leftNeighOffLX = availFlagAboveRowLX ? 0 : nCS (I 204) - For i ranging from 0 to nCS - 1, inclusive the following applies: - When availFlagAboveRowLX is equal to 1 the following applies: xP = Clip3( 0, pic_width_in_luma_samples - 1, xRLX + i ) yP = Clip3( 0, pic_height_in_luma_samples - 1, yRLY - 1 ) curNeighSampleListLX[ i ] = curRecSamples[ xC + i][ yC - 1 ] (I 205) refNeighSampleListLX[ I ] = refRecSamples[ xP ][ yP ] (I 206) numNeighSamplesLX += 1 (I 207) - When availFlagLeftColLX is equal to 1 the following applies: xP = Clip3( 0, pic_width_in_luma_samples - 1, xRLX - 1 ) yP = Clip3( 0, pic_height_in_luma_samples - 1, yRLY + i) curNeighSampleListLX[ i + leftNeighOffLX ] = curRecSamples[ xC - 1][ yC + i ] (I 208) refNeighSampleListLX[ i + leftNeighOffLX ] = refRecSamples[ xP][ yP ] (I 209)numNeighSamplesLX += 1 (I 210)… |
분할 정보 0 (현재 심도 d의 크기 2Nx2N의 부호화 단위에 대한 부호화) | 분할 정보 1 | ||||
예측 모드 | 파티션 타입 | 변환 단위 크기 | 하위 심도 d+1의 부호화 단위들마다 반복적 부호화 | ||
인트라 인터스킵 (2Nx2N만) | 대칭형 파티션 타입 | 비대칭형 파티션 타입 | 변환 단위 분할 정보 0 | 변환 단위 분할 정보 1 | |
2Nx2N2NxNNx2NNxN | 2NxnU2NxnDnLx2NnRx2N | 2Nx2N | NxN (대칭형 파티션 모드) N/2xN/2 (비대칭형 파티션 모드) |
Claims (15)
- 인터 레이어 비디오 복호화 방법에 있어서,제1 레이어 비트스트림으로부터 획득된 부호화 정보에 기초하여 제1 레이어 영상을 복원하는 단계;제2 레이어 비트스트림으로부터 획득된 인터 레이어 예측정보와 제1 레이어 복원 영상 중에서 복원될 제2 레이어 현재블록에 대응하는 제1 레이어 참조블록을 이용하여 제2 레이어 현재블록을 복원하는 단계;상기 제1 레이어 참조블록에 대해 적용할 휘도 보상 모델을 선택하고 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 단계; 및상기 휘도 보상 파라미터를 이용하여 상기 제1레이어 참조블록의 휘도를 보상하고 상기 제2레이어 현재블록을 포함하는 제2레이어 영상을 복원하는 단계를 포함하고,상기 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 단계는 상기 제2레이어 현재블록의 컬러 성분, 상기 제2레이어 현재블록을 포함하고 있는 픽처의 유형 정보, 상기 제2레이어 현재블록의 예측 모드 중 적어도 어느 하나에 기초하여 결정하는 것을 특징으로 하는 인터 레이어 비디오 복호화 방법.
- 제1항에 있어서, 상기 휘도 보상 모델을 선택하고 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 단계는,스케일 팩터와 제1오프셋을 결정하여, 상기 제1레이어 참조 블록의 각 화소값에 상기 스케일 팩터를 곱한 결과에 상기 오프셋을 더하여 상기 제1레이어 참조 블록의 휘도를 보상하는 제1휘도 보상 모델 또는제2오프셋을 결정하여 상기 제1레이어 참조 블록의 각 화소값에 상기 제2오프셋만을 더하여 상기 제1레이어 참조블록의 휘도를 보상하는 제2휘도 보상 모델 중 어느 하나를 선택하는 단계;상기 제1휘도 보상 모델이 선택되면 상기 스케일 팩터와 상기 제1오프셋을 결정하는 단계; 및상기 제2 휘도 보상 모델이 선택되면 상기 제2오프셋을 결정하는 단계를 포함하는 인터 레이어 비디오 복호화 방법.
- 제2항에 있어서, 상기 휘도 보상 모델을 선택하는 단계는,상기 제2레이어 현재블록의 컬러 성분이 루마(luma)이면 상기 제1휘도 보상 모델을 선택하고, 상기 제2레이어 현재블록의 컬러 성분이 크로마(chroma)이면 상기 제2휘도 보상 모델을 선택하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 복호화 방법.
- 제2항에 있어서, 상기 휘도 보상 모델을 선택하는 단계는,상기 제2레이어 현재블록이 텍스처(texture) 픽처 내부의 블록이면 상기 제1휘도 보상 모델을 선택하고, 상기 제2레이어 현재블록이 깊이 맵(depth map) 픽처 내부의 블록이면 상기 제2휘도 보상 모델을 선택하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 복호화 방법.
- 제2항에 있어서, 상기 휘도 보상 모델을 선택하는 단계는,상기 제2레이어 현재블록의 예측모드가 뷰 합성 예측 모드(View synthesis prediction mode)가 아니면 상기 제1휘도 보상 모델을 선택하고, 상기 제2레이어 현재블록의 예측 모드가 뷰 합성 예측 모드이면 상기 제2휘도 보상 모델을 선택하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 복호화 방법.
- 제2항에 있어서, 상기 휘도 보상 모델을 선택하는 단계는,제2레이어 현재블록의 컬러 성분이 크로마일 조건, 상기 제2레이어 현재블록이 깊이 맵 픽처 내부의 블록일 조건, 상기 제2레이어 현재 블록의 예측 모드가 뷰 합성 예측 모드일 조건 중 어느 하나의 조건을 만족하면 상기 제2휘도 보상 모델을 선택하고,상기 어느 조건에도 해당하지 않으면 제1휘도 보상 모델을 선택하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 복호화 방법.
- 인터 레이어 비디오 복호화 방법에 있어서,제1 레이어 비트스트림으로부터 획득된 부호화 정보에 기초하여 제1 레이어 영상을 복원하는 단계;제2 레이어 비트스트림으로부터 획득된 인터 레이어 예측정보와 제1 레이어 복원 영상 중에서 복원될 제2 레이어 현재블록에 대응하는 제1 레이어 참조블록을 이용하여 제2 레이어 현재블록을 복원하는 단계;상기 제1 레이어 참조블록에 대해 적용할 휘도 보상 파라미터를 결정하는 단계; 및상기 휘도 보상 파라미터를 이용하여 상기 제1레이어 참조블록의 휘도를 보상하여 상기 제2레이어 현재블록을 포함하는 제2레이어 영상을 복원하는 단계를 포함하고,상기 휘도 보상 파라미터를 결정하는 단계는 상기 제1레이어 참조블록이 상기 제1레이어 복원 영상의 경계를 벗어나면, 벗어난 영역 및 상기 벗어난 영역의 주변 화소들을 상기 제 1레이어 복원 영상의 경계 내부에 존재하는 화소들로 대체하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 복호화 방법.
- 제7항에 있어서, 상기 대체하는 단계는,상기 제1레이어 복원 영상의 경계로부터 상기 제1레이어 참조블록의 경계 바깥까지 상기 제1레이어 영상의 경계에 존재하는 화소값으로 대체하여 패딩(padding)하는 단계를 포함하는 인터 레이어 비디오 복호화 방법.
- 인터 레이어 비디오 부호화 방법에 있어서,제1 레이어 영상을 부호화하여 생성된 부호화 정보를 포함하는 제1 레이어 비트스트림을 생성하는 단계;제1 레이어 복원 영상 중에서 복원될 제2 레이어 현재블록에 대응하는 제1 레이어 참조블록을 이용하여 제2 레이어 현재블록을 복원하는 단계;상기 제1 레이어 참조블록에 대해 적용할 휘도 보상 모델을 선택하고 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 단계; 및상기 휘도 보상 파라미터를 이용하여 휘도 보상된 상기 제1 레이어 참조블록과 상기 제2 레이어 현재블록 간의 인터 레이어 예측정보를 포함하는 제2 레이어 비트스트림을 생성하는 단계를 포함하고,상기 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 단계는 상기 제2레이어 현재블록의 컬러 성분, 상기 제2레이어 현재블록을 포함하고 있는 픽처의 유형 정보, 상기 제2레이어 현재블록의 예측 모드 중 적어도 어느 하나에 기초하여 결정하는 것을 특징으로 하는 것을 특징으로 하는 인터 레이어 비디오 부호화 방법.
- 제9항에 있어서, 상기 휘도 보상 파라미터를 결정하는 단계는,스케일 팩터와 제1오프셋을 결정하여, 제1레이어 참조 블록의 각 화소값에 상기 스케일 팩터를 곱한 결과에 상기 오프셋을 더하여 상기 제1레이어 참조 블록의 휘도를 보상하는 제1휘도 보상 모델 또는제2오프셋을 결정하여 상기 제1레이어 참조 블록의 각 화소값에 상기 제2오프셋만을 더하여 상기 제1레이어 참조블록의 휘도를 보상하는 제2휘도 보상 모델 중 어느 하나를 선택하는 단계;상기 제1휘도 보상 모델이 선택되면 상기 스케일 팩터와 상기 제1오프셋을 결정하는 단계; 및상기 제2휘도 보상 모델이 선택되면 상기 제2오프셋을 결정하는 단계를 포함하는 인터 레이어 비디오 부호화 방법.
- 제10항에 있어서, 상기 휘도 보상 모델을 선택하는 단계는,제2레이어 현재블록의 컬러 성분이 크로마일 조건, 상기 제2레이어 현재블록이 깊이 맵 픽처 내부의 블록일 조건, 상기 제2레이어 현재블록의 예측 모드가 뷰 합성 예측 모드일 조건 중 어느 하나의 조건을 만족하면 상기 제2휘도 보상 모델을 선택하고,상기 어느 조건에도 해당하지 않으면 제1휘도 보상 모델을 선택하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 부호화 방법.
- 인터 레이어 비디오 부호화 방법에 있어서,제1 레이어 비트스트림으로부터 획득된 부호화 정보에 기초하여 제1 레이어 영상을 복원하는 단계;제2 레이어 비트스트림으로부터 획득된 인터 레이어 예측정보와 제1 레이어 복원 영상 중에서 복원될 제2 레이어 현재블록에 대응하는 제1 레이어 참조블록을 이용하여 제2 레이어 현재블록을 복원하는 단계;상기 제1 레이어 참조블록에 대해 적용할 휘도 보상 파라미터를 결정하는 단계; 및상기 휘도 보상 파라미터를 이용하여 상기 제1레이어 참조블록의 휘도를 보상하여 상기 제2레이어 현재블록을 포함하는 제2레이어 영상을 복원하는 단계를 포함하고,상기 휘도 보상 파라미터를 결정하는 단계는 상기 제1레이어 참조블록이 상기 제1레이어 복원 영상의 경계를 벗어나면, 벗어난 영역 및 상기 벗어난 영역의 주변 화소들을 상기 제 1레이어 복원 영상의 경계 내부에 존재하는 화소들로 대체하는 단계를 포함하는 것을 특징으로 하는 인터 레이어 비디오 부호화 방법.
- 제12항에 있어서, 상기 대체하는 단계는,상기 제1레이어 복원 영상의 경계로부터 상기 제1레이어 참조블록의 경계 바깥까지 상기 제1레이어 영상의 경계에 존재하는 화소값으로 대체하여 패딩(padding)하는 단계를 포함하는 인터 레이어 비디오 부호화 방법.
- 인터 레이어 비디오 복호화 장치에 있어서,제1 레이어 비트스트림으로부터 획득된 부호화 정보에 기초하여 제1 레이어 영상을 복원하는 제1레이어 복호화부;제2 레이어 비트스트림으로부터 획득된 인터 레이어 예측정보와 제1 레이어 복원 영상 중에서 복원될 제2 레이어의 현재블록에 대응하는 제1 레이어 참조블록을 이용하여 제2 레이어 현재블록을 복원하는 제2레이어 복호화부;상기 제1 레이어 참조블록에 대해 적용할 휘도 보상 모델을 선택하고 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 휘도보상 결정부를 포함하고,상기 휘도 보상 결정부는 상기 제2레이어 현재블록의 컬러 성분, 상기 제2레이어 현재블록을 포함하고 있는 픽처의 유형 정보, 상기 제2레이어 현재블록의 예측 모드 중 적어도 어느 하나에 기초하여 상기 휘도 보상 파라미터를 결정하고,상기 제2레이어 복호화부는 상기 휘도 보상 파라미터를 이용하여 상기 제1레이어 참조블록의 휘도를 보상하고 상기 제2레이어 현재블록을 포함하는 제2레이어 영상을 복원하는 인터 레이어 비디오 복호화 장치.
- 인터 레이어 비디오 부호화 장치에 있어서,제1 레이어 영상을 부호화하여 생성된 부호화 정보를 포함하는 제1 레이어 비트스트림을 생성하는 제1레이어 부호화부;제2 레이어 현재블록을 복원하기 위해, 제1 레이어 복원 영상 중에서 복원될 제2 레이어 현재블록에 대응하는 제1 레이어 참조블록을 이용하여 복원되는 제2 레이어 현재블록을 복원하는 제2 레이어 부호화부; 및상기 제1 레이어 참조블록에 대해 적용할 휘도 보상 모델을 선택하고 선택된 상기 휘도 보상 모델에 대한 휘도 보상 파라미터를 결정하는 휘도보상 결정부를 포함하고,상기 휘도 보상 결정부는 상기 제2레이어 현재블록의 컬러 성분, 상기 제2레이어 현재블록을 포함하고 있는 픽처의 유형 정보, 상기 제2레이어 현재 블록의 예측 모드 중 적어도 어느 하나에 기초하여 휘도 보상 파라미터를 결정하고,상기 제2레이어 부호화부는상기 휘도 보상 파라미터를 이용하여 휘도 보상된 상기 제1 레이어 참조블록과 상기 제2 레이어 현재블록 간의 인터 레이어 예측정보를 포함하는 제2 레이어 비트스트림을 생성하는 인터 레이어 비디오 부호화 장치.
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US10321142B2 (en) | 2019-06-11 |
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