KR20110068793A - Apparatus and method for video coding and decoding - Google Patents

Abstract

PURPOSE: An image encoding/decoding apparatus and method thereof are provided to efficiently predict an encoding parameter from a block within a slide in which a target block is included and to increase image compression performance. CONSTITUTION: A control unit determines a reference block for the prediction of an in-screen encoding parameter(S210). The control unit predicts the encoding parameter through the encoding parameter of the reference block(S220). The control unit performs entropy encoding about the encoding parameter through the encoding parameter of the reference block(S230).

Description

Apparatus and method for video encoding and decoding {APPARATUS AND METHOD FOR VIDEO CODING AND DECODING}

Associated with an image encoding apparatus and method, and more particularly with an apparatus and method using intra picture video encoding.

The invention of the Ministry of Knowledge Economy and ICT IT It is derived from the research conducted as part of the original technology development. [Task Management No.: 2008-F-011-01, Title: Next Generation DTV Core Technology Development- Glasses-free Individual Type 3 D broadcasting technology development].

An intra prediction mode prediction method, such as a most probable mode (MPM), uses an intra prediction mode of neighboring blocks of the encoding block to encode an intra prediction mode of the encoding block when encoding a specific block. Encode In the above method, the neighboring blocks are limited to only the neighboring blocks of the encoding target block in the current slice.

Among the entropy encoding methods, context adaptive binary arithmetic coding (CABAC) uses a bean (unit) context model to determine the codeword of the syntax. Encode In this case, the context model is limited to a neighboring block of the block to be encoded or to the block to be encoded.

According to one aspect of the invention, restoring the first block of the first slice, restoring the second block of the second slice, at least one block of the restored first block or the restored second block Determining as a reference block, predicting a coding parameter of a third block of the second slice based on the determined coding parameter of the reference block, based on the predicted coding parameter A predictive encoding method is provided that includes determining a code value for an encoding parameter and performing encoding of the third block based on the determined encoding parameter.

The slice may be a slide that is allowed to reference another slice.

The reference block may be determined using one or more of pixel value similarity between blocks, encoding parameter similarity between blocks, expression calculated from encoding parameter similarity between blocks, absolute position and relative position between blocks.

Encoding of the third block may be entropy encoding.

In the entropy coding, the coding parameter of the reference block may be used for probability model update and determination of the highest probability mode in an arithmetic coding scheme.

In the entropy coding, coding parameters of the reference block may be used for probability model updating, codeword table selection, and codeword selection in a variable length coding scheme.

According to another aspect of the present invention, a reference block for an encoding target block is determined by receiving data about a slice and blocks within the slice, and using the encoding parameter of the reference block, within or between screens of the encoding target block. A control unit for predicting an encoding parameter, performing entropy encoding on the intra-encoding parameter of the encoding target block, and a storage unit receiving data necessary for the operation of the control unit from the control unit and transmitting the data to the control unit; The reference block is provided with a prediction encoding apparatus selected from a reconstructed block in a slice including the encoding target block and a reconstructed block in an already reconstructed slice.

According to another aspect of the invention, the step of restoring the first block of the first slice, the step of restoring the second block of the second slice, at least one or more of the restored first block or the restored second block Determining a block as a reference block, predicting a decoding parameter of a third block of the second slice based on the determined decoding parameter of the reference block, and based on the predicted decoding parameter A predictive decoding method is provided that includes determining a code value for a decoding parameter of a block and performing decoding of the third block based on the determined decoding parameter.

In encoding an image, an encoding parameter used when a block is encoded in a picture is efficiently predicted from a previously reconstructed slice or a block present in a slice to which the target block belongs.

When intra picture prediction is used in an inter picture slice, an intra picture prediction mode may be used not only in blocks of the current slice but also in blocks of a reconstructed slice before the current slice when encoding the picture prediction mode.

When the intra-picture encoding is used in the inter-picture slice, the context model for each syntax may be extended to the previous slice as well as the current slice.

Image compression performance may be improved by efficiently determining a parameter of an encoding target block.

Image compression performance may be improved by efficiently predicting and encoding a parameter of an encoding target block.

1 shows an example of a slice and a block to be encoded.
2 illustrates an image encoding method according to an embodiment of the present invention.
3 illustrates an image encoding apparatus according to an embodiment of the present invention.
4 illustrates an image encoding method according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the embodiments. Like reference numerals in the drawings denote like elements.

1 shows an example of a slice and a block to be encoded.

In FIG. 1, the slice 110 to be encoded is shown. Portion 120, indicated by an oblique line, represents an area of an already restored block in the slice. The block 130 indicated by a solid line is a block to be encoded, and the block 140 indicated by a dotted line is a reference block.

The slice and the block may be the target of decryption.

2 illustrates an image encoding method according to an embodiment of the present invention.

The method according to the present embodiment may be performed on slices that are allowed to refer to other slices, such as P slices or B slices, for example.

In inter picture encoding slices (hereinafter referred to as inter picture slices) such as P slices or B slices, an intra picture / inter picture encoding mode is selectively used within one slice.

In the present embodiment, when intra-picture encoding is performed on an inter-picture slice, not only a block of a slice (hereinafter, referred to as a current slice) belonging to a block (hereinafter, referred to as a current block) that is a target of current encoding, but also a previous block The intra prediction mode may be used through the prediction from the block of the slice reconstructed at.

For example, when the intra-picture encoding is performed on an inter-picture slice, the present embodiment predictively encodes the current block by further using pixel values and encoding parameters in another slice that have already been reconstructed in addition to the reconstructed pixel values in the current slice. .

First, a referencing block for predicting an intra coding parameter of a current block is determined (S210).

The reference block includes at least one of already reconstructed first blocks of the current slice to which the current block belongs and second blocks of another slice already restored. (Hereinafter, blocks that are the targets of the reference block, that is, the first blocks and the second blocks are called target blocks.)

The reference block may be determined using pixel value similarity between the current block and the target block (or neighboring blocks of the target block). The pixel value similarity is measured by a method of measuring pixel value similarity between blocks generally used in image encoding such as sum of absolute differences (SAD), sum of absolute transformed difference (SATD), or sum of the squared differences (SSD). Can be.

The pixel value similarity may be determined as one to one between blocks.

The pixel value similarity may be determined to be many to one among blocks. At this time, the pixel value weight combination of the blocks and the pixel value of the other single block are compared.

The pixel value similarity may be determined to be many to many among blocks. In this case, the pixel value weight combinations of the plurality of blocks and the pixel value weight combinations of the plurality of other blocks are compared.

The determination of the reference block may be performed using coding parameter similarity between the current block and the target block.

The encoding parameter is information for encoding a picture, for example, an intra prediction mode, an inter prediction mode, a motion (motion) vector, a quantization parameter, Each of the embodiments of the block size, block partition information, macro block type, etc., statistical embodiments, and combined embodiments are included.

The similarity of the inter-block coding parameters means the sameness of prediction types (eg, in picture or between pictures), similarity in prediction direction, similarity in prediction mode, similarity in block size, and the like. When the blocks use the same intra prediction mode, use similar motion vectors, or use the same quantization parameter, the same block size, or the same block partition information, it is determined that the similarity of the encoding parameters is high between the blocks. Can be.

The encoding parameter similarity between the blocks may be determined through a combination of one or more parameters of the encoding parameters. The reference block may be determined using an equation calculated from encoding parameters of the target blocks.

A result obtained through a calculation using a combination of encoding parameters of the target blocks may be determined as an encoding parameter of a virtual block, and the virtual block may be the reference block.

The shifted intra prediction (DIP) determines a block having a high similarity between the current block and the pixel value among the reconstructed blocks of the current slice as a reference block, and determines the pixel value of the reference block as the reference block. This method is used as the pixel value.

Template matching (TM) determines a pixel value similarity between neighboring pixels of the reconstructed blocks of the current slice and neighboring pixels of the current block to determine a block having a high similarity in pixel value as a reference block. The pixel value of is used as the pixel value of the target block.

After a reference block is determined using the DIP or the TM to predict an encoding parameter, an encoding parameter of the reference block may be used when encoding an encoding target block.

In the present embodiment, the DIP or the TM may be used as it is in encoding the current block, and the reference block may be determined among the target blocks by using another method described above or below.

In the present embodiment, the current block may be encoded by using encoding parameters in the reference block as it is or encoding only a portion thereof as it is.

The reference block may be determined according to an absolute position in the image of the target block, and may be determined according to a position relative to the current block of the target block.

The relative position may be fixed in one slice, may be changed, and may also be changed in units of slices.

If the reference block in the current slice or the previous slice is an inter-picture coded block, the reference block is a block in another slice indicated by a motion vector or another reference block present at the same relative position or absolute position in the image with the reference block. This may be determined as the current reference block.

The reference block may be determined using at least one of the pixel value similarity, the coding parameter similarity, the calculated equation, the absolute position, and the relative position.

The reference block may be one or more, and one or more selected reference blocks may be signaled.

Next, an intra picture encoding parameter of the current block is predicted using the encoding parameter of the reference block (S220).

An intra-picture encoding parameter of the current block may be predicted or encoded through differential pulse code modulation (DPCM) between the encoding parameter value of the reference block and the encoding parameter value of the current block.

An intra-picture encoding parameter of the current block may be predicted by using the encoding parameter of the reference block as the encoding parameter value of the current block.

When the DIP is used in the present embodiment, the target block having the pixels most similar to the pixels in the current block may be determined as the reference block by using a block matching algorithm (BMA). The macroblock partition type, the intra prediction mode and the chrominance prediction mode of the determined reference block may be used as is for the current block.

In the present embodiment, when the TM is used, the pixel similarity between the neighboring pixels outside the current block and the neighboring pixels of the target block is determined by using a BMA to predict an intra coding parameter of the current block. The reference block can be determined by. The macroblock partition type, the intra prediction mode and the chrominance prediction mode of the determined reference block may be used as is for the current block.

An intra picture encoding parameter of the current block may be predicted from a weighted combination of encoding parameters of one or more reference blocks.

When there are a plurality of reference blocks, when a plurality of reference block sets are determined, an intra-picture encoding parameter of the current block may be predicted by using one reference block set among the plurality of reference block sets.

In this case, the used reference block set may be used for encoding a block to be subjected to prediction encoding later. Reference blocks included in the reference block set may be excluded from the set, or a reference block set update may be performed in which reference blocks not included in the set are added to the reference block set.

One or more of the intra picture encoding parameter prediction values may be determined, and the determined intra picture encoding parameter prediction values are signaled.

Next, entropy encoding is performed on the intra picture encoding parameter of the current block by using the encoding parameter of the reference block (S230).

The encoding parameter of the reference block is used for a context model in context-adaptive entropy encoding to perform entropy for the intra picture encoding parameter of the current block.

The coding parameter of the reference block may be updated to the probability model of the context model. In addition, the existing probabilistic model may continue to be used without updating the coding parameters of the reference block.

The probability model of the reference block in the previous slice can be used as it is. In addition, the probabilistic model of the reference block in the previous slice may be reflected in the probabilistic model of the current block to encode the encoding parameter of the current block.

The coding parameter of the reference block may be used for probability model update and determination of the highest likelihood mode in the context-adaptive arithmetic coding scheme. In addition, based on the update or the determination, entropy for the intra picture coding parameter of the current block may be performed.

The coding parameter of the reference block may be used for codeword table selection in a context-adaptive variable length coding scheme. In addition, entropy for an intra picture coding parameter of the current block may be performed based on the codeword table.

The method described above with reference to FIG. 2 may also be applied to an image decoding method.

In this case, the current block in the above-described method means a block that is the target of current decoding, and the current slice means a slice to which the current block belongs.

In addition, coding parameters correspond to decoding parameters, predictive coding corresponds to prediction decoding, coded blocks corresponds to decoded blocks, and entropy coding corresponds to entropy decoding, and context-adaptive arithmetic coding corresponds to context-adaptive arithmetic decoding. Variable length coding corresponds to context adaptive variable length decoding.

3 illustrates an image encoding apparatus according to an embodiment of the present invention.

The device 300 includes a controller 310, a storage 320, and a buffer 330.

The controller 310 receives a slice and data about blocks within the slice from the buffer 330 and the storage 320 to determine a reference block for a block to be encoded, and uses encoding parameters of the reference block. By predicting the intra picture encoding parameter of the encoding target block, entropy encoding is performed on the intra picture encoding parameter of the encoding object block. The controller 310 stores the data necessary for the above-described determination, the prediction, and the performance in the storage 320.

The storage 320 receives data necessary for the operation of the controller 310 from the controller 310. The storage unit 320 transmits the data stored at the request of the controller 310 to the controller 310.

On the other hand, the buffer 330 is a component according to an embodiment of the present invention that can be added to receive and store data about the slice and the blocks in the slice from the outside.

The buffer 330 provides the stored data to the controller 310.

The apparatus 300 described above with reference to FIG. 3 may also be used for image decoding.

In this case, the controller 310 receives data from the buffer 330 and the storage 320, and determines a reference block for a decoding target block, and determines a decoding parameter of the reference block. An intra prediction decoding parameter of the decoding object block is predicted by using, and entropy decoding is performed on the decoding parameter of the decoding object block. In addition, the controller 310 stores the data necessary for the above-described determination, the prediction, and the performance in the storage 320.

4 illustrates an image encoding method according to an embodiment of the present invention.

First, it is determined whether the restored slice exists (S410).

If the restored slice does not exist, the procedure ends.

If the restored slice exists, it is determined whether a restored block exists in the current slice (S420).

If a reconstructed block does not exist in the slice, it should be determined whether a reconstructed block exists for the previous or next slice. Therefore, step S410 in which it is determined whether the above-described restored slice exists is performed again for the previous or next slice.

If a reconstructed block exists in the slice, a reference block is determined among the reconstructed blocks.

In step S430, a reference block for the current block is determined. A specific embodiment of the step S430 has been described above with reference to step S210 of FIG. 1.

For example, if the current slice is the first slice, the reference block is selected from the blocks already restored within the first slice.

for example. If the current slice is the second slice and the current block is the first block in the slice, the reference block is selected from blocks already restored in the first slice.

For example, if the current slice is the second slice, the reference block is selected from blocks already restored in the first slice and blocks already restored in the second slice.

In step S440, the intra picture coding parameter of the current block is predicted. A specific embodiment of the step S440 has been described above with reference to step S220 of FIG. 1.

In step S450, entropy encoding is performed on an intra picture encoding parameter of the current block. A specific embodiment of the step S450 has been described above with reference to step S230 of FIG. 1.

When the work on the current block is completed, the prediction encoding on the next block in the current slice should be performed. Therefore, step S420, in which it is determined whether the above-described restored block exists, is performed again for the next block.

The method described above with reference to FIG. 4 may also be applied to an image decoding method. In this case, the encoding parameter in the aforementioned method corresponds to the decoding parameter, the entropy encoding corresponds to the entropy decoding, and the predictive encoding corresponds to the predictive decoding.

Method according to an embodiment of the present invention is implemented in the form of program instructions that can be executed by various computer means may be recorded on a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as CD-ROMs, DVDs, and magnetic disks, such as floppy disks. Magneto-optical media, and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine code generated by a compiler, but also high-level language code that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

310: control unit
320: storage unit
330: buffer

Claims (1)

Restoring a first block of the first slice;
Restoring a second block of the second slice;
Determining at least one block among the reconstructed first block or the reconstructed second block as a reference block;
Predicting an encoding parameter of a third block of the second slice based on the determined encoding parameter of the reference block; And
Performing encoding of the third block based on the predicted encoding parameter.
Predictive encoding method comprising a.

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