JP2016106444A - Moving image encoding apparatus and moving image encoding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moving image encoding apparatus that performs encoding by selecting a combination of plural block sizes to be subjected to inter-image prediction processing and plural block sizes to be subjected to orthogonal transform processing and that is capable of properly performing block size determination processing with a small amount of processing.SOLUTION: A moving image encoding apparatus 100 includes: an inter-image prediction processing unit 107 that generates a prediction image for each of blocks; a difference calculation unit 109 that generates a difference image for each of the blocks; and an orthogonal transform processing block size determination unit 103 that determines the block size to be subjected to orthogonal transform processing according to the magnitude of amplitude of pixel values of difference images associated with the plural blocks.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a moving image encoding apparatus that divides an input image into blocks and encodes them.

  In recent years, with the development of multimedia applications, it has become common to handle all media information such as images, sounds and texts in a unified manner. Also, since a digitized image has a huge amount of data, an image information compression technique is indispensable for storage and transmission. On the other hand, in order to interoperate compressed image data, standardization of compression technology is also important. For example, as a standard for image compression technology, ITU-T (International Telecommunication Union Telecommunication Standardization Sector) 261, H.H. 263, H.M. H.264, ISO / IEC (International Organization for Standardization) MPEG-1, MPEG-3, MPEG-4, MPEG-4AVC, and the like. At present, standardization activities for a next-generation video coding method called HEVC in cooperation with ITU-T and ISO / IEC are in progress.

  In such moving picture coding, each picture to be coded is divided into coding unit blocks, and the amount of information is compressed by reducing redundancy in the time direction and the spatial direction for each block. In inter-frame predictive coding for the purpose of reducing temporal redundancy, motion detection and prediction image generation are performed in units of blocks with reference to forward or backward pictures. Then, a difference image between the obtained predicted image and the block to be encoded is acquired. In addition, in the intra prediction encoding for the purpose of reducing spatial redundancy, a prediction image is generated from pixel information of surrounding encoded blocks, and the obtained prediction image and a block to be encoded are obtained. Get the difference image. Further, the amount of information is compressed by performing orthogonal transform processing such as discrete cosine transform and quantization processing on the obtained difference image and generating a code string using variable length coding and arithmetic coding.

  In HEVC (Non-Patent Document 1), as a unit for generating a prediction image in the above-described inter-screen prediction coding, any of eight block sizes such as 32 × 32 pixels, 16 × 32 pixels, and 16 × 16 pixels can be arbitrarily selected. You can select and use the size. A high block efficiency is realized by using a small block size for an image with a complex motion of the imaged object and a large block size for an image with a simple motion of the imaged object.

  In addition, an arbitrary size is selected from four types of block sizes of 32 × 32 pixels, 16 × 16 pixels, 8 × 8 pixels, and 4 × 4 pixels as a unit for performing the above-described orthogonal transform processing and quantization processing. Can be used. High encoding efficiency is achieved by using a small block size for images with different features in a fine range and using a large block size for images with similar features in a wide range.

JCTVC-L1003: High Efficiency Video Coding (HEVC) text specification draft 10 (01/2013)

  As described above, HEVC has eight types of block sizes as a unit for generating a predicted image in inter-screen predictive coding. Furthermore, there are four types of block sizes as units for performing orthogonal transform processing and quantization processing. Therefore, an enormous amount of processing is required to determine an optimal combination of block sizes from among the encoding processing.

  The present disclosure relates to a block size that is a unit for generating a prediction image in inter-frame prediction encoding and a block size that is a unit for performing orthogonal transform processing and quantization processing, for example, in a moving image encoding device using HEVC. A moving picture encoding apparatus capable of efficiently determining a combination with the above is provided with a small processing amount.

  A moving image encoding apparatus according to the present disclosure is a moving image encoding apparatus that generates a code string by encoding a coding target picture using a predetermined coding standard including inter-screen prediction processing, and A block dividing unit that outputs pixels constituting a picture for each output block having any one of a plurality of block sizes set in advance, and an output unit for pixels belonging to the output block An inter-screen prediction processing unit that sets a block for prediction processing having a block size equal to or smaller than the block size and generates a prediction image for each block for prediction processing; a prediction image generated for each block for prediction processing; A difference calculation unit that calculates a difference between pixels belonging to an output block corresponding to each of the prediction images and generates a difference image in units of blocks for prediction processing; (1) a first operation for setting a square block obtained by integrating adjacent prediction processing blocks as an orthogonal transform block based on a difference image belonging to an adjacent block among the blocks for 2) Dividing the block for prediction processing into a square shape, an orthogonal transform block size determining unit that executes a second operation of setting the block obtained by the division as a block for orthogonal transform, and the set orthogonal transform Each block includes a residual coefficient encoding unit that performs orthogonal transform and quantization processing to generate a residual coefficient.

  It should be noted that the present invention can be realized not only as such a moving picture coding apparatus, but also as a program or an integrated circuit that realizes processing equivalent to each means included in such a moving picture coding apparatus. You can also.

  The moving image encoding apparatus according to the present disclosure performs, for example, a block size that is a unit for generating a predicted image in inter-frame predictive encoding, orthogonal transform processing, and quantization processing in a moving image encoding device using HEVC. A combination with the unit block size can be determined efficiently with a small amount of processing.

The block diagram which shows the moving image encoder which concerns on embodiment of this invention The figure which shows the concept for demonstrating the combination of the block size used as a processing unit The flowchart which shows the orthogonal transformation block size determination process and residual coefficient encoding process which concern on embodiment of this invention The figure which shows the concept for demonstrating an example of the method of performing the determination using the pixel value of a difference image in orthogonal transformation block size determination processing The figure which shows the concept for demonstrating an example of the orthogonal transformation block size determined in embodiment of this invention The flowchart which shows another orthogonal transformation block size determination process and residual coefficient encoding process which concern on embodiment of this invention The flowchart which shows another orthogonal transformation block size determination process which concerns on embodiment of this invention, and a residual coefficient encoding process The figure which shows the concept for demonstrating another example of the method of performing the determination using the pixel value of a difference image in orthogonal transformation block size determination processing. The flowchart which shows another orthogonal transformation block size determination process which concerns on embodiment of this invention, and a residual coefficient encoding process The figure which shows the concept for demonstrating another example of the method of performing the determination using the pixel value of a difference image in orthogonal transformation block size determination processing.

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The inventor (s) provides the accompanying drawings and the following description in order for those skilled in the art to fully understand the present disclosure, and is intended to limit the subject matter described in the claims. Not what you want.

(Embodiment 1)
Hereinafter, Embodiment 1 will be described with reference to FIGS.

(Description of processing of the entire encoding device)
FIG. 1 is a block diagram of a video encoding apparatus 100 according to an embodiment of the present invention. The moving image encoding apparatus 100 divides an image input in units of pictures into blocks, performs encoding processing in units of blocks, and generates a code string.

  The moving picture encoding apparatus 100 includes a picture memory 101, a block dividing unit 102, an orthogonal transform block size determining unit 103, a residual coefficient encoding unit 104, a residual coefficient decoding unit 105, and a picture buffer 106. And an inter-screen prediction processing unit 107 and a code string generation unit 108.

  The picture memory 101 stores the input image signals input in units of pictures in the order of display by rearranging the pictures in the order of encoding. When the picture memory 101 receives a read command from the block dividing unit 102, the picture memory 101 outputs an input image signal related to the read command.

  The block division unit 102 outputs the pixels constituting the encoding target picture for each output block having one of a plurality of preset block sizes.

  Specifically, the block division unit 102 divides the input image signal input from the picture memory 101 into blocks called coding units (CUs) that are encoding processing units. FIG. 2 is a diagram showing selectable block sizes.

  As shown in FIG. 2, the CU can be selected from four block sizes ranging from 64 × 64 pixels to 8 × 8 pixels. In general, a small block size is selected in a region where the pixel value of the input image and the movement of the object are complex, and a large block size is selected in a region where the pixel value of the input image and the movement of the object are simple. Subsequent processing is performed in units of blocks of this CU.

  The inter-screen prediction processing unit 107 sets a prediction processing block having a block size equal to or smaller than the output block size for the pixels belonging to the output block, and generates a prediction image for each prediction processing block. Generate.

  Specifically, the inter-screen prediction processing unit 107 uses a reconstructed image signal of a past picture that has been encoded and stored in the picture buffer 106 based on the input image signal input from the block dividing unit 102. Inter-screen prediction processing. In the inter-screen prediction process, an area having a pixel configuration most similar to the pixel configuration of the input image is searched from the reconstructed image (motion search), and an area in the searched reconstructed image is predicted. Generate (motion compensation) as an image. At this time, motion compensation is performed in block units called prediction units (PUs) obtained by further dividing the CU unit block. FIG. 2 is a diagram showing selectable block sizes. As shown in FIG. 2, for example, when the CU has a block size of 32 × 32 pixels, the PU can be selected from eight block sizes of 32 × 32 pixels to 24 × 32 pixels. In general, a small block size is selected for an image with a complicated movement of the imaged object, and a large block size is selected for an image with a simple movement of the imaged object.

  The difference calculation unit 109 generates a difference image signal that is a difference value between the PU unit input image signal input from the block division unit 102 and the PU unit prediction image signal input from the inter-screen prediction processing unit 107. . The generated difference image signal is output to the orthogonal transform block size determination unit 103.

  The orthogonal transform block size determination unit 103 performs orthogonal transform on a square block obtained by integrating (1) adjacent prediction processing blocks based on a difference image belonging to an adjacent block among prediction processing blocks. And (2) a second operation for dividing a block for prediction processing into a square shape and setting a block obtained by the division as a block for orthogonal transformation.

  Specifically, the orthogonal transform block size determination unit 103 uses a difference image signal in units of PUs input from the difference calculation unit 109 to perform a transform unit (a unit for performing orthogonal transform processing in the residual coefficient encoding unit 104 ( The size of a block called TU) is determined. FIG. 2 is a diagram showing selectable block sizes. As shown in FIG. 2, for example, when the CU has a block size of 64 × 64 pixels, the TU can be selected from four types of block sizes of 32 × 32 pixels to 4 × 4 pixels.

  The residual coefficient encoding unit 104 performs orthogonal transform and quantization processing for each set orthogonal transform block, and generates a residual coefficient.

  Specifically, the residual coefficient encoding unit 104 performs orthogonal transform processing on the difference image signal generated by the difference calculation unit 109 using the TU having the block size determined by the orthogonal transform block size determination unit 103 as a processing unit. . Then, the residual coefficient encoding unit 104 generates a residual coefficient signal by performing quantization processing on the obtained orthogonal transform coefficient of each frequency component.

  The residual coefficient decoding unit 105 performs inverse quantization on the residual coefficient signal input from the residual coefficient encoding unit 104 using the TU having the block size determined by the orthogonal transform block size determining unit 103 as a processing unit. Process. Further, the residual coefficient decoding unit 105 generates a reconstructed difference image signal by performing an inverse orthogonal transform process.

  The addition operation unit 110 adds the reconstructed difference image signal input from the residual coefficient decoding unit 105 and the predicted image signal input from the inter-screen prediction processing unit 107 in units of PUs, thereby adding a reconstructed image signal. Is generated.

  The picture buffer 106 stores the reconstructed image signal input from the addition operation unit 110 for reference in inter-picture prediction processing of a picture to be encoded temporally after the current encoding target picture.

  The code string generation unit 108 performs variable length encoding and arithmetic encoding on the residual coefficient signal input from the residual coefficient encoding unit 104 and an encoded information signal necessary for other decoding processes. By doing so, a code string is generated.

(Specific description of orthogonal transform block size determination unit and residual coefficient encoding unit)
Here, an orthogonal transform block size determination unit 103 and a residual coefficient encoding unit 104 determine a TU block size and perform orthogonal transform processing and quantization processing to generate a residual coefficient signal. This will be specifically described with reference to the flowchart of FIG.

  First, the orthogonal transform block size determination unit 103 receives the PU-specific difference image signal generated by the difference calculation unit 109, and totals the pixel values of the difference images of all PUs in the encoding target CU (S301). Further, the orthogonal transform block size determination unit 103 determines whether or not all pixel values are equal to or smaller than a threshold value based on the aggregation result (S302).

  FIG. 4 is a diagram illustrating an example of determination in step S301 and step S302.

  The example of FIG. 4A is a graph of the pixel values of the difference image at each pixel position in the encoding target CU. The first PU in the encoding target CU is represented by PU1, the second PU. Is PU2. Since all pixel values belonging to PU1 and PU2 are values equal to or smaller than the threshold value, it is determined that all pixel values are equal to or smaller than the threshold value as a result of the determination in step S302.

  On the other hand, in the example of FIG. 4B, since some of the pixel values belonging to PU1 and PU2 are larger than the threshold value, all pixel values are not less than or equal to the threshold value as a result of the determination in step S302. Determined.

  When it is determined in step S302 that all the pixel values are not equal to or smaller than the threshold value, in step S303, a size obtained by dividing each PU in the encoding target CU into a square shape is determined as a TU block size. On the other hand, when it is determined in step S302 that all pixel values are equal to or smaller than the threshold value, a size obtained by integrating all PUs in the encoding target CU into a square shape is determined as a TU block size in step S304.

  FIG. 5 is a diagram illustrating an example in which the TU block size is determined in steps S303 and S304. In the example of FIG. 5, there are two PUs in the encoding target CU, a 32 × 8 pixel PU and a 32 × 24 pixel PU.

  When the PU is divided in step S303, as shown in FIG. 5A, the TU block size is determined so that square TUs are spread without gaps in each PU. In FIG. 5A, a 32 × 8 pixel PU is divided into four 8 × 8 pixel TUs, and a 32 × 24 pixel PU is divided into four 8 × 8 pixel TUs and two 16 × 16 pixel TUs. It is divided into

  On the other hand, when PUs are integrated in step S304, the TU block size is determined as a square shape in which all PUs are integrated into one as shown in FIG. In FIG. 5B, a 32 × 8 pixel PU and a 32 × 24 pixel PU are integrated into one 32 × 32 pixel TU.

  Next, the residual coefficient encoding unit 104 performs orthogonal transform processing for each TU determined in step 303 or step S304 in units of TUs (S305). Then, the residual coefficient encoding unit 104 generates a residual coefficient signal by performing quantization processing on the obtained orthogonal transform coefficient of each frequency component in units of TU (S306).

  When the pixel values of all the difference images in the TU, which is a unit for performing the orthogonal transform process, have the same value, the orthogonal transform coefficients generated by the orthogonal transform process are concentrated only on the low frequency component coefficients. Therefore, information can be compressed with high efficiency by performing quantization processing.

  Originally, since the inter-screen prediction process is performed in units of PUs, motion compensation is performed from different regions for each PU to generate a predicted image, and the resulting difference image also has a different pixel structure for each PU. Therefore, it is common to perform orthogonal transform processing in units of small blocks closed in one PU. However, when the number of blocks to be subjected to orthogonal transform processing increases, information to be described in the code string is generated for each block, so that the generated code amount increases.

  However, when inter-screen prediction is performed efficiently and the pixel values of the difference images of all PUs in the encoding target can be made extremely small, even if orthogonal transform processing is performed in units of large blocks that integrate PUs Since the values are concentrated only on the low frequency component coefficients, the generated code amount can be reduced without degrading the image quality.

  In the present embodiment, orthogonal transform processing is performed in units of large blocks in which PUs are integrated only when the pixel values of the difference images of all PUs in the encoding target CU are equal to or less than a threshold value. For this reason, when the inter-screen prediction is not performed efficiently, the encoding efficiency is equivalent to the conventional one. However, when the inter-screen prediction is performed efficiently, the encoding can be performed with extremely high encoding efficiency. As a result, high image quality and a reduction in the amount of generated codes can be realized at the same time.

(Another form 1 of the orthogonal transform block size determination unit and the residual coefficient encoding unit)
Here, another method for determining the block size of the TU in the orthogonal transform block size determination unit 103 and the residual coefficient encoding unit 104, and performing orthogonal transform processing and quantization processing to generate a residual coefficient signal, This will be described with reference to the flowchart of FIG.

  Since the processing from step S301 to step S306 is exactly the same as the processing described with reference to FIG. 3, the description thereof will be omitted here, and only the processing related to the newly added step S607 will be described in detail.

  If it is determined in step S302 that all pixel values are equal to or less than the threshold value, and the size obtained by integrating all the PUs in the CU to be encoded in a square shape is determined as the TU block size in step S304, the residual coefficient encoding unit 104 Instead of performing the processing of step S305 and step S306, the processing of step S607 is performed instead.

  In step S607, the residual coefficient signals generated by the residual coefficient encoding unit 104 are all set to 0 without performing orthogonal transform processing and quantization processing on the determined TU.

  It is known that the TU to which the process of step S607 is applied has small pixel values of all the difference images in step S302. For this reason, it is possible to reduce the amount of generated codes without degrading the image quality even if the values of the residual coefficient signals are all zero. Furthermore, since it is not necessary to perform orthogonal transform processing and quantization processing, the processing amount can be reduced.

  In step S607, a process of changing all values to 0 later is performed on the residual coefficient signal generated by performing the same process as the orthogonal transform process in step S305 and the quantization process in step S306. You may go. As a result, it is possible to share the processing flow without depending on the determination result in step S302, and it is possible to achieve simplification of the processing flow although the effect of reducing the processing amount is lost.

  In the above description, the residual coefficient signals are all set to 0. However, any value may be used as long as the value can be approximated to 0.

(Another form 2 of the orthogonal transform block size determination unit and the residual coefficient encoding unit)
Here, another method for generating the residual coefficient signal by determining the block size of the TU in the orthogonal transform block size determining unit 103 and the residual coefficient encoding unit 104 and performing orthogonal transform processing and quantization processing. This will be described with reference to the flowchart of FIG.

  Since the processing from step S303 to step S306 is exactly the same as the processing described with reference to FIG. 3, the description thereof is omitted here. Only the processing relating to steps S701 and S702 newly added in place of steps S301 and S302 in FIG. 3 will be described in detail.

  The orthogonal transform block size determination unit 103 receives the difference image signal for each PU generated by the difference calculation unit 109 and extracts the maximum value and the minimum value of the pixel values of the difference images of all PUs in the encoding target CU ( S701). Further, the orthogonal transform block size determination unit 103 determines whether or not the width of the extracted maximum value and minimum value is equal to or smaller than a threshold value (S702).

  FIG. 8 is a diagram illustrating an example of determination in step S701 and step S702.

  In the example of FIG. 8A, the pixel values of the difference image at each pixel position in the encoding target CU are graphed, and the first PU in the encoding target CU is represented by PU1, the second PU. Is PU2. Since the widths of the maximum value and the minimum value of all the pixel values belonging to PU1 and PU2 are equal to or less than the threshold value, it is determined that the width of the maximum value and the minimum value is equal to or less than the threshold value as a result of the determination in step S702.

  On the other hand, in the example of FIG. 4B, since the maximum value and the minimum value width of all the pixel values belonging to PU1 and PU2 are larger than the threshold value, as a result of the determination in step S702, the maximum value and the minimum value are set. It is determined that the width is not less than the threshold value.

  If it is determined in step S702 that the width between the maximum value and the minimum value is not equal to or smaller than the threshold value, a size obtained by dividing each PU in the encoding target CU into a square shape is determined as a TU block size in step S303. On the other hand, if it is determined in step S702 that the width between the maximum value and the minimum value is equal to or smaller than the threshold value, a size obtained by integrating all PUs in the encoding target CU into a square shape is determined as a TU block size in step S304.

  When the pixel values of all the difference images in the TU, which is a unit for performing the orthogonal transform process, have the same value, the orthogonal transform coefficients generated by the orthogonal transform process are concentrated only on the low frequency component coefficients. Therefore, information can be compressed with high efficiency by performing quantization processing.

  Comparing the example of FIG. 4A and the example of FIG. 8A, each pixel value has a larger value in the example of FIG. 8A. However, when variations are compared, the example shown in FIG. 8A is as small as FIG. 4A, and the orthogonal transform coefficients generated by the orthogonal transform process are concentrated only in the low-frequency component coefficients. To do. For this reason, even if orthogonal transform processing is performed in units of large blocks in which PUs are integrated, the amount of generated codes can be reduced without degrading image quality.

(Another form 3 of the orthogonal transform block size determination unit and the residual coefficient encoding unit)
Here, another method for generating the residual coefficient signal by determining the block size of the TU in the orthogonal transform block size determining unit 103 and the residual coefficient encoding unit 104 and performing orthogonal transform processing and quantization processing. This will be described with reference to the flowchart of FIG.

  Since the processing from step S303 to step S306 is exactly the same as the processing described with reference to FIG. 3, the description thereof is omitted here. Only the processing relating to steps S901 and S902 newly added in place of steps S301 and S302 in FIG. 3 will be described in detail.

  The orthogonal transform block size determination unit 103 receives a difference image signal in units of PUs generated by the difference calculation unit 109 as an input, and a boundary difference value that is a difference between pixel values of a difference image between the PU and the PU in the encoding target CU. Is extracted (S901). Further, the orthogonal transform block size determination unit 103 determines whether or not the extracted total boundary difference value is equal to or smaller than a threshold value (S902).

  FIG. 10 is a diagram illustrating an example of determination in step S901 and step S902.

  The example of FIG. 10A is a graph of the pixel value of the difference image at each pixel position in the encoding target CU. The first PU in the encoding target CU is represented by PU1, the second PU. Is PU2. It shows that the difference between pixel values adjacent to the boundary between PU1 and PU2 (boundary difference value) is less than or equal to the threshold value. In the example of FIG. 10A, the pixel position is represented by a one-dimensional graph. Therefore, although there is only one boundary difference value, the difference image to be processed is originally a two-dimensional image. Therefore, there are boundary difference values as many as the number of pixel pairs adjacent to the boundary between PU and PU. If all the boundary difference values are similarly equal to or less than the threshold value, it is determined that all the boundary difference values are equal to or less than the threshold value as a result of the determination in step S902.

  On the other hand, in the example of FIG. 10B, since the difference (boundary difference value) between the pixel values adjacent to the boundary between PU1 and PU2 is larger than the threshold value, as a result of the determination in step S902, the entire boundary difference value is the threshold value. It is determined that it is not below.

  If it is determined in step S902 that the total boundary difference value is not equal to or smaller than the threshold value, the size obtained by dividing each PU in the encoding target CU into a square shape is determined as a TU block size in step S303. On the other hand, if it is determined in step S902 that the total boundary difference value is equal to or smaller than the threshold value, a size obtained by integrating all PUs in the encoding target CU into a square shape is determined as a TU block size in step S304.

  When the pixel values of all the difference images in the TU, which is a unit for performing the orthogonal transform process, have the same value, the orthogonal transform coefficients generated by the orthogonal transform process are concentrated only on the low frequency component coefficients. Therefore, information can be compressed with high efficiency by performing quantization processing.

  If the difference between the pixel values adjacent to the boundary between PU1 and PU2 is a large value as in the example of FIG. 10B, when orthogonal transformation processing is performed in units of large blocks in which PU1 and PU2 are integrated, Information is also dispersed in the coefficient of the high frequency component of the conversion coefficient. For this reason, many residual coefficients are generated even if the quantization process is performed, and information cannot be compressed with high efficiency.

  On the other hand, as in the example of FIG. 10A, when the difference between the pixel values adjacent to the boundary between PU1 and PU2 is small, even when orthogonal transformation processing is performed in units of large blocks in which PU1 and PU2 are integrated. Therefore, the possibility that information is dispersed in the coefficient of the high frequency component of the orthogonal transform coefficient is reduced. Therefore, the generated code amount can be reduced without degrading the image quality.

(Summary)
A moving image encoding apparatus 100 according to the present embodiment is a moving image encoding apparatus that generates a code string by encoding an encoding target picture according to a predetermined encoding standard including inter-screen prediction processing. A block dividing unit 102 for outputting a pixel constituting a picture to be processed for each output block having any one of a plurality of block sizes set in advance, and pixels belonging to the output block, A prediction processing block having a block size equal to or smaller than the output block size is set, and an inter-screen prediction processing unit 107 that generates a prediction image for each prediction processing block, and is generated for each prediction processing block. The prediction image and the pixels belonging to the output block corresponding to each of the prediction images are subjected to a difference calculation, and a difference image is generated in units of prediction processing blocks. Based on the difference calculation unit 109 and a difference image belonging to an adjacent block among the prediction processing blocks, (1) a square block obtained by integrating adjacent prediction processing blocks is used as an orthogonal transform block. An orthogonal transform block size determination unit that executes a first operation to be set and (2) a second operation to divide a block for prediction processing into a square shape and set a block obtained by the division as a block for orthogonal transform 103 and a residual coefficient encoding unit 104 that performs orthogonal transform and quantization processing for each set orthogonal transform block and generates a residual coefficient.

  Also, the orthogonal transform block size determination unit 103 in the present embodiment integrates the adjacent prediction processing blocks when the prediction processing blocks whose pixel values of all the difference images belong to the predetermined threshold value are adjacent to each other. It is generated as a square-shaped orthogonal transform block.

  In addition, when the orthogonal transform block size determining unit 103 integrates adjacent prediction processing blocks and generates a square-shaped orthogonal transform block, the residual coefficient encoding unit 104 according to the present embodiment performs orthogonality after integration. All residual coefficients belonging to the block for conversion are generated as 0.

  In the present embodiment, the orthogonal transform block size determination unit 103, when the blocks for prediction processing in which the width of the minimum value and the maximum value of the difference image to which the difference image belongs are values within a predetermined range are adjacent to each other, The processing blocks are integrated to generate a square orthogonal transform block.

The orthogonal transform block size determination unit 103 according to the present embodiment, when the difference between the pixel values sandwiching the adjacent boundary among the pixel values of the difference image belonging to the adjacent prediction processing block is equal to or less than a predetermined threshold, The processing blocks are integrated to generate a square orthogonal transform block.
(Other embodiments)
Further, the program having the same function as each unit included in the moving picture encoding apparatus shown in the above embodiment is recorded on a recording medium such as a flexible disk, thereby showing the above embodiment. Processing can be easily performed in an independent computer system. The recording medium is not limited to a flexible disk, and can be similarly implemented as long as it can record a program, such as an optical disk, an IC card, and a ROM cassette.

  In addition, a function equivalent to each unit included in the moving picture coding apparatus described in the above embodiment may be realized as an LSI which is an integrated circuit. These may be integrated into one chip so as to include a part or all of them. An LSI may also be called an IC, a system LSI, a super LSI, or an ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Furthermore, if integrated circuit technology that replaces LSI or the like appears as a result of progress in semiconductor technology or other derived technology, it is naturally also possible to carry out function block integration using this technology.

  Moreover, you may combine at least one part among the functions of the moving image encoder which concerns on the said embodiment, or its modification.

  INDUSTRIAL APPLICABILITY The present invention is useful as a moving image encoding apparatus that encodes each picture constituting an input image and outputs it as moving image encoded data in, for example, a video camera, a digital camera, a video recorder, a mobile phone, and a personal computer. It is.

DESCRIPTION OF SYMBOLS 100 Moving image encoding apparatus 101 Picture memory 102 Block division part 103 Orthogonal transformation block size determination part 104 Residual coefficient encoding part 105 Residual coefficient decoding part 106 Picture buffer 107 Inter-screen prediction process part 108 Code stream generation part 109 Difference Calculation unit 110 Addition calculation unit

Claims (6)

A video encoding device that encodes a picture to be encoded with a predetermined encoding standard including inter-screen prediction processing and generates a code string,
A block dividing unit that outputs pixels constituting the encoding target picture for each output block having any one of a plurality of block sizes set in advance;
Inter-screen prediction processing for setting a prediction processing block having a block size equal to or smaller than the output block size for pixels belonging to the output block and generating a prediction image for each block for the prediction processing And
The difference calculation is performed between the prediction image generated for each block for prediction processing and the pixels belonging to the output block corresponding to each of the prediction images, and a difference image is generated in units of blocks for the prediction processing. A difference calculation unit;
Based on the difference image belonging to an adjacent block among the prediction processing blocks, (1) a square block obtained by integrating the adjacent prediction processing blocks is set as a block for orthogonal transformation. (2) an orthogonal transform block size determining unit that executes a second operation of dividing the block for prediction processing into a square shape and setting the block obtained by the division as a block for orthogonal transform;
For each of the set orthogonal transform blocks, a residual coefficient encoding unit that performs orthogonal transform and quantization processing to generate a residual coefficient, and
Video encoding device.   The orthogonal transform block size determination unit integrates the adjacent prediction processing blocks when the pixel values of all the difference images to which the pixel values are equal to or less than a predetermined threshold are adjacent to each other, and forms a square orthogonal transform. The moving picture coding apparatus according to claim 1, wherein the moving picture coding apparatus is generated as a block for use.   In the orthogonal transform block size determination unit, the residual coefficient encoding unit integrates adjacent prediction processing blocks and generates a square orthogonal transform block. The moving picture encoding apparatus according to claim 2, wherein all the residual coefficients belonging thereto are generated as zero.   The orthogonal transform block size determination unit, when a block for prediction processing in which the width of the minimum value and the maximum value of the difference image to which the image belongs belongs is a value within a predetermined range is adjacent to the block for prediction processing The moving picture coding apparatus according to claim 1, wherein the blocks are integrated and generated as a square-shaped orthogonal transform block.   The orthogonal transform block size determination unit, when the difference between the pixel values sandwiching the adjacent boundary among the pixel values of the difference image belonging to the adjacent prediction processing block is equal to or smaller than a predetermined threshold, the adjacent prediction processing block The moving picture coding apparatus according to claim 1, wherein the blocks are integrated and generated as a square-shaped orthogonal transform block. A video encoding method for encoding a picture to be encoded with a predetermined encoding standard including inter-screen prediction processing and generating a code string,
Output pixels constituting the encoding target picture for each output block having any one of a plurality of preset block sizes,
For a pixel belonging to the output block, set a block for prediction processing having a block size equal to or smaller than the block size for output, and generate a prediction image for each block for prediction processing,
The difference calculation is performed between the prediction image generated for each block for prediction processing and the pixel belonging to the output block corresponding to each prediction image, and a difference image is generated in units of the block for prediction processing. ,
Based on the difference image belonging to an adjacent block among the prediction processing blocks, (1) a square block obtained by integrating the adjacent prediction processing blocks is set as a block for orthogonal transformation. And (2) performing a second operation of dividing the block for prediction processing into a square shape and setting a block obtained by the division as a block for orthogonal transformation,
For each of the set orthogonal transform blocks, orthogonal transform and quantization processing are performed to generate a residual coefficient.
Video encoding method.