WO2011033643A1 - Dynamic image encoding method and dynamic image decoding method - Google Patents

Dynamic image encoding method and dynamic image decoding method Download PDF

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Publication number
WO2011033643A1
WO2011033643A1 PCT/JP2009/066303 JP2009066303W WO2011033643A1 WO 2011033643 A1 WO2011033643 A1 WO 2011033643A1 JP 2009066303 W JP2009066303 W JP 2009066303W WO 2011033643 A1 WO2011033643 A1 WO 2011033643A1
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Prior art keywords
filter
information
block
unit
decoding
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PCT/JP2009/066303
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French (fr)
Japanese (ja)
Inventor
豪毅 安田
中條　健
昭行 谷沢
隆志 渡辺
直史 和田
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株式会社 東芝
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Priority to CN2009801611724A priority Critical patent/CN102484713A/en
Priority to PCT/JP2009/066303 priority patent/WO2011033643A1/en
Priority to JP2011531717A priority patent/JPWO2011033643A1/en
Publication of WO2011033643A1 publication Critical patent/WO2011033643A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/80—Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation
    • H04N19/82—Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation involving filtering within a prediction loop
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • 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
    • H04N19/109—Selection of coding mode or of prediction mode among a plurality of temporal predictive coding modes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • 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
    • H04N19/117—Filters, e.g. for pre-processing or post-processing
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • 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
    • H04N19/119—Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/46—Embedding additional information in the video signal during the compression process
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding

Definitions

  • the present invention relates to encoding and decoding of moving images.
  • H. is one of the international standards for video coding.
  • H.264 / MPEG-4AVC (hereinafter simply referred to as H.264) was jointly established by ITU-T (International Telecommunication Union Telecommunication Standardization Sector) and ISO / IEC (International Organization for Standardization / International Electrotechnical Commission) .
  • H. H.264 achieves a high compression efficiency of more than twice that of MPEG-2.
  • H.H. H.264 a reference image related to an encoded image or a decoded image is used to generate a predicted image.
  • a loop filter process may be performed on the local decoded image or the decoded image.
  • a deblocking filter as disclosed in Non-Patent Document 1 is used in the loop filter processing.
  • the deblocking filter reduces visually noticeable image quality degradation (so-called block distortion) by blurring the local decoded image or the block boundary of the decoded image.
  • block distortion visually noticeable image quality degradation
  • H.H. H.264 employs a mechanism that adaptively changes the filter strength of the deblocking filter in accordance with conditions such as the prediction mode of the processing target block and the size of the pixel difference value near the block boundary.
  • a plurality of inter-pixel filters are prepared in advance, and for example, a loop filter process is selectively performed for each picture. Then, the information on the selected inter-pixel filter is transmitted to the decoding side, thereby realizing a common loop filter process between encoding / decoding.
  • the filter selection unit is set to be small (for example, set to a pixel block) in order to improve image quality, the overhead code amount of the filter selection information increases. That is, in the image encoding method described in Patent Document 1, if a large number of filters are prepared or the filter selection unit is set small, the encoding efficiency is lowered.
  • an object of the present invention is to provide moving image encoding / moving image decoding capable of encoding parameters relating to loop filter processing with high efficiency.
  • a moving image encoding method is a moving image encoding method for generating a predicted image using a reference image related to an encoded image, wherein a local decoded image of a coding unit is divided into a plurality of blocks.
  • Setting block division information including parameters for dividing, setting filter information including filter coefficients of each filter of the filter group for the coding unit, and the number of filters included in the filter group
  • Setting filter number information indicating, setting filter specifying information for specifying a filter to be applied to each block, applying a filter specified by the filter specifying information for each block, and Generating an image; and the filter number information, the filter information, the block division information, and the filter specifying information.
  • Comprising a to-coding including parameters for dividing, setting filter information including filter coefficients of each filter of the filter group for the coding unit, and the number of filters included in the filter group
  • Setting filter number information indicating, setting filter specifying information for specifying a filter to be applied to each block, applying a filter specified by the filter
  • a moving picture decoding method is a moving picture decoding method for generating a predicted picture using a reference picture related to a decoded picture, wherein a decoded picture of a decoding unit is divided into a plurality of blocks.
  • Decoding block division information including parameters for division, decoding filter number information indicating the number of filters included in the filter group for the decoding unit, and each filter of the filter group Decoding the filter information including the filter coefficients, decoding the filter specifying information for specifying the filter to be applied to each block, and applying the filter specified by the filter specifying information for each block And generating the reference image.
  • FIG. 1 is a block diagram showing a moving image encoding apparatus according to a first embodiment.
  • 3 is a block diagram showing a loop filter processing unit 300.
  • movement of the moving image encoder of FIG. The block diagram which shows the moving image decoding apparatus which concerns on 1st Embodiment.
  • FIG. 5 is a flowchart showing the operation of the video decoding device in FIG. 4.
  • movement of the moving image encoder of FIG. The flowchart which shows operation
  • FIG. 11 is a flowchart showing the operation of the video decoding device in FIG. 10.
  • 11 is a flowchart showing the operation of the video decoding device in FIG. 10.
  • FIG. 5 is a diagram showing an example of filter application of a reference image signal according to the first embodiment.
  • the moving picture coding apparatus includes a moving picture coding unit 1000 and a coding control unit 108.
  • the moving image encoding unit 1000 includes a prediction signal generation unit 101, a subtractor 102, a transform / quantization unit 103, an entropy encoding unit 104, an inverse transform / inverse quantization unit 105, an adder 106, a reference image buffer 107, and a loop.
  • a filter processing unit 300 is included.
  • the prediction signal generation unit 101 performs a predetermined prediction process based on the reference image signal 17 related to the encoded image stored in the reference image buffer 107.
  • the prediction signal generation unit 101 generates a prediction image signal 11 of the input image signal 10 by prediction processing, and inputs the prediction image signal 11 to the subtracter 102 and the adder 106.
  • the prediction process may be an inter prediction method that realizes temporal prediction by using motion prediction and motion compensation, or an intra prediction method that realizes spatial prediction by using surrounding pixel values. It may be.
  • the subtracter 102 subtracts the prediction image signal 11 from the prediction signal generation unit 101 from the input image signal 10 to obtain a prediction error signal 12.
  • the subtractor 102 inputs the prediction error signal 12 to the transform / quantization unit 103.
  • the transform / quantization unit 103 orthogonally transforms the prediction error signal 12 from the subtractor 102 to obtain an orthogonal transform coefficient.
  • the transform / quantization unit 103 of this embodiment uses, for example, DCT (Discrete Cosine Transform) as orthogonal transform.
  • the transform / quantization unit 103 quantizes the orthogonal transform coefficient according to the quantization parameter to obtain a quantized orthogonal transform coefficient (hereinafter simply referred to as a quantized transform coefficient) 13.
  • the quantization parameter is controlled by the encoding control unit 108.
  • the transform / quantization unit 103 inputs the quantized transform coefficient 13 to the entropy coding unit 104 and the inverse transform / inverse quantization unit 105.
  • the entropy encoding unit 104 encodes the quantized transform coefficient 13 from the transform / quantization unit 103, the filter number information 31 from the loop filter processing unit 300, the filter information 32, the block division information 33, and the filter identification information 34. Get as. Further, the entropy encoding unit 104 may acquire a prediction mode, a motion vector, a quantization parameter, and the like as encoding parameters. The entropy encoding unit 104 performs entropy encoding (Huffman encoding or arithmetic encoding) on the multiplexed encoding parameter, generates encoded data 14, and outputs the encoded data 14 to the outside.
  • entropy encoding Huffman encoding or arithmetic encoding
  • the inverse transform / inverse quantization unit 105 inversely quantizes the quantized transform coefficient 13 according to the quantization parameter to restore the orthogonal transform coefficient.
  • the quantization parameter is the same as that of the transform / quantization unit 103.
  • the inverse transform / inverse quantization unit 105 performs inverse orthogonal transform such as IDCT (Inverse DCT) on the orthogonal transform coefficient to restore the prediction error signal 12.
  • IDCT Inverse DCT
  • the inverse orthogonal transform corresponds to the orthogonal transform performed in the transform / quantization unit 103.
  • the inverse transform / inverse quantization unit 105 inputs the restored prediction error signal 12 as the prediction error signal 15 to the adder 106.
  • the adder 106 adds the prediction error signal 15 from the inverse transform / inverse quantization unit 105 and the prediction image signal 11 from the prediction signal generation unit 101 to restore the input image signal 10.
  • the adder 106 inputs the restored input image signal 10 as the local decoded image signal 16 to the loop filter processing unit 300.
  • the reference image buffer 107 temporarily stores the reference image signal 17 from the loop filter processing unit 300.
  • the reference image signal 17 is appropriately read by the prediction signal generation unit 101.
  • the encoding control unit 108 performs overall control of each component of the moving image encoding unit 1000. For example, the encoding control unit 108 instructs the loop filter processing unit 300 with the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34. Also, the encoding control unit 108 performs feedback control of generated code amount, quantization control, mode control, and the like.
  • the loop filter processing unit 300 includes a block dividing unit 301, a filter switching unit 302, a filter processing unit 303, and a block integration unit 304.
  • the loop filter processing unit 300 performs a loop filter process on the local decoded image signal 16 in a coding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 300 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, and the filter identification information 34 from the encoding control unit 108.
  • the number-of-filters information 31, the filter information 32, the block division information 33, and the filter specifying information 34 from the encoding control unit 108 are also input to the entropy encoding unit 104.
  • the loop filter processing unit 300 may process an image signal obtained by performing a deblocking filter process on the local decoded image signal 16 in a coding unit.
  • the block division unit 301 divides the local decoded image signal 16 into a plurality of local decoded pixel blocks 35 having a predetermined size according to the block division information 33.
  • the block division information 33 is set for each coding unit.
  • the block division information 33 indicates a division parameter for dividing the local decoded image signal 16 of a coding unit into a plurality of local decoded pixel blocks 35 having a predetermined size.
  • the division parameter is a parameter indicating the predetermined size or the division mode, for example.
  • the block dividing unit 301 inputs the locally decoded pixel block 35 to the filter switching unit 302.
  • the filter switching unit 302 switches the filter for the local decoded pixel block 35 in accordance with the filter specifying information 34.
  • the filter specifying information 34 is set for each local decoded pixel block 35.
  • the filter specifying information 34 specifies a filter selected for the local decoded pixel block 35.
  • the filter switching unit 302 includes a switch SW that switches the output destination of the local decoded pixel block 35 among terminals s1,..., Sn (n is a natural number).
  • the filter processing unit 303 prepares a filter group for each coding unit based on the filter number information 31 and the filter information 32.
  • the filter group includes at least one filter.
  • the filter number information 31 indicates the number of filters included in the filter group.
  • the filter information 32 indicates the filter coefficient of each filter.
  • the filter number information 31 and the filter information 32 are set for each coding unit. That is, the filter processing unit 303 prepares n filters F1,... Fn based on the filter information 32 for each encoding unit. As shown in FIG. 2 (path including the terminal sn), the filter processing unit 303 may prepare an unprocessed (bypass) filter.
  • the filter processing unit 303 applies the filter selected by the filter switching unit 302 to the local decoded pixel block 35 to generate a filtered pixel block 36.
  • the filter prepared by the filter processing unit 303 is an image restoration filter (for example, a two-dimensional Wiener filter), and the filtered pixel block 36 is simply referred to as a restoration pixel block 36.
  • the filter processing unit 303 inputs the restored pixel block 36 to the block integration unit 304.
  • the block integration unit 304 integrates the restored pixel block 36 from the filter processing unit 303 and obtains a reference image signal 17 of a coding unit.
  • the block integration unit 304 inputs the reference image signal 17 of the coding unit to the reference image buffer 107.
  • the encoding control unit 109 sets the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 (step S1100).
  • the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 may be set manually by the user or automatically according to a predetermined algorithm.
  • the filter number information 31 indicates the number n of filters prepared in each coding unit, and an integer value of 1 or more is set.
  • the filter specifying information 34 is selection information regarding n filters. For example, in order to select the filters F1,..., Fn, integer values of 1,.
  • the filter information 32 includes filter coefficients of the filters F1,.
  • the filters F1,... Fn may be two-dimensional Wiener filters. Wiener filter is generally used in image restoration. A filter coefficient for minimizing the mean square error between the reference image signal 17 and the input image signal 10 is set in Wiener filter. By using the Wiener filter, it is possible to effectively improve the image quality while reducing the number of selection candidates, compared to the case where a large number of fixed filters are prepared as selection candidates between the encoding side and the decoding side. . By reducing the number of selection candidates, the overhead code amount of the filter specifying information 34 is suppressed.
  • Filter parameters other than filter coefficients may be defined in advance between the encoding side and the decoding side. However, it may be included in the filter information 32.
  • the filter parameter may be directly expressed by a parameter value or may be expressed by an index.
  • the filter parameter is expressed by an index, a common table in which the index is associated with the parameter value needs to be created in advance between the encoding side and the decoding side.
  • the encoding side can control the image quality improvement performance, the code amount of the filter information 32, the calculation amount of the filter processing, and the like. Also, it is possible to improve the coding efficiency by appropriately controlling the filter parameters in units of sequences, frames, and the like.
  • the block division information 33 indicates a division parameter for dividing the local decoded image signal 16 of a coding unit into a plurality of local decoded pixel blocks 35 having a predetermined size. For example, if the local decoded pixel block 35 is square, the block division information 33 may be the number of pixels on one side of the local decoded pixel block 35. Further, the block division information 33 may be an index indicating the shape, size, division mode, and the like of the locally decoded pixel block 35. When the block division information 33 is expressed by an index, a common table in which the index is associated with the shape, size, division mode, and the like of the local decoded pixel block 35 is created in advance between the encoding side and the decoding side. It is necessary to keep.
  • the loop filter processing unit 300 acquires the filter number information 31 and the filter information 32 set in step S1100 (step S1101).
  • the filter processing unit 303 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S1101 (step S1102).
  • the loop filter processing unit 300 acquires the block division information 33 set in step S1100 (step S1103).
  • the block division unit 301 divides the local decoded image signal 16 of the coding unit into a plurality of local decoded pixel blocks 35 according to the block division information 33 acquired in step S1103 (step S1104).
  • the loop filter processing unit 300 initializes a counter variable i for counting the processed local decoded pixel block 35 (step S1105), and the process proceeds to step S1106. Note that the processing of step S1106 to step S1109 is performed in units of local decoded pixel blocks 35.
  • step S1106 the filter switching unit 302 acquires the filter specifying information 34 corresponding to the (i-th) local decoded pixel block 35 to be processed.
  • the filter switching unit 302 switches the connection of the switch SW so that the local decoded pixel block 35 to be processed is supplied to one of the filters F1,..., Fn according to the filter specifying information 34 acquired in step S1106 ( Step S1107).
  • the filter processing unit 303 acquires the local decoded pixel block 35 to be processed from the filter switching unit 302 (step S1108).
  • the filter processing unit 303 applies one of the filters F1,..., Fn to the local decoded pixel block 35 acquired in step S1108 according to the connection of the switch SW in step S1107, and generates the restored pixel block 36 ( In step S1109), the process proceeds to step S1110.
  • step S1110 the loop filter processing unit 300 compares the constant NumOfBlock indicating the total number of locally decoded pixel blocks 35 in the coding unit with the value of the counter variable i. If the value of counter variable i is less than the constant NumOfBlock, the process proceeds to step S1111; otherwise, the process proceeds to step S1112. In step S1111, the loop filter processing unit 300 increments the counter variable i by 1, and the process returns to step S1106.
  • the entropy encoding unit 104 entropy encodes the encoding parameters including the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 set in step S1100 (step S1113), and the process ends.
  • the filter number information 31, the filter information 32, and the block division information 33 are set in units of slices, and the filter specifying information 34 is set in units of pixel blocks.
  • High-level syntax 1900 describes parameters of higher layers above the slice.
  • the slice level syntax 1903 describes parameters for each slice.
  • the macro block level syntax 1907 describes parameters (quantized transform coefficient 13, prediction mode, motion vector, etc.) for each macro block.
  • the high level syntax 1900 includes a sequence parameter set syntax 1901 and a picture parameter set syntax 1902.
  • the sequence parameter set syntax 1901 describes parameters for each sequence.
  • the picture parameter set syntax 1902 describes parameters for each picture.
  • the slice level syntax 1903 includes a slice header syntax 1904, a slice data syntax 1905, and a loop filter data syntax 1906.
  • the macroblock level syntax 1907 includes a macroblock layer syntax 1908 and a macroblock prediction syntax 1909.
  • loop filter data syntax 1907 Parameters relating to loop filter processing according to the present embodiment are described in the loop filter data syntax 1907 in FIG. That is, in the loop filter data syntax 1907, as shown in FIG. 16, filter number information 31, filter information 32, block division information 33, and filter specifying information 34 are described.
  • num_of_filter represents the filter number information 31.
  • filter_coeff [idx] [cy] [cx] is a filter coefficient (that is, at least a part of the filter information 32) at the position of the cy-th row and the cx-th column of the idx-th filter in the filter group.
  • the filter coefficient represents the filter coefficient value itself or difference information as a result of the prediction of the filter coefficient.
  • the filter sizes filter_size_x and filter_size_y are predetermined between the encoding side and the decoding side, but may be set by the filter parameter included in the filter information 32. Good.
  • filter_block_size represents block division information 33.
  • filter_idx [i] represents the filter specifying information 34 corresponding to the i-th pixel block.
  • the filter_idx [i] is encoded by commonly used Huffman encoding, arithmetic encoding, or the like.
  • filter_idx [i] may be encoded according to a predetermined variable length table. Note that the variable length table may be switched at a predetermined timing so that a short code is assigned to filter_idx having a high appearance frequency.
  • filter parameters other than the filter coefficient may be further described in the syntax of FIG. Good.
  • the moving picture decoding apparatus includes a moving picture decoding unit 2000 and a decoding control unit 206.
  • the moving picture decoding unit 2000 includes an entropy decoding unit 201, an inverse transform / inverse quantization unit 202, an adder 203, a reference image buffer 204, a prediction signal generation unit 205, and a loop filter processing unit 400.
  • the entropy decoding unit 201 performs entropy decoding on the code string of the encoded data 14 according to the syntax structure of FIG. From the decoded code string, the entropy decoding unit 201 performs quantization transform coefficient 13, filter number information 31, filter information 32, block division information 33, filter identification information 34, prediction mode, motion vector, quantization parameter, and the like. Are demultiplexed. Specifically, the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 according to the syntax of FIG. The entropy decoding unit 201 inputs the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 to the loop filter processing unit 400.
  • the inverse transform / inverse quantization unit 202 dequantizes the quantized transform coefficient 13 from the entropy decoding unit 201 according to the quantization parameter, and restores the orthogonal transform coefficient.
  • the quantization parameter is decoded by the entropy decoding unit 201.
  • the inverse transform / inverse quantization unit 202 performs inverse orthogonal transform on the orthogonal transform coefficient to obtain the prediction error signal 15.
  • the inverse transform / inverse quantization unit 202 inputs the prediction error signal 15 to the adder 203.
  • the adder 203 adds the prediction image signal 11 from the prediction signal generation unit 205 and the prediction error signal 15 from the inverse transform / inverse quantization unit 202 to generate a decoded image signal 21.
  • the reference image buffer 204 temporarily stores the reference image signal 17 from the loop filter processing unit 400. The reference image signal 17 is appropriately read out by the prediction signal generation unit 205.
  • the prediction signal generation unit 205 performs prediction processing (intra prediction processing, inter prediction processing, etc.) according to a prediction mode, a motion vector, and the like based on the reference image signal 17 related to the decoded image stored in the reference image buffer 204. To generate the predicted image signal 11.
  • the prediction mode and the motion vector are decoded by the entropy decoding unit 201.
  • the predicted signal generation unit 205 inputs the predicted image signal 11 to the adder 203.
  • the decoding control unit 206 performs overall control of each component of the moving image decoding unit 2000. For example, the decoding control unit 206 controls the decoding timing.
  • the loop filter processing unit 400 includes a block dividing unit 401, a filter switching unit 402, a filter processing unit 403, and a block integration unit 404.
  • the loop filter processing unit 400 performs a loop filter process on the decoded image signal 21 of a decoding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 400 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 from the entropy decoding unit 201.
  • the loop filter processing unit 400 may process an image signal obtained by performing a deblocking filter process on the decoded image signal 21 of a decoding unit.
  • the block division unit 401 divides the decoded image signal 21 into a plurality of decoded pixel blocks 41 having a predetermined size according to the block division information 33.
  • the block division information 33 is set for each decoding unit.
  • the block division information 33 indicates a division parameter (for example, the predetermined size, the division mode, etc.) for dividing the decoded image signal 21 of a decoding unit into a plurality of decoded pixel blocks 41 having a predetermined size.
  • the block division unit 401 inputs the decoded pixel block 41 to the filter switching unit 402.
  • the filter switching unit 402 switches the filter for the decoded pixel block 41 in accordance with the filter specifying information 34.
  • the filter specifying information 34 is set for each decoded pixel block 41.
  • the filter specifying information 34 specifies a filter selected for the decoded pixel block 41.
  • the filter switching unit 402 includes a switch SW that switches the output destination of the decoded pixel block 41 between the terminals s1, ..., sn.
  • the filter processing unit 403 prepares a filter group for each decoding unit based on the filter number information 31 and the filter information 32.
  • the filter group includes at least one filter.
  • the filter number information 31 indicates the number of filters included in the filter group.
  • the filter information 32 indicates the filter coefficient of each filter.
  • the filter number information 31 and the filter information 32 are set for each decoding unit. That is, the filter processing unit 403 prepares n filters F1,... Fn based on the filter information 32 for each decoding unit. As shown in FIG. 5 (path including the terminal sn), the filter processing unit 403 may prepare an unprocessed (bypass) filter.
  • the filter processing unit 403 applies the filter selected by the filter switching unit 402 to the decoded pixel block 41 to generate the restored pixel block 36.
  • the filter processing unit 403 inputs the restored pixel block 36 to the block integration unit 404.
  • the block integration unit 404 integrates the restored pixel block 36 from the filter processing unit 403 and obtains a reference image signal 17 of a decoding unit.
  • the block integration unit 404 inputs the reference image signal 17 of the decoding unit to the reference image buffer 204.
  • the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 (step S2100).
  • the loop filter processing unit 400 acquires the filter number information 31 and the filter information 32 set in step S2100 (step S2101).
  • the filter processing unit 403 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S2101 (step S2102).
  • the loop filter processing unit 400 acquires the block division information 33 set in step S2100 (step S2103).
  • the block division unit 401 divides the decoded image signal 21 of the decoding unit into a plurality of decoded pixel blocks 41 according to the block division information 33 acquired in step S2103 (step S2104).
  • the loop filter processing unit 400 initializes a counter variable i for counting the processed decoded pixel block 41 (step S2105), and the process proceeds to step S2106. Note that the processing from step S2106 to step S2109 is performed for each decoded pixel block 41.
  • step S2106 the filter switching unit 402 acquires the filter specifying information 34 corresponding to the (i-th) decoded pixel block 41 to be processed.
  • the filter switching unit 402 switches the connection of the switch SW so that the decoding pixel block 41 to be processed is supplied to one of the filters F1,..., Fn according to the filter specifying information 34 acquired in Step S2106 (Step S2106). S2107).
  • the filter processing unit 403 acquires the decoded pixel block 41 to be processed from the filter switching unit 402 (step S2108).
  • the filter processing unit 403 applies one of the filters F1,..., Fn to the decoded pixel block 41 acquired in step S2108 according to the connection of the switch SW in step S2107, and generates the restored pixel block 36 (step S2109). ), The process proceeds to step S2110.
  • step S2110 the loop filter processing unit 400 compares the constant NumOfBlock indicating the total number of decoded pixel blocks 41 in the decoding unit with the value of the counter variable i. If the value of counter variable i is less than the constant NumOfBlock, the process proceeds to step S2111; otherwise, the process proceeds to step S2112. In step S2111, the loop filter processing unit 400 increments the counter variable i by 1, and the process returns to step S2106.
  • the number of filters prepared in the encoding / decoding unit, the filter selection unit, and the like are arbitrarily set on the encoding side. Yes. Therefore, according to the moving image encoding / moving image decoding according to the present embodiment, the overhead code amount related to the loop filter processing is controlled according to the required bit rate and the like, and the parameters related to the loop filter processing are encoded with high efficiency.
  • the code amount of the filter information 32 can be controlled by increasing or decreasing the number of filters indicated by the filter number information 31.
  • the code amount of the filter specifying information 34 can be controlled by changing the division parameter indicated by the block division information 33.
  • the moving picture coding apparatus according to the second embodiment of the present invention corresponds to a configuration in which the loop filter processing unit 300 in the moving picture coding apparatus of FIG. To do.
  • the same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be mainly described.
  • the entropy encoding unit 104 includes the quantized transform coefficient 13 from the transform / quantization unit 103, the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information from the loop filter processing unit 300. 51 is acquired as an encoding parameter. Further, the entropy encoding unit 104 may acquire a prediction mode, a motion vector, a quantization parameter, and the like as encoding parameters. The entropy encoding unit 104 performs entropy encoding on the multiplexed encoding parameter, generates encoded data 14 and outputs the encoded data 14 to the outside.
  • the loop filter processing unit 500 includes a block dividing unit 301, a filter switching unit 302, a filter application switching unit 510, a filter processing unit 503, and a block integration unit 304.
  • the loop filter processing unit 500 performs a loop filter process on the local decoded image signal 16 in a coding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 500 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 from the encoding control unit 108. .
  • the filter number information 31, the filter information 32, the block division information 33, the filter identification information 34, and the filter application information 51 from the encoding control unit 108 are also input to the entropy encoding unit 104.
  • the loop filter processing unit 500 may process an image signal obtained by performing a deblocking filter process on the local decoded image signal 16 in a coding unit.
  • the filter application switching unit 510 switches application / non-application of the filter for each sub-block obtained by further dividing the local decoded pixel block 35 (hereinafter also referred to as a main block for convenience) according to the filter application information 51.
  • the filter application information 51 is set for each sub-block.
  • the filter application information 51 specifies application / non-application of the filter selected for the main block according to the filter specifying information 34 for each sub-block.
  • the filter application switching unit 510 is a total of the switches SWn for switching the output destination of each sub-block between the terminal t1 and the terminal u1, and the switch SWn for switching between the terminal tn and the terminal un. Includes n switches.
  • the division parameter for dividing the main block into sub-blocks may be controlled by the block division information 33 or other information, or may be determined in advance on the encoding side and decoding side.
  • the division parameter may be a sub-block size or a division mode (such as quadtree division).
  • the filter processing unit 503 prepares a filter group including the number of filters specified by the filter number information 31 based on the filter information 32, similarly to the filter processing unit 303. That is, the filter processing unit 503 prepares n filters F1,... Fn based on the filter information 32 for each encoding unit. Each filter F1,..., Fn is connected to a terminal t1,. In addition, an unprocessed (bypass) path is connected to the terminals u1,..., Un corresponding to the non-application of the filters F1,. The filter processing unit 503 processes the filters F1,..., Fn on the sub-blocks input from the terminals t1,. The filter processing unit 503 outputs the sub-blocks input from the terminals u1,.
  • the encoding control unit 109 sets the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 (step S3100).
  • the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 may be set manually by the user or automatically according to a predetermined algorithm.
  • the filter application information 51 is a parameter that specifies application / non-application of the filter selected for the main block in accordance with the filter identification information 34 in units of sub-blocks.
  • the value of the filter application information 51 is, for example, 1 when indicating application of a filter, and 0 when indicating non-application of a filter.
  • the loop filter processing unit 500 acquires the filter number information 31 and the filter information 32 set in step S3100 (step S3101).
  • the filter processing unit 503 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S3101 (step S3102).
  • the loop filter processing unit 500 acquires the block division information 33 set in step S3100 (step S3103).
  • the block division unit 301 divides the local decoded image signal 16 of the coding unit into a plurality of local decoded pixel blocks 35 according to the block division information 33 acquired in step S3103 (step S3104).
  • the loop filter processing unit 500 initializes a counter variable i for counting the processed local decoded pixel block 35 (main block) (step S3105), and the process proceeds to step S3106. Note that the processing in steps S3106 to S3108 is performed in units of main blocks.
  • step S3106 the filter switching unit 302 acquires the filter specifying information 34 corresponding to the (i-th) local decoded pixel block 35 to be processed.
  • the filter switching unit 302 switches the connection of the switch SW so that the processing target local decoded pixel block 35 is supplied to the switch SWx (x is an integer of 1 to n) according to the filter specifying information 34 acquired in step S3106.
  • Step S3107 The loop filter processing unit 500 initializes a counter variable j for counting processed sub-blocks (step S3108), and the process proceeds to step S3109. Note that the processing from step S3109 to step S3114 is performed in units of sub-blocks.
  • step S3109 the loop filter processing unit 500 acquires filter application information 51 corresponding to the j-th sub-block in the i-th main block.
  • the filter application switching unit 510 switches the connection of the switch SWx between the terminal tx and the terminal ux according to the filter application information 51 acquired in step S3109 (step S3110).
  • the filter processing unit 503 acquires a sub-block from the terminal tx or the terminal ut (step S3111). If a sub-block is acquired from terminal tx in step S3111, the process proceeds to step S3113, and if it is acquired from terminal ux, the process proceeds to step S3114.
  • step S3113 the filter processing unit 503 applies the filter Fx to the subblock acquired in step S3111 to output the subblock, and the process proceeds to step S3115.
  • step S3114 the filter processing unit 503 outputs the sub block as it is without applying the filter Fx to the sub block acquired in step S3111, and the process proceeds to step S3115.
  • step S3115 the loop filter processing unit 500 compares the constant NumOfSubBlock indicating the total number of sub blocks in the main block with the value of the counter variable j. If the value of counter variable j is less than the constant NumOfSubBlock, the process proceeds to step S3116; otherwise, the process proceeds to step S3117. In step S3116, the loop filter processing unit 500 increments the counter variable j by 1, and the process returns to step S3109.
  • step S3117 the loop filter processing unit 500 compares the constant NumOfBlock indicating the total number of locally decoded pixel blocks 35 in the coding unit with the value of the counter variable i. If the value of counter variable i is less than the constant NumOfBlock, the process proceeds to step S3118; otherwise, the process proceeds to step S3119. In step S3118, the loop filter processing unit 500 increments the counter variable i by 1, and the process returns to step S3106.
  • the entropy encoding unit 104 entropy-encodes the encoding parameters including the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 set in step S3100 (step S3120). Ends.
  • the filter number information 31, the filter information 32, and the block division information 33 are set in units of slices, the filter specifying information 34 is set in units of main blocks, and the filter application information 51 is set in units of sub blocks.
  • loop filter data syntax 1907 Parameters relating to loop filter processing according to the present embodiment are described in the loop filter data syntax 1907 in FIG. That is, in the loop filter data syntax 1907, as shown in FIG. 17, filter number information 31, filter information 32, block division information 33, filter specifying information 34, and filter application information 51 are described.
  • num_of_filter represents the filter number information 31.
  • filter_coeff [idx] [cy] [cx] is a filter coefficient (that is, at least a part of the filter information 32) at the position of the cy-th row and the cx-th column of the idx-th filter in the filter group.
  • the filter coefficient represents the filter coefficient value itself or difference information as a result of the prediction of the filter coefficient.
  • the filter sizes filter_size_x and filter_size_y are predetermined between the encoding side and the decoding side, but may be set by filter parameters included in the filter information 32. .
  • filter_main_block_size and filter_sub_block_size [i] represent block division information 33.
  • filter_main_block_size represents a division parameter (size of the main block) for dividing the locally decoded image signal 16 of the coding unit into a plurality of main blocks
  • fitler_sub_block_size [i] represents a plurality of i-th main blocks.
  • the block division information 33 may be expressed differently.
  • the block division information 33 may be expressed by an index indicating the size or division mode of the main block or sub block.
  • filter_idx [i] represents the filter specifying information 34 corresponding to the i-th main block.
  • the filter_idx [i] is encoded by commonly used Huffman encoding, arithmetic encoding, or the like.
  • filter_idx [i] may be encoded according to a predetermined variable length table. Note that the variable length table may be switched at a predetermined timing so that a short code is assigned to filter_idx having a high appearance frequency.
  • filter_flag [i] [j] represents filter application information 51 corresponding to the jth sub-block in the i-th main block.
  • the moving picture decoding apparatus corresponds to a configuration in which the loop filter processing unit 400 in the moving picture decoding apparatus of FIG.
  • the same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be mainly described.
  • the entropy decoding unit 201 performs entropy decoding on the code string of the encoded data 14 according to the syntax structure of FIG.
  • the entropy decoding unit 201 generates a quantized transform coefficient 13, filter number information 31, filter information 32, block division information 33, filter identification information 34, filter application information 51, prediction mode, and motion vector from the decoded code string.
  • Demultiplexing decoding parameters such as quantization parameters.
  • the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 according to the syntax of FIG.
  • the entropy decoding unit 201 inputs the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 to the loop filter processing unit 600.
  • the loop filter processing unit 600 includes a block dividing unit 401, a filter switching unit 402, a filter application switching unit 610, a filter processing unit 603, and a block integration unit 404.
  • the loop filter processing unit 600 performs a loop filter process on the decoded image signal 21 in a decoding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 600 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 from the entropy decoding unit 201. .
  • the loop filter processing unit 600 may process an image signal obtained by performing a deblocking filter process on the decoded image signal 21 of a decoding unit.
  • the filter application switching unit 610 switches application / non-application of the filter for each sub-block obtained by further dividing the decoded pixel block 41 (hereinafter also referred to as a main block for convenience) according to the filter application information 51.
  • the filter application information 51 is set for each sub-block.
  • the filter application information 51 specifies application / non-application of the filter selected for the main block according to the filter specifying information 34 for each sub-block.
  • the filter application switching unit 610 is a total of the switches SWn that switch the output destination of each sub-block between the terminal t1 and the terminal u1, and the switch SWn that switches between the terminal tn and the terminal un. Includes n switches.
  • the division parameter for dividing the main block into sub-blocks may be controlled by the block division information 33 or other information, or may be determined in advance on the encoding side and decoding side.
  • the division parameter may be a sub-block size or a division mode (such as quadtree division).
  • the filter processing unit 603 prepares a filter group including the number of filters specified by the filter number information 31 based on the filter information 32, similarly to the filter processing unit 403. That is, the filter processing unit 603 prepares n filters F1,... Fn based on the filter information 32 for each decoding unit. Each filter F1,..., Fn is connected to a terminal t1,. In addition, an unprocessed (bypass) path is connected to the terminals u1,..., Un corresponding to the non-application of the filters F1,. The filter processing unit 603 processes the filters F1,..., Fn on the sub-blocks input from the terminals t1,. The filter processing unit 603 outputs the sub-blocks input from the terminals u1,.
  • the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 (step S4100).
  • the loop filter processing unit 600 acquires the filter number information 31 and the filter information 32 set in step S4100 (step S4101).
  • the filter processing unit 603 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S4101 (step S4102).
  • the loop filter processing unit 600 acquires the block division information 33 set in step S4100 (step S4103).
  • the block division unit 401 divides the decoded image signal 21 of the decoding unit into a plurality of decoded pixel blocks 41 according to the block division information 33 acquired in step S4103 (step S4104).
  • the loop filter processing unit 600 initializes a counter variable i for counting the processed decoded pixel block 41 (main block) (step S4105), and the process proceeds to step S4106. Note that the processing in steps S4106 to S4108 is performed in units of main blocks.
  • step S4106 the filter switching unit 402 acquires the filter specifying information 34 corresponding to the processing target (i-th) decoded pixel block 41.
  • the filter switching unit 402 switches the connection of the switch SW so that the decoding pixel block 41 to be processed is supplied to the switch SWx according to the filter specifying information 34 acquired in step S4106 (step S4107).
  • the loop filter processing unit 600 initializes a counter variable j for counting processed sub-blocks (step S4108), and the process proceeds to step S4109. Note that the processing in steps S4109 to S4114 is performed in units of sub-blocks.
  • step S4109 the loop filter processing unit 600 acquires filter application information 51 corresponding to the j-th sub-block in the i-th main block.
  • the filter application switching unit 610 switches the connection of the switch SWx between the terminal tx and the terminal ux according to the filter application information 51 acquired in step S4109 (step S4110).
  • the filter processing unit 603 acquires a sub-block from the terminal tx or the terminal ut (step S4111). If a sub-block is acquired from terminal tx in step S4111, the process proceeds to step S4113, and if it is acquired from terminal ux, the process proceeds to step S4114.
  • step S4113 the filter processing unit 603 applies the filter Fx to the subblock acquired in step S4111, and outputs the subblock, and the process proceeds to step S4115.
  • step S4114 the filter processing unit 603 outputs the sub block as it is without applying the filter Fx to the sub block acquired in step S4111, and the process proceeds to step S4115.
  • step S4115 the loop filter processing unit 600 compares the constant NumOfSubBlock indicating the total number of sub blocks in the main block with the value of the counter variable j. If the value of counter variable j is less than the constant NumOfSubBlock, the process proceeds to step S4116; otherwise, the process proceeds to step S4117. In step S4116, the loop filter processing unit 600 increments the counter variable j by 1, and the process returns to step S4109.
  • step S4117 the loop filter processing unit 600 compares the constant NumOfBlock indicating the total number of decoded pixel blocks 41 in the decoding unit with the value of the counter variable i. If the value of counter variable i is less than constant NumOfBlock, the process proceeds to step S4118; otherwise, the process proceeds to step S4119. In step S4118, the loop filter processing unit 600 increments the counter variable i by 1, and the process returns to step S4106.
  • step S4119 the block integration unit 404 integrates the restored pixel block 36 (main block), which is a set of sub-blocks processed by the filter processing unit 603, to generate the reference image signal 17 in decoding units, and the processing ends.
  • main block which is a set of sub-blocks processed by the filter processing unit 603, to generate the reference image signal 17 in decoding units, and the processing ends.
  • n 3 as shown in FIG. 14, any one of the filters F1,..., F3 is selected as the main block in the reference image signal 17, and the selected filter is the main block.
  • Application / non-application is determined for each sub-block.
  • the moving image encoding / moving image decoding according to the present embodiment uses filter application information that specifies application / non-application of a filter in units of sub-blocks obtained by further dividing the main block. Therefore, according to the moving image coding / moving image decoding according to the present embodiment, the loop filter processing can be executed locally within the main block, so that the decoding side can efficiently reduce the amount of calculation of the loop filter processing. Image quality can be improved. Moreover, the moving image encoding / moving image decoding according to the present embodiment also has the same effects as those of the first embodiment described above.
  • the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage.
  • Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. Further, for example, a configuration in which some components are deleted from all the components shown in each embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.
  • the moving image encoding device / moving image decoding device may be realized using a general-purpose computer as basic hardware. That is, the prediction signal generation unit 101, the subtractor 102, the transform / quantization unit 103, the entropy encoding unit 104, the inverse transform / inverse quantization unit 105, the adder 106, the encoding control unit 108, the entropy decoding unit 201, The inverse transform / inverse quantization unit 202, the adder 203, the prediction signal generation unit 205, the decoding control unit 206, and the loop filter processing units 300, 400, 500, and 600 execute predetermined programs on a processor mounted on the computer. This can be realized.
  • the reference image buffers 107 and 204 can be realized by appropriately using a storage medium such as a memory, a hard disk, a CD-R, a CD-RW, a DVD-RAM, or a DVD-R built in or external to the computer.
  • a storage medium such as a memory, a hard disk, a CD-R, a CD-RW, a DVD-RAM, or a DVD-R built in or external to the computer.
  • the predetermined program can be provided by being stored in a computer-readable storage medium, for example.
  • Storage media that can store programs and can be read by computers, such as magnetic disks, optical disks (CD-ROM, CD-R, DVD, etc.), magneto-optical disks (MO, etc.), semiconductor memories, etc.
  • the storage format may be any form.
  • a predetermined program may be stored on a computer (server) connected to a network such as the Internet and downloaded to the computer (client) via the network.

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Abstract

Provided is a dynamic image encoding method including: step S1100 for setting block division information containing a parameter for dividing a local decoding image of the encoding unit into a plurality of blocks, filter information containing a filter coefficient of each filter of a filter group for the encoding unit, filter quantity information indicating the number of filters contained in the filter group, and filter identification information for identifying a filter to be applied for each block; steps S1109 and S1112 for applying the filter identified for each block by the filter identification information to each filter so as to generate a reference image; and step S1113 for encoding the filter quantity information, the filter information, the block division information, and the filter identification information.

Description

動画像符号化方法及び動画像復号化方法Video encoding method and video decoding method
　本発明は、動画像の符号化及び復号化に関する。 The present invention relates to encoding and decoding of moving images.
　動画像符号化の国際標準規格の１つであるＨ．２６４／ＭＰＥＧ－４ＡＶＣ（以降、単にＨ．２６４と称する）は、ＩＴＵ－Ｔ（国際電気通信連合電気通信標準化部門）及びＩＳＯ／ＩＥＣ（国際標準化機構／国際電気標準会議）によって共同で策定された。Ｈ．２６４は、ＭＰＥＧ－２の２倍以上という高い圧縮効率を実現している。 H. is one of the international standards for video coding. H.264 / MPEG-4AVC (hereinafter simply referred to as H.264) was jointly established by ITU-T (International Telecommunication Union Telecommunication Standardization Sector) and ISO / IEC (International Organization for Standardization / International Electrotechnical Commission) . H. H.264 achieves a high compression efficiency of more than twice that of MPEG-2.
　Ｈ．２６４では、符号化済みの画像または復号化済みの画像に関する参照画像を予測画像の生成に利用する。参照画像を生成するために、局所復号画像または復号画像に対してループフィルタ処理が行われることがある。具体的には、非特許文献１において開示されているようなデブロッキングフィルタがループフィルタ処理において利用される。デブロッキングフィルタは、局所復号画像または復号画像のブロック境界をぼかすことにより、視覚的に目立つ画質劣化（いわゆるブロック歪）を低減させる。但し、画像を必要以上にぼかすことは、かえって画質劣化を招く。故に、Ｈ．２６４では、処理対象ブロックの予測モード、ブロック境界付近の画素差分値の大きさなどの条件に応じて適応的にデブロッキングフィルタのフィルタ強度を変更する仕組みが採用されている。 H. In H.264, a reference image related to an encoded image or a decoded image is used to generate a predicted image. In order to generate the reference image, a loop filter process may be performed on the local decoded image or the decoded image. Specifically, a deblocking filter as disclosed in Non-Patent Document 1 is used in the loop filter processing. The deblocking filter reduces visually noticeable image quality degradation (so-called block distortion) by blurring the local decoded image or the block boundary of the decoded image. However, blurring an image more than necessary leads to degradation of image quality. Therefore, H.H. H.264 employs a mechanism that adaptively changes the filter strength of the deblocking filter in accordance with conditions such as the prediction mode of the processing target block and the size of the pixel difference value near the block boundary.
　特許文献１記載の画像符号化方法は、複数の画素間フィルタを予め準備しておき、例えばピクチャ毎に選択的にループフィルタ処理を行う。そして、選択した画素間フィルタの情報を復号化側に伝送することにより、符号化／復号化間で共通のループフィルタ処理を実現している。 In the image coding method described in Patent Document 1, a plurality of inter-pixel filters are prepared in advance, and for example, a loop filter process is selectively performed for each picture. Then, the information on the selected inter-pixel filter is transmitted to the decoding side, thereby realizing a common loop filter process between encoding / decoding.
特開２００３－１７９９３３号公報（米国特許出願公開第２００４／０３２９０８号公報）JP 2003-179933 A (US Patent Application Publication No. 2004/032908)
　特許文献１記載の画像符号化方法は、符号化側及び復号化側において複数の画素間フィルタを予め準備する必要がある。例えば、画像の性質（画像サイズ、撮影条件、被写体のテクスチャ、被写体の動きの複雑度など）、圧縮率などのパラメータ次第で、符号化に伴う画質劣化の傾向は異なる。故に、あらゆる条件を予め想定してフィルタを準備することは困難である。仮に、想定される画質劣化の傾向に応じて膨大な数のフィルタを準備するとしても、フィルタの選択情報のオーバヘッド符号量が増大する。また、特許文献１記載の画像符号化方法において、フィルタの選択単位（例えばピクチャ）は固定的である。仮に、画質向上などのためにフィルタの選択単位を小さく設定すると（例えば画素ブロックに設定すると）、フィルタの選択情報のオーバヘッド符号量が増大する。即ち、特許文献１記載の画像符号化方法において、多数のフィルタを準備したり、フィルタの選択単位を小さく設定したりすると、符号化効率が低下する。 In the image encoding method described in Patent Document 1, it is necessary to prepare a plurality of inter-pixel filters in advance on the encoding side and the decoding side. For example, depending on parameters such as image properties (image size, shooting conditions, subject texture, subject motion complexity, etc.), compression rate, and the like, the tendency of image quality degradation accompanying encoding differs. Therefore, it is difficult to prepare a filter assuming all conditions in advance. Even if an enormous number of filters are prepared according to the assumed tendency of image quality degradation, the overhead code amount of the filter selection information increases. In addition, in the image encoding method described in Patent Document 1, the filter selection unit (for example, picture) is fixed. If the filter selection unit is set to be small (for example, set to a pixel block) in order to improve image quality, the overhead code amount of the filter selection information increases. That is, in the image encoding method described in Patent Document 1, if a large number of filters are prepared or the filter selection unit is set small, the encoding efficiency is lowered.
　従って、本発明は、ループフィルタ処理に関するパラメータを高効率に符号化可能な動画像符号化／動画像復号化を提供することを目的とする。 Therefore, an object of the present invention is to provide moving image encoding / moving image decoding capable of encoding parameters relating to loop filter processing with high efficiency.
　本発明の一態様に係る動画像符号化方法は、符号化済みの画像に関する参照画像を利用して予測画像を生成する動画像符号化方法において、符号化単位の局所復号画像を複数のブロックに分割するためのパラメータを含むブロック分割情報を設定することと、前記符号化単位のためのフィルタ群の各フィルタのフィルタ係数を含むフィルタ情報を設定することと、前記フィルタ群に含まれるフィルタの数を示すフィルタ数情報を設定することと、前記ブロック毎に適用すべきフィルタを特定するフィルタ特定情報を設定することと、前記ブロック毎に前記フィルタ特定情報によって特定されるフィルタを適用し、前記参照画像を生成することと、前記フィルタ数情報、前記フィルタ情報、前記ブロック分割情報及び前記フィルタ特定情報を符号化することとを具備する。 A moving image encoding method according to an aspect of the present invention is a moving image encoding method for generating a predicted image using a reference image related to an encoded image, wherein a local decoded image of a coding unit is divided into a plurality of blocks. Setting block division information including parameters for dividing, setting filter information including filter coefficients of each filter of the filter group for the coding unit, and the number of filters included in the filter group Setting filter number information indicating, setting filter specifying information for specifying a filter to be applied to each block, applying a filter specified by the filter specifying information for each block, and Generating an image; and the filter number information, the filter information, the block division information, and the filter specifying information. Comprising a to-coding.
　本発明の他の態様に係る動画像復号化方法は、復号化済みの画像に関する参照画像を利用して予測画像を生成する動画像復号化方法において、復号化単位の復号画像を複数のブロックに分割するためのパラメータを含むブロック分割情報を復号化することと、前記復号化単位のためのフィルタ群に含まれるフィルタの数を示すフィルタ数情報を復号化することと、前記フィルタ群の各フィルタのフィルタ係数を含むフィルタ情報を復号化することと、前記ブロック毎に適用すべきフィルタを特定するフィルタ特定情報を復号化することと、前記ブロック毎に前記フィルタ特定情報によって特定されるフィルタを適用し、前記参照画像を生成することとを具備する。 A moving picture decoding method according to another aspect of the present invention is a moving picture decoding method for generating a predicted picture using a reference picture related to a decoded picture, wherein a decoded picture of a decoding unit is divided into a plurality of blocks. Decoding block division information including parameters for division, decoding filter number information indicating the number of filters included in the filter group for the decoding unit, and each filter of the filter group Decoding the filter information including the filter coefficients, decoding the filter specifying information for specifying the filter to be applied to each block, and applying the filter specified by the filter specifying information for each block And generating the reference image.
　本発明によれば、ループフィルタ処理に関するパラメータを高効率に符号化可能な動画像符号化／動画像復号化を提供できる。 According to the present invention, it is possible to provide moving picture coding / moving picture decoding capable of coding parameters relating to loop filter processing with high efficiency.
第１の実施形態に係る動画像符号化装置を示すブロック図。1 is a block diagram showing a moving image encoding apparatus according to a first embodiment. ループフィルタ処理部３００を示すブロック図。3 is a block diagram showing a loop filter processing unit 300. FIG. 図１の動画像符号化装置の動作を示すフローチャート。The flowchart which shows operation | movement of the moving image encoder of FIG. 第１の実施形態に係る動画像復号化装置を示すブロック図。The block diagram which shows the moving image decoding apparatus which concerns on 1st Embodiment. ループフィルタ処理部４００を示すブロック図。The block diagram which shows the loop filter process part 400. FIG. 図４の動画像復号化装置の動作を示すフローチャート。5 is a flowchart showing the operation of the video decoding device in FIG. 4. 第２の実施形態に係る動画像符号化装置を示すブロック図。The block diagram which shows the moving image encoder which concerns on 2nd Embodiment. ループフィルタ処理部５００を示すブロック図。The block diagram which shows the loop filter process part 500. FIG. 図７の動画像符号化装置の動作を示すフローチャート。The flowchart which shows operation | movement of the moving image encoder of FIG. 図７の動画像符号化装置の動作を示すフローチャート。The flowchart which shows operation | movement of the moving image encoder of FIG. 第２の実施形態に係る動画像復号化装置を示すブロック図。The block diagram which shows the moving image decoding apparatus which concerns on 2nd Embodiment. ループフィルタ処理部６００を示すブロック図。The block diagram which shows the loop filter process part 600. FIG. 図１０の動画像復号化装置の動作を示すフローチャート。11 is a flowchart showing the operation of the video decoding device in FIG. 10. 図１０の動画像復号化装置の動作を示すフローチャート。11 is a flowchart showing the operation of the video decoding device in FIG. 10. 第１の実施形態に係る参照画像信号のフィルタ適用例を示す図。FIG. 5 is a diagram showing an example of filter application of a reference image signal according to the first embodiment. 第２の実施形態に係る参照画像信号のフィルタ適用例を示す図。The figure which shows the example of filter application of the reference image signal which concerns on 2nd Embodiment. 各実施形態に係るシンタクス構造を示す図。The figure which shows the syntax structure which concerns on each embodiment. 第１の実施形態に係るループフィルタデータシンタクスを示す図。The figure which shows the loop filter data syntax which concerns on 1st Embodiment. 第２の実施形態に係るループフィルタデータシンタクスを示す図。The figure which shows the loop filter data syntax which concerns on 2nd Embodiment.
　以下、図面を参照して、本発明の実施形態について説明する。　
　（第１の実施形態）　
　図１に示すように、本発明の第１の実施形態に係る動画像符号化装置は、動画像符号化部１０００及び符号化制御部１０８を有する。動画像符号化部１０００は、予測信号生成部１０１、減算器１０２、変換／量子化部１０３、エントロピー符号化部１０４、逆変換／逆量子化部１０５、加算器１０６、参照画像バッファ１０７及びループフィルタ処理部３００を含む。 Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
As shown in FIG. 1, the moving picture coding apparatus according to the first embodiment of the present invention includes a moving picture coding unit 1000 and a coding control unit 108. The moving image encoding unit 1000 includes a prediction signal generation unit 101, a subtractor 102, a transform / quantization unit 103, an entropy encoding unit 104, an inverse transform / inverse quantization unit 105, an adder 106, a reference image buffer 107, and a loop. A filter processing unit 300 is included.
　予測信号生成部１０１は、参照画像バッファ１０７に保存されている符号化済みの画像に関する参照画像信号１７に基づいて、所定の予測処理を行う。予測信号生成部１０１は、入力画像信号１０の予測画像信号１１を予測処理によって生成し、減算器１０２及び加算器１０６に入力する。予測処理は、動き予測及び動き補償を利用することにより時間的な予測を実現するインター予測方式であってもよいし、周囲の画素値を利用することにより空間的な予測を実現するイントラ予測方式であってもよい。 The prediction signal generation unit 101 performs a predetermined prediction process based on the reference image signal 17 related to the encoded image stored in the reference image buffer 107. The prediction signal generation unit 101 generates a prediction image signal 11 of the input image signal 10 by prediction processing, and inputs the prediction image signal 11 to the subtracter 102 and the adder 106. The prediction process may be an inter prediction method that realizes temporal prediction by using motion prediction and motion compensation, or an intra prediction method that realizes spatial prediction by using surrounding pixel values. It may be.
　減算器１０２は、予測信号生成部１０１からの予測画像信号１１を入力画像信号１０から減算し、予測誤差信号１２を得る。減算器１０２は、予測誤差信号１２を変換／量子化部１０３に入力する。 The subtracter 102 subtracts the prediction image signal 11 from the prediction signal generation unit 101 from the input image signal 10 to obtain a prediction error signal 12. The subtractor 102 inputs the prediction error signal 12 to the transform / quantization unit 103.
　変換／量子化部１０３は、減算器１０２からの予測誤差信号１２を直交変換して、直交変換係数を得る。本実施形態の変換／量子化部１０３は、直交変換として例えばＤＣＴ（Discrete Cosine Transform）を用いる。変換／量子化部１０３は、量子化パラメータに従って直交変換係数を量子化し、量子化された直交変換係数（以降、単に量子化変換係数と称する）１３を得る。量子化パラメータは、符号化制御部１０８によって制御される。変換／量子化部１０３は、量子化変換係数１３をエントロピー符号化部１０４及び逆変換／逆量子化部１０５に入力する。 The transform / quantization unit 103 orthogonally transforms the prediction error signal 12 from the subtractor 102 to obtain an orthogonal transform coefficient. The transform / quantization unit 103 of this embodiment uses, for example, DCT (Discrete Cosine Transform) as orthogonal transform. The transform / quantization unit 103 quantizes the orthogonal transform coefficient according to the quantization parameter to obtain a quantized orthogonal transform coefficient (hereinafter simply referred to as a quantized transform coefficient) 13. The quantization parameter is controlled by the encoding control unit 108. The transform / quantization unit 103 inputs the quantized transform coefficient 13 to the entropy coding unit 104 and the inverse transform / inverse quantization unit 105.
　エントロピー符号化部１０４は、変換／量子化部１０３からの量子化変換係数１３、ループフィルタ処理部３００からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４を符号化パラメータとして取得する。また、エントロピー符号化部１０４は、予測モード、動きベクトル、量子化パラメータなども符号化パラメータとして取得してよい。エントロピー符号化部１０４は、多重化された符号化パラメータにエントロピー符号化（ハフマン符号化または算術符号化）を施し、符号化データ１４を生成して、外部に出力する。 The entropy encoding unit 104 encodes the quantized transform coefficient 13 from the transform / quantization unit 103, the filter number information 31 from the loop filter processing unit 300, the filter information 32, the block division information 33, and the filter identification information 34. Get as. Further, the entropy encoding unit 104 may acquire a prediction mode, a motion vector, a quantization parameter, and the like as encoding parameters. The entropy encoding unit 104 performs entropy encoding (Huffman encoding or arithmetic encoding) on the multiplexed encoding parameter, generates encoded data 14, and outputs the encoded data 14 to the outside.
　逆変換／逆量子化部１０５は、量子化パラメータに従って、量子化変換係数１３を逆量子化し、直交変換係数を復元する。量子化パラメータは、変換／量子化部１０３と同じである。逆変換／逆量子化部１０５は、直交変換係数に対して例えばＩＤＣＴ（Inverse DCT）などの逆直交変換を施し、予測誤差信号１２を復元する。逆直交変換は、変換／量子化部１０３において施された直交変換に対応する。逆変換／逆量子化部１０５は、復元した予測誤差信号１２を予測誤差信号１５として加算器１０６に入力する。 The inverse transform / inverse quantization unit 105 inversely quantizes the quantized transform coefficient 13 according to the quantization parameter to restore the orthogonal transform coefficient. The quantization parameter is the same as that of the transform / quantization unit 103. The inverse transform / inverse quantization unit 105 performs inverse orthogonal transform such as IDCT (Inverse DCT) on the orthogonal transform coefficient to restore the prediction error signal 12. The inverse orthogonal transform corresponds to the orthogonal transform performed in the transform / quantization unit 103. The inverse transform / inverse quantization unit 105 inputs the restored prediction error signal 12 as the prediction error signal 15 to the adder 106.
　加算器１０６は、逆変換／逆量子化部１０５からの予測誤差信号１５と、予測信号生成部１０１からの予測画像信号１１とを加算し、入力画像信号１０を復元する。加算器１０６は、復元した入力画像信号１０を局所復号画像信号１６としてループフィルタ処理部３００に入力する。 The adder 106 adds the prediction error signal 15 from the inverse transform / inverse quantization unit 105 and the prediction image signal 11 from the prediction signal generation unit 101 to restore the input image signal 10. The adder 106 inputs the restored input image signal 10 as the local decoded image signal 16 to the loop filter processing unit 300.
　参照画像バッファ１０７は、ループフィルタ処理部３００からの参照画像信号１７を一時的に保存する。参照画像信号１７は、予測信号生成部１０１によって適宜読み出される。符号化制御部１０８は、動画像符号化部１０００の各構成要素を統括制御する。例えば、符号化制御部１０８は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４をループフィルタ処理部３００に指示する。また、符号化制御部１０８は、発生符号量のフィードバック制御、量子化制御、モード制御などを行う。 The reference image buffer 107 temporarily stores the reference image signal 17 from the loop filter processing unit 300. The reference image signal 17 is appropriately read by the prediction signal generation unit 101. The encoding control unit 108 performs overall control of each component of the moving image encoding unit 1000. For example, the encoding control unit 108 instructs the loop filter processing unit 300 with the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34. Also, the encoding control unit 108 performs feedback control of generated code amount, quantization control, mode control, and the like.
　図２に示すように、ループフィルタ処理部３００は、ブロック分割部３０１、フィルタ切り替え部３０２、フィルタ処理部３０３及びブロック統合部３０４を含む。ループフィルタ処理部３００は、符号化単位（例えば、フレーム、スライスなど）の局所復号画像信号１６に対してループフィルタ処理を行って、参照画像信号１７を得る。より具体的には、ループフィルタ処理部３００は、符号化制御部１０８からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４に従って、ループフィルタ処理を行う。符号化制御部１０８からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４は、エントロピー符号化部１０４にも入力される。尚、ループフィルタ処理部３００は、符号化単位の局所復号画像信号１６にデブロッキングフィルタ処理を施して得られる画像信号を処理してもよい。 2, the loop filter processing unit 300 includes a block dividing unit 301, a filter switching unit 302, a filter processing unit 303, and a block integration unit 304. The loop filter processing unit 300 performs a loop filter process on the local decoded image signal 16 in a coding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 300 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, and the filter identification information 34 from the encoding control unit 108. The number-of-filters information 31, the filter information 32, the block division information 33, and the filter specifying information 34 from the encoding control unit 108 are also input to the entropy encoding unit 104. Note that the loop filter processing unit 300 may process an image signal obtained by performing a deblocking filter process on the local decoded image signal 16 in a coding unit.
　ブロック分割部３０１は、ブロック分割情報３３に従って、局所復号画像信号１６を所定サイズの複数の局所復号画素ブロック３５に分割する。ブロック分割情報３３は、符号化単位毎に設定される。ブロック分割情報３３は、符号化単位の局所復号画像信号１６を所定サイズの複数の局所復号画素ブロック３５に分割するための分割パラメータを示す。分割パラメータは、例えば、上記所定サイズや分割モードを示すパラメータである。ブロック分割部３０１は、局所復号画素ブロック３５をフィルタ切り替え部３０２に入力する。 The block division unit 301 divides the local decoded image signal 16 into a plurality of local decoded pixel blocks 35 having a predetermined size according to the block division information 33. The block division information 33 is set for each coding unit. The block division information 33 indicates a division parameter for dividing the local decoded image signal 16 of a coding unit into a plurality of local decoded pixel blocks 35 having a predetermined size. The division parameter is a parameter indicating the predetermined size or the division mode, for example. The block dividing unit 301 inputs the locally decoded pixel block 35 to the filter switching unit 302.
　フィルタ切り替え部３０２は、フィルタ特定情報３４に従って、局所復号画素ブロック３５のためのフィルタを切り替える。フィルタ特定情報３４は、局所復号画素ブロック３５毎に設定されている。フィルタ特定情報３４は、局所復号画素ブロック３５のために選択されるフィルタを特定する。図２に示すように、フィルタ切り替え部３０２は、局所復号画素ブロック３５の出力先を、端子ｓ1，・・・，ｓn（ｎは自然数）の間で切り替えるスイッチＳＷを含む。 The filter switching unit 302 switches the filter for the local decoded pixel block 35 in accordance with the filter specifying information 34. The filter specifying information 34 is set for each local decoded pixel block 35. The filter specifying information 34 specifies a filter selected for the local decoded pixel block 35. As shown in FIG. 2, the filter switching unit 302 includes a switch SW that switches the output destination of the local decoded pixel block 35 among terminals s1,..., Sn (n is a natural number).
　フィルタ処理部３０３は、フィルタ数情報３１及びフィルタ情報３２に基づいて、各符号化単位のためのフィルタ群を準備する。フィルタ群は少なくとも１つのフィルタを含む。フィルタ数情報３１はフィルタ群に含まれるフィルタの数を示す。フィルタ情報３２は各フィルタのフィルタ係数を示す。フィルタ数情報３１及びフィルタ情報３２は、符号化単位毎に設定される。即ち、フィルタ処理部３０３は、符号化単位毎に、ｎ個のフィルタＦ1，・・・Ｆnを、フィルタ情報３２に基づいて準備する。尚、図２（端子ｓnを含むパス）に示すように、フィルタ処理部３０３は、処理のない（バイパスの）フィルタを準備してもよい。フィルタ処理部３０３は、フィルタ切り替え部３０２によって選択されたフィルタを、局所復号画素ブロック３５に適用し、フィルタリングされた画素ブロック３６を生成する。尚、以降の説明において、フィルタ処理部３０３が準備するフィルタは画像復元フィルタ（例えば、２次元のWiener filter）であるものとし、フィルタリングされた画素ブロック３６は単に復元画素ブロック３６と称する。フィルタ処理部３０３は、復元画素ブロック３６をブロック統合部３０４に入力する。 The filter processing unit 303 prepares a filter group for each coding unit based on the filter number information 31 and the filter information 32. The filter group includes at least one filter. The filter number information 31 indicates the number of filters included in the filter group. The filter information 32 indicates the filter coefficient of each filter. The filter number information 31 and the filter information 32 are set for each coding unit. That is, the filter processing unit 303 prepares n filters F1,... Fn based on the filter information 32 for each encoding unit. As shown in FIG. 2 (path including the terminal sn), the filter processing unit 303 may prepare an unprocessed (bypass) filter. The filter processing unit 303 applies the filter selected by the filter switching unit 302 to the local decoded pixel block 35 to generate a filtered pixel block 36. In the following description, it is assumed that the filter prepared by the filter processing unit 303 is an image restoration filter (for example, a two-dimensional Wiener filter), and the filtered pixel block 36 is simply referred to as a restoration pixel block 36. The filter processing unit 303 inputs the restored pixel block 36 to the block integration unit 304.
　ブロック統合部３０４は、フィルタ処理部３０３からの復元画素ブロック３６を統合し、符号化単位の参照画像信号１７を得る。ブロック統合部３０４は、符号化単位の参照画像信号１７を参照画像バッファ１０７に入力する。 The block integration unit 304 integrates the restored pixel block 36 from the filter processing unit 303 and obtains a reference image signal 17 of a coding unit. The block integration unit 304 inputs the reference image signal 17 of the coding unit to the reference image buffer 107.
　以下、図３を用いて、図１の動画像符号化装置の動作をループフィルタ処理に関連する部分を中心に説明する。　
　まず、符号化制御部１０９は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４を設定する（ステップＳ１１００）。これらフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４は、ユーザが手動で設定してもよいし、所定のアルゴリズムに従って自動で設定されてもよい。 Hereinafter, the operation of the moving picture coding apparatus in FIG. 1 will be described with reference to FIG.
First, the encoding control unit 109 sets the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 (step S1100). The filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 may be set manually by the user or automatically according to a predetermined algorithm.
　フィルタ数情報３１は、各符号化単位において準備されるフィルタの数ｎを示しており、１以上の整数値が設定される。フィルタ特定情報３４は、ｎ個のフィルタに関する選択情報であり、例えばフィルタＦ1，・・・，Ｆnを選択するために、１，・・・，ｎの整数値が夫々設定される。 The filter number information 31 indicates the number n of filters prepared in each coding unit, and an integer value of 1 or more is set. The filter specifying information 34 is selection information regarding n filters. For example, in order to select the filters F1,..., Fn, integer values of 1,.
　フィルタ情報３２は、フィルタＦ1，・・・，Ｆnのフィルタ係数を含む。フィルタＦ1，・・・Ｆnは、２次元のWiener filterであってもよい。Wiener filterは、画像復元において一般的に用いられる。Wiener filterには、参照画像信号１７と入力画像信号１０との間の平均二乗誤差を最小化するためのフィルタ係数が設定される。Wiener filterを用いることにより、符号化側及び復号化側の間で多数の固定フィルタを選択候補として準備する場合に比べて、選択候補の数を削減しつつ効果的に画質を向上させることができる。選択候補の数を削減することにより、フィルタ特定情報３４のオーバヘッド符号量は抑制される。 The filter information 32 includes filter coefficients of the filters F1,. The filters F1,... Fn may be two-dimensional Wiener filters. Wiener filter is generally used in image restoration. A filter coefficient for minimizing the mean square error between the reference image signal 17 and the input image signal 10 is set in Wiener filter. By using the Wiener filter, it is possible to effectively improve the image quality while reducing the number of selection candidates, compared to the case where a large number of fixed filters are prepared as selection candidates between the encoding side and the decoding side. . By reducing the number of selection candidates, the overhead code amount of the filter specifying information 34 is suppressed.
　フィルタ係数以外のフィルタパラメータ（フィルタのタップ長、フィルタの形状、フィルタ係数の対称性、フィルタ係数の量子化ビット精度など）は、符号化側及び復号化側の間で予め規定されていてもよいし、フィルタ情報３２に含められてもよい。このようなフィルタ係数以外のフィルタパラメータをフィルタ情報３２に含める場合には、フィルタパラメータはパラメータ値によって直接表現されてもよいし、インデックスによって表現されてもよい。インデックスによってフィルタパラメータを表現する場合には、符号化側及び復号化側の間で、インデックスをパラメータ値に対応付けた共通のテーブルを予め作成しておく必要がある。フィルタ係数以外のフィルタパラメータをフィルタ情報３２に含めることにより、画質改善性能、フィルタ情報３２の符号量、フィルタ処理の演算量などを符号化側が制御できる。また、シーケンス、フレームなどの単位でフィルタパラメータを適切に制御することにより、符号化効率の向上が可能となる。 Filter parameters other than filter coefficients (filter tap length, filter shape, filter coefficient symmetry, filter coefficient quantization bit precision, etc.) may be defined in advance between the encoding side and the decoding side. However, it may be included in the filter information 32. When such filter parameters other than the filter coefficient are included in the filter information 32, the filter parameter may be directly expressed by a parameter value or may be expressed by an index. When the filter parameter is expressed by an index, a common table in which the index is associated with the parameter value needs to be created in advance between the encoding side and the decoding side. By including filter parameters other than the filter coefficient in the filter information 32, the encoding side can control the image quality improvement performance, the code amount of the filter information 32, the calculation amount of the filter processing, and the like. Also, it is possible to improve the coding efficiency by appropriately controlling the filter parameters in units of sequences, frames, and the like.
　ブロック分割情報３３は、符号化単位の局所復号画像信号１６を所定サイズの複数の局所復号画素ブロック３５に分割するための分割パラメータを示す。例えば、局所復号画素ブロック３５が正方形状であれば、ブロック分割情報３３は局所復号画素ブロック３５の一辺の画素数であってよい。また、ブロック分割情報３３は局所復号画素ブロック３５の形状、サイズ、分割モードなどを示すインデックスであってもよい。ブロック分割情報３３をインデックスで表現する場合には、符号化側及び復号化側の間で、インデックスを局所復号画素ブロック３５の形状、サイズ、分割モードなどに対応付けた共通のテーブルを予め作成しておく必要がある。 The block division information 33 indicates a division parameter for dividing the local decoded image signal 16 of a coding unit into a plurality of local decoded pixel blocks 35 having a predetermined size. For example, if the local decoded pixel block 35 is square, the block division information 33 may be the number of pixels on one side of the local decoded pixel block 35. Further, the block division information 33 may be an index indicating the shape, size, division mode, and the like of the locally decoded pixel block 35. When the block division information 33 is expressed by an index, a common table in which the index is associated with the shape, size, division mode, and the like of the local decoded pixel block 35 is created in advance between the encoding side and the decoding side. It is necessary to keep.
　ループフィルタ処理部３００は、ステップＳ１１００において設定されたフィルタ数情報３１及びフィルタ情報３２を取得する（ステップＳ１１０１）。フィルタ処理部３０３は、ステップＳ１１０１において取得したフィルタ数情報３１及びフィルタ情報３２に基づいて、ｎ個のフィルタＦ1，・・・，Ｆnを設定する（ステップＳ１１０２）。 The loop filter processing unit 300 acquires the filter number information 31 and the filter information 32 set in step S1100 (step S1101). The filter processing unit 303 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S1101 (step S1102).
　ループフィルタ処理部３００は、ステップＳ１１００において設定されたブロック分割情報３３を取得する（ステップＳ１１０３）。ブロック分割部３０１は、ステップＳ１１０３において取得したブロック分割情報３３に従って、符号化単位の局所復号画像信号１６を複数の局所復号画素ブロック３５に分割する（ステップＳ１１０４）。 The loop filter processing unit 300 acquires the block division information 33 set in step S1100 (step S1103). The block division unit 301 divides the local decoded image signal 16 of the coding unit into a plurality of local decoded pixel blocks 35 according to the block division information 33 acquired in step S1103 (step S1104).
　ループフィルタ処理部３００は、処理済みの局所復号画素ブロック３５をカウントするためのカウンタ変数ｉを初期化し（ステップＳ１１０５）、処理はステップＳ１１０６に進む。尚、ステップＳ１１０６～ステップＳ１１０９の処理は、局所復号画素ブロック３５単位で行われる。 The loop filter processing unit 300 initializes a counter variable i for counting the processed local decoded pixel block 35 (step S1105), and the process proceeds to step S1106. Note that the processing of step S1106 to step S1109 is performed in units of local decoded pixel blocks 35.
　ステップＳ１１０６において、フィルタ切り替え部３０２は、処理対象の（第ｉ番目の）局所復号画素ブロック３５に対応するフィルタ特定情報３４を取得する。フィルタ切り替え部３０２は、ステップＳ１１０６において取得したフィルタ特定情報３４に従って、処理対象の局所復号画素ブロック３５がフィルタＦ1，・・・，Ｆnのいずれかに供給されるようにスイッチＳＷの接続を切り替える（ステップＳ１１０７）。 In step S1106, the filter switching unit 302 acquires the filter specifying information 34 corresponding to the (i-th) local decoded pixel block 35 to be processed. The filter switching unit 302 switches the connection of the switch SW so that the local decoded pixel block 35 to be processed is supplied to one of the filters F1,..., Fn according to the filter specifying information 34 acquired in step S1106 ( Step S1107).
　フィルタ処理部３０３は、フィルタ切り替え部３０２から処理対象の局所復号画素ブロック３５を取得する（ステップＳ１１０８）。フィルタ処理部３０３は、ステップＳ１１０７におけるスイッチＳＷの接続に従って、ステップＳ１１０８において取得した局所復号画素ブロック３５にフィルタＦ1，・・・，Ｆnのいずれかを適用し、復元画素ブロック３６を生成して（ステップＳ１１０９）、処理はステップＳ１１１０に進む。 The filter processing unit 303 acquires the local decoded pixel block 35 to be processed from the filter switching unit 302 (step S1108). The filter processing unit 303 applies one of the filters F1,..., Fn to the local decoded pixel block 35 acquired in step S1108 according to the connection of the switch SW in step S1107, and generates the restored pixel block 36 ( In step S1109), the process proceeds to step S1110.
　ステップＳ１１１０において、ループフィルタ処理部３００は、符号化単位内における局所復号画素ブロック３５の総数を示す定数NumOfBlockと、カウンタ変数ｉの値とを比較する。カウンタ変数ｉの値が定数NumOfBlock未満であれば処理はステップＳ１１１１に進み、そうでなければ処理はステップＳ１１１２に進む。ステップＳ１１１１において、ループフィルタ処理部３００はカウンタ変数ｉを１だけインクリメントし、処理はステップＳ１１０６に戻る。 In step S1110, the loop filter processing unit 300 compares the constant NumOfBlock indicating the total number of locally decoded pixel blocks 35 in the coding unit with the value of the counter variable i. If the value of counter variable i is less than the constant NumOfBlock, the process proceeds to step S1111; otherwise, the process proceeds to step S1112. In step S1111, the loop filter processing unit 300 increments the counter variable i by 1, and the process returns to step S1106.
　ステップＳ１１１２において、ブロック統合部３０４は、復元画素ブロック３６を統合し、符号化単位の参照画像信号１７を生成する。例えばｎ＝３であれば、図１３に示すように、参照画像信号１７内の復元画素ブロック３６には、フィルタＦ1，・・・，Ｆ3のいずれかが夫々適用されている。 In step S1112, the block integration unit 304 integrates the restored pixel block 36 and generates the reference image signal 17 of the coding unit. For example, if n = 3, as shown in FIG. 13, one of the filters F1,..., F3 is applied to the restored pixel block 36 in the reference image signal 17, respectively.
　エントロピー符号化部１０４はステップＳ１１００において設定されたフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４を含む符号化パラメータをエントロピー符号化し（ステップＳ１１１３）、処理が終了する。 The entropy encoding unit 104 entropy encodes the encoding parameters including the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 set in step S1100 (step S1113), and the process ends.
　以下、本実施形態に係る動画像符号化／動画像復号化において利用されるシンタクスについて説明する。尚、以降の説明ではフィルタ数情報３１、フィルタ情報３２及びブロック分割情報３３はスライス単位で設定され、フィルタ特定情報３４は画素ブロック単位で設定されるものとする。 Hereinafter, syntax used in moving picture coding / moving picture decoding according to the present embodiment will be described. In the following description, the filter number information 31, the filter information 32, and the block division information 33 are set in units of slices, and the filter specifying information 34 is set in units of pixel blocks.
　図１５に示すように、シンタクスは３つのパートで構成される。ハイレベルシンタクス１９００には、スライス以上の上位レイヤのパラメータが記述される。スライスレベルシンタクス１９０３には、スライス毎のパラメータが記述される。マクロブロックレベルシンタクス１９０７には、マクロブロック毎のパラメータ（量子化変換係数１３、予測モード、動きベクトルなど）が記述される。 As shown in FIG. 15, the syntax is composed of three parts. High-level syntax 1900 describes parameters of higher layers above the slice. The slice level syntax 1903 describes parameters for each slice. The macro block level syntax 1907 describes parameters (quantized transform coefficient 13, prediction mode, motion vector, etc.) for each macro block.
　ハイレベルシンタクス１９００は、シーケンスパラメータセットシンタクス１９０１及びピクチャパラメータセットシンタクス１９０２を含む。シーケンスパラメータセットシンタクス１９０１には、シーケンス毎のパラメータが記述される。ピクチャパラメータセットシンタクス１９０２は、ピクチャ毎のパラメータが記述される。 The high level syntax 1900 includes a sequence parameter set syntax 1901 and a picture parameter set syntax 1902. The sequence parameter set syntax 1901 describes parameters for each sequence. The picture parameter set syntax 1902 describes parameters for each picture.
　スライスレベルシンタクス１９０３は、スライスヘッダーシンタクス１９０４、スライスデータシンタクス１９０５及びループフィルタデータシンタクス１９０６を含む。マクロブロックレベルシンタクス１９０７は、マクロブロックレイヤーシンタクス１９０８及びマクロブロックプレディクションシンタクス１９０９を含む。 The slice level syntax 1903 includes a slice header syntax 1904, a slice data syntax 1905, and a loop filter data syntax 1906. The macroblock level syntax 1907 includes a macroblock layer syntax 1908 and a macroblock prediction syntax 1909.
　本実施形態に係るループフィルタ処理に関するパラメータは、図１５におけるループフィルタデータシンタクス１９０７に記述される。即ち、ループフィルタデータシンタクス１９０７には、図１６に示すように、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４が記述される。 Parameters relating to loop filter processing according to the present embodiment are described in the loop filter data syntax 1907 in FIG. That is, in the loop filter data syntax 1907, as shown in FIG. 16, filter number information 31, filter information 32, block division information 33, and filter specifying information 34 are described.
　図１６において、num_of_filterはフィルタ数情報３１を表す。図１６において、filter_coeff[idx][cy][cx]は、フィルタ群のうちの第idx番目のフィルタの第cy行第cx列の位置のフィルタ係数（即ち、フィルタ情報３２の少なくとも一部）を表す。尚、フィルタ係数は、フィルタ係数の値そのもの、あるいは、フィルタ係数の予測を行った結果の差分情報を表現する。尚、図１６の例においては、フィルタのサイズfilter_size_x及びfilter_size_yは、符号化側及び復号化側の間で予め定められているものとするが、フィルタ情報３２に含まれるフィルタパラメータによって設定されてもよい。図１６において、filter_block_sizeはブロック分割情報３３を表す。図１６において、filter_idx[i]は第ｉ番目の画素ブロックに対応するフィルタ特定情報３４を表す。filter_idx[i]は、一般に用いられるハフマン符号化、算術符号化などによって符号化される。また、filter_idx[i]は、所定の可変長テーブルに従って符号化されてもよい。尚、出現頻度の高いfilter_idxに短い符号が割り当てられるように、所定のタイミングで可変長テーブルが切り替えられてもよい。また、前述のように、フィルタ係数以外のフィルタパラメータ（フィルタのタップ長、フィルタの形状、フィルタ係数の対称性、フィルタ係数の量子化ビット精度など）が、図１６のシンタクスにおいて更に記述されてもよい。 In FIG. 16, num_of_filter represents the filter number information 31. In FIG. 16, filter_coeff [idx] [cy] [cx] is a filter coefficient (that is, at least a part of the filter information 32) at the position of the cy-th row and the cx-th column of the idx-th filter in the filter group. To express. The filter coefficient represents the filter coefficient value itself or difference information as a result of the prediction of the filter coefficient. In the example of FIG. 16, the filter sizes filter_size_x and filter_size_y are predetermined between the encoding side and the decoding side, but may be set by the filter parameter included in the filter information 32. Good. In FIG. 16, filter_block_size represents block division information 33. In FIG. 16, filter_idx [i] represents the filter specifying information 34 corresponding to the i-th pixel block. The filter_idx [i] is encoded by commonly used Huffman encoding, arithmetic encoding, or the like. Also, filter_idx [i] may be encoded according to a predetermined variable length table. Note that the variable length table may be switched at a predetermined timing so that a short code is assigned to filter_idx having a high appearance frequency. Further, as described above, filter parameters other than the filter coefficient (filter tap length, filter shape, filter coefficient symmetry, filter coefficient quantization bit precision, etc.) may be further described in the syntax of FIG. Good.
　図４に示すように、本実施形態に係る動画像復号化装置は、動画像復号化部２０００及び復号化制御部２０６を有する。動画像復号化部２０００は、エントロピー復号化部２０１、逆変換／逆量子化部２０２、加算器２０３、参照画像バッファ２０４、予測信号生成部２０５及びループフィルタ処理部４００を含む。 As shown in FIG. 4, the moving picture decoding apparatus according to the present embodiment includes a moving picture decoding unit 2000 and a decoding control unit 206. The moving picture decoding unit 2000 includes an entropy decoding unit 201, an inverse transform / inverse quantization unit 202, an adder 203, a reference image buffer 204, a prediction signal generation unit 205, and a loop filter processing unit 400.
　エントロピー復号化部２０１は、図１５のシンタクス構造に従って、符号化データ１４の符号列をエントロピー復号化する。エントロピー復号化部２０１は、復号化された符号列から、量子化変換係数１３、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４、予測モード、動きベクトル、量子化パラメータなどの復号化パラメータを逆多重化する。具体的には、エントロピー復号化部２０１は、図１６のシンタクスに従って、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４を復号化する。エントロピー復号化部２０１は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４をループフィルタ処理部４００に入力する。 The entropy decoding unit 201 performs entropy decoding on the code string of the encoded data 14 according to the syntax structure of FIG. From the decoded code string, the entropy decoding unit 201 performs quantization transform coefficient 13, filter number information 31, filter information 32, block division information 33, filter identification information 34, prediction mode, motion vector, quantization parameter, and the like. Are demultiplexed. Specifically, the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 according to the syntax of FIG. The entropy decoding unit 201 inputs the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 to the loop filter processing unit 400.
　逆変換／逆量子化部２０２は、エントロピー復号化部２０１からの量子化変換係数１３を量子化パラメータに従って逆量子化し、直交変換係数を復元する。量子化パラメータは、エントロピー復号化部２０１によって復号化される。逆変換／逆量子化部２０２は、直交変換係数に対して逆直交変換を施して、予測誤差信号１５を得る。逆変換／逆量子化部２０２は、予測誤差信号１５を加算器２０３に入力する。 The inverse transform / inverse quantization unit 202 dequantizes the quantized transform coefficient 13 from the entropy decoding unit 201 according to the quantization parameter, and restores the orthogonal transform coefficient. The quantization parameter is decoded by the entropy decoding unit 201. The inverse transform / inverse quantization unit 202 performs inverse orthogonal transform on the orthogonal transform coefficient to obtain the prediction error signal 15. The inverse transform / inverse quantization unit 202 inputs the prediction error signal 15 to the adder 203.
　加算器２０３は、予測信号生成部２０５からの予測画像信号１１と、逆変換／逆量子化部２０２からの予測誤差信号１５とを加算し、復号画像信号２１を生成する。参照画像バッファ２０４は、ループフィルタ処理部４００からの参照画像信号１７を一時的に保存する。参照画像信号１７は、予測信号生成部２０５によって適宜読み出される。 The adder 203 adds the prediction image signal 11 from the prediction signal generation unit 205 and the prediction error signal 15 from the inverse transform / inverse quantization unit 202 to generate a decoded image signal 21. The reference image buffer 204 temporarily stores the reference image signal 17 from the loop filter processing unit 400. The reference image signal 17 is appropriately read out by the prediction signal generation unit 205.
　予測信号生成部２０５は、参照画像バッファ２０４に保存されている復号化済みの画像に関する参照画像信号１７に基づき、予測モード、動きベクトルなどに応じた予測処理（イントラ予測処理、インター予測処理など）を行って、予測画像信号１１を生成する。予測モード及び動きベクトルは、エントロピー復号化部２０１によって復号化される。予測信号生成部２０５は、予測画像信号１１を加算器２０３に入力する。　
　復号化制御部２０６は、動画像復号化部２０００の各構成要素を統括制御する。例えば、復号化制御部２０６は、復号化タイミングを制御する。 The prediction signal generation unit 205 performs prediction processing (intra prediction processing, inter prediction processing, etc.) according to a prediction mode, a motion vector, and the like based on the reference image signal 17 related to the decoded image stored in the reference image buffer 204. To generate the predicted image signal 11. The prediction mode and the motion vector are decoded by the entropy decoding unit 201. The predicted signal generation unit 205 inputs the predicted image signal 11 to the adder 203.
The decoding control unit 206 performs overall control of each component of the moving image decoding unit 2000. For example, the decoding control unit 206 controls the decoding timing.
　図５に示すように、ループフィルタ処理部４００は、ブロック分割部４０１、フィルタ切り替え部４０２、フィルタ処理部４０３及びブロック統合部４０４を含む。ループフィルタ処理部４００は、復号化単位（例えば、フレーム、スライスなど）の復号画像信号２１に対してループフィルタ処理を行って、参照画像信号１７を得る。より具体的には、ループフィルタ処理部４００は、エントロピー復号化部２０１からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４に従って、ループフィルタ処理を行う。尚、ループフィルタ処理部４００は、復号化単位の復号画像信号２１にデブロッキングフィルタ処理を施して得られる画像信号を処理してもよい。 As shown in FIG. 5, the loop filter processing unit 400 includes a block dividing unit 401, a filter switching unit 402, a filter processing unit 403, and a block integration unit 404. The loop filter processing unit 400 performs a loop filter process on the decoded image signal 21 of a decoding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 400 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 from the entropy decoding unit 201. Note that the loop filter processing unit 400 may process an image signal obtained by performing a deblocking filter process on the decoded image signal 21 of a decoding unit.
　ブロック分割部４０１は、ブロック分割情報３３に従って、復号画像信号２１を所定サイズの複数の復号画素ブロック４１に分割する。ブロック分割情報３３は、復号化単位毎に設定されている。ブロック分割情報３３は、復号化単位の復号画像信号２１を所定サイズの複数の復号画素ブロック４１に分割するための分割パラメータ（例えば、上記所定サイズ、分割モードなど）を示す。ブロック分割部４０１は、復号画素ブロック４１をフィルタ切り替え部４０２に入力する。 The block division unit 401 divides the decoded image signal 21 into a plurality of decoded pixel blocks 41 having a predetermined size according to the block division information 33. The block division information 33 is set for each decoding unit. The block division information 33 indicates a division parameter (for example, the predetermined size, the division mode, etc.) for dividing the decoded image signal 21 of a decoding unit into a plurality of decoded pixel blocks 41 having a predetermined size. The block division unit 401 inputs the decoded pixel block 41 to the filter switching unit 402.
　フィルタ切り替え部４０２は、フィルタ特定情報３４に従って、復号画素ブロック４１のためのフィルタを切り替える。フィルタ特定情報３４は、復号画素ブロック４１毎に設定されている。フィルタ特定情報３４は、復号画素ブロック４１のために選択されるフィルタを特定する。図５に示すように、フィルタ切り替え部４０２は、復号画素ブロック４１の出力先を、端子ｓ1，・・・，ｓnの間で切り替えるスイッチＳＷを含む。 The filter switching unit 402 switches the filter for the decoded pixel block 41 in accordance with the filter specifying information 34. The filter specifying information 34 is set for each decoded pixel block 41. The filter specifying information 34 specifies a filter selected for the decoded pixel block 41. As shown in FIG. 5, the filter switching unit 402 includes a switch SW that switches the output destination of the decoded pixel block 41 between the terminals s1, ..., sn.
　フィルタ処理部４０３は、フィルタ数情報３１及びフィルタ情報３２に基づいて、各復号化単位のためのフィルタ群を準備する。フィルタ群は少なくとも１つのフィルタを含む。フィルタ数情報３１はフィルタ群に含まれるフィルタの数を示す。フィルタ情報３２は各フィルタのフィルタ係数を示す。フィルタ数情報３１及びフィルタ情報３２は、復号化単位毎に設定されている。即ち、フィルタ処理部４０３は、復号化単位毎に、ｎ個のフィルタＦ1，・・・Ｆnを、フィルタ情報３２に基づいて準備する。尚、図５（端子ｓnを含むパス）に示すように、フィルタ処理部４０３は、処理のない（バイパスの）フィルタを準備することもある。フィルタ処理部４０３は、フィルタ切り替え部４０２によって選択されたフィルタを、復号画素ブロック４１に適用し、復元画素ブロック３６を生成する。フィルタ処理部４０３は、復元画素ブロック３６をブロック統合部４０４に入力する。 The filter processing unit 403 prepares a filter group for each decoding unit based on the filter number information 31 and the filter information 32. The filter group includes at least one filter. The filter number information 31 indicates the number of filters included in the filter group. The filter information 32 indicates the filter coefficient of each filter. The filter number information 31 and the filter information 32 are set for each decoding unit. That is, the filter processing unit 403 prepares n filters F1,... Fn based on the filter information 32 for each decoding unit. As shown in FIG. 5 (path including the terminal sn), the filter processing unit 403 may prepare an unprocessed (bypass) filter. The filter processing unit 403 applies the filter selected by the filter switching unit 402 to the decoded pixel block 41 to generate the restored pixel block 36. The filter processing unit 403 inputs the restored pixel block 36 to the block integration unit 404.
　ブロック統合部４０４は、フィルタ処理部４０３からの復元画素ブロック３６を統合し、復号化単位の参照画像信号１７を得る。ブロック統合部４０４は、復号化単位の参照画像信号１７を参照画像バッファ２０４に入力する。 The block integration unit 404 integrates the restored pixel block 36 from the filter processing unit 403 and obtains a reference image signal 17 of a decoding unit. The block integration unit 404 inputs the reference image signal 17 of the decoding unit to the reference image buffer 204.
　以下、図６を用いて、図４の動画像復号化装置の動作をループフィルタ処理に関連する部分を中心に説明する。　
　まず、エントロピー復号化部２０１は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３及びフィルタ特定情報３４を復号化する（ステップＳ２１００）。 Hereinafter, the operation of the video decoding device in FIG. 4 will be described with reference to FIG.
First, the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, and the filter specifying information 34 (step S2100).
　ループフィルタ処理部４００は、ステップＳ２１００において設定されたフィルタ数情報３１及びフィルタ情報３２を取得する（ステップＳ２１０１）。フィルタ処理部４０３は、ステップＳ２１０１において取得したフィルタ数情報３１及びフィルタ情報３２に基づいて、ｎ個のフィルタＦ1，・・・，Ｆnを設定する（ステップＳ２１０２）。 The loop filter processing unit 400 acquires the filter number information 31 and the filter information 32 set in step S2100 (step S2101). The filter processing unit 403 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S2101 (step S2102).
　ループフィルタ処理部４００は、ステップＳ２１００において設定されたブロック分割情報３３を取得する（ステップＳ２１０３）。ブロック分割部４０１は、ステップＳ２１０３において取得したブロック分割情報３３に従って、復号化単位の復号画像信号２１を複数の復号画素ブロック４１に分割する（ステップＳ２１０４）。 The loop filter processing unit 400 acquires the block division information 33 set in step S2100 (step S2103). The block division unit 401 divides the decoded image signal 21 of the decoding unit into a plurality of decoded pixel blocks 41 according to the block division information 33 acquired in step S2103 (step S2104).
　ループフィルタ処理部４００は、処理済みの復号画素ブロック４１をカウントするためのカウンタ変数ｉを初期化し（ステップＳ２１０５）、処理はステップＳ２１０６に進む。尚、ステップＳ２１０６～ステップＳ２１０９の処理は、復号画素ブロック４１単位で行われる。 The loop filter processing unit 400 initializes a counter variable i for counting the processed decoded pixel block 41 (step S2105), and the process proceeds to step S2106. Note that the processing from step S2106 to step S2109 is performed for each decoded pixel block 41.
　ステップＳ２１０６において、フィルタ切り替え部４０２は、処理対象の（第ｉ番目の）復号画素ブロック４１に対応するフィルタ特定情報３４を取得する。フィルタ切り替え部４０２は、ステップＳ２１０６において取得したフィルタ特定情報３４に従って、処理対象の復号画素ブロック４１がフィルタＦ1，・・・，Ｆnのいずれかに供給されるようにスイッチＳＷの接続を切り替える（ステップＳ２１０７）。 In step S2106, the filter switching unit 402 acquires the filter specifying information 34 corresponding to the (i-th) decoded pixel block 41 to be processed. The filter switching unit 402 switches the connection of the switch SW so that the decoding pixel block 41 to be processed is supplied to one of the filters F1,..., Fn according to the filter specifying information 34 acquired in Step S2106 (Step S2106). S2107).
　フィルタ処理部４０３は、フィルタ切り替え部４０２から処理対象の復号画素ブロック４１を取得する（ステップＳ２１０８）。フィルタ処理部４０３は、ステップＳ２１０７におけるスイッチＳＷの接続に従って、ステップＳ２１０８において取得した復号画素ブロック４１にフィルタＦ1，・・・，Ｆnのいずれかを適用し、復元画素ブロック３６を生成し（ステップＳ２１０９）、処理はステップＳ２１１０に進む。 The filter processing unit 403 acquires the decoded pixel block 41 to be processed from the filter switching unit 402 (step S2108). The filter processing unit 403 applies one of the filters F1,..., Fn to the decoded pixel block 41 acquired in step S2108 according to the connection of the switch SW in step S2107, and generates the restored pixel block 36 (step S2109). ), The process proceeds to step S2110.
　ステップＳ２１１０において、ループフィルタ処理部４００は、復号化単位内における復号画素ブロック４１の総数を示す定数NumOfBlockと、カウンタ変数ｉの値とを比較する。カウンタ変数ｉの値が定数NumOfBlock未満であれば処理はステップＳ２１１１に進み、そうでなければ処理はステップＳ２１１２に進む。ステップＳ２１１１において、ループフィルタ処理部４００はカウンタ変数ｉを１だけインクリメントし、処理はステップＳ２１０６に戻る。 In step S2110, the loop filter processing unit 400 compares the constant NumOfBlock indicating the total number of decoded pixel blocks 41 in the decoding unit with the value of the counter variable i. If the value of counter variable i is less than the constant NumOfBlock, the process proceeds to step S2111; otherwise, the process proceeds to step S2112. In step S2111, the loop filter processing unit 400 increments the counter variable i by 1, and the process returns to step S2106.
　ステップＳ２１１２において、ブロック統合部４０４は復元画素ブロック３６を統合し、復号化単位の参照画像信号１７を生成し、処理が終了する。例えばｎ＝３であれば、図１３に示すように、参照画像信号１７内の復元画素ブロック３６には、フィルタＦ1，・・・，Ｆ3のいずれかが夫々適用されている。 In step S2112, the block integration unit 404 integrates the restored pixel block 36, generates a reference image signal 17 of a decoding unit, and the process ends. For example, if n = 3, as shown in FIG. 13, one of the filters F1,..., F3 is applied to the restored pixel block 36 in the reference image signal 17, respectively.
　以上説明したように、本実施形態に係る動画像符号化／動画像復号化は、符号化／復号化単位で準備するフィルタの数、フィルタの選択単位などを符号化側において任意に設定している。従って、本実施形態に係る動画像符号化／動画像復号化によれば、ループフィルタ処理に関するオーバヘッド符号量を要求されるビットレートなどに応じて制御し、ループフィルタ処理に関するパラメータを高効率に符号化できる。具体的には、フィルタ数情報３１が示すフィルタの数を増減させることにより、フィルタ情報３２（及びフィルタ特定情報３４）の符号量が制御可能である。また、ブロック分割情報３３が示す分割パラメータを変更することにより、フィルタ特定情報３４の符号量が制御可能である。 As described above, in the video encoding / video decoding according to the present embodiment, the number of filters prepared in the encoding / decoding unit, the filter selection unit, and the like are arbitrarily set on the encoding side. Yes. Therefore, according to the moving image encoding / moving image decoding according to the present embodiment, the overhead code amount related to the loop filter processing is controlled according to the required bit rate and the like, and the parameters related to the loop filter processing are encoded with high efficiency. Can be Specifically, the code amount of the filter information 32 (and the filter specifying information 34) can be controlled by increasing or decreasing the number of filters indicated by the filter number information 31. Further, the code amount of the filter specifying information 34 can be controlled by changing the division parameter indicated by the block division information 33.
　（第２の実施形態）　
　図７に示すように、本発明の第２の実施形態に係る動画像符号化装置は、図１の動画像符号化装置におけるループフィルタ処理部３００をループフィルタ処理部５００に置き換えた構成に相当する。以下の説明では、第１の実施形態と同一部分には同一符号を付して示し、異なる部分を中心に述べる。 (Second Embodiment)
As shown in FIG. 7, the moving picture coding apparatus according to the second embodiment of the present invention corresponds to a configuration in which the loop filter processing unit 300 in the moving picture coding apparatus of FIG. To do. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be mainly described.
　エントロピー符号化部１０４は、変換／量子化部１０３からの量子化変換係数１３、ループフィルタ処理部３００からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１を符号化パラメータとして取得する。また、エントロピー符号化部１０４は、予測モード、動きベクトル、量子化パラメータなども符号化パラメータとして取得してよい。エントロピー符号化部１０４は、多重化された符号化パラメータにエントロピー符号化を施し、符号化データ１４を生成して、外部に出力する。 The entropy encoding unit 104 includes the quantized transform coefficient 13 from the transform / quantization unit 103, the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information from the loop filter processing unit 300. 51 is acquired as an encoding parameter. Further, the entropy encoding unit 104 may acquire a prediction mode, a motion vector, a quantization parameter, and the like as encoding parameters. The entropy encoding unit 104 performs entropy encoding on the multiplexed encoding parameter, generates encoded data 14 and outputs the encoded data 14 to the outside.
　図８に示すように、ループフィルタ処理部５００は、ブロック分割部３０１、フィルタ切り替え部３０２、フィルタ適用切り替え部５１０、フィルタ処理部５０３及びブロック統合部３０４を含む。ループフィルタ処理部５００は、符号化単位（例えば、フレーム、スライスなど）の局所復号画像信号１６に対してループフィルタ処理を行って、参照画像信号１７を得る。より具体的には、ループフィルタ処理部５００は、符号化制御部１０８からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１に従って、ループフィルタ処理を行う。符号化制御部１０８からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１は、エントロピー符号化部１０４にも入力される。尚、ループフィルタ処理部５００は、符号化単位の局所復号画像信号１６にデブロッキングフィルタ処理を施して得られる画像信号を処理してもよい。 As shown in FIG. 8, the loop filter processing unit 500 includes a block dividing unit 301, a filter switching unit 302, a filter application switching unit 510, a filter processing unit 503, and a block integration unit 304. The loop filter processing unit 500 performs a loop filter process on the local decoded image signal 16 in a coding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 500 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 from the encoding control unit 108. . The filter number information 31, the filter information 32, the block division information 33, the filter identification information 34, and the filter application information 51 from the encoding control unit 108 are also input to the entropy encoding unit 104. Note that the loop filter processing unit 500 may process an image signal obtained by performing a deblocking filter process on the local decoded image signal 16 in a coding unit.
　フィルタ適用切り替え部５１０は、フィルタ適用情報５１に従って、局所復号画素ブロック３５（以降、便宜的にメインブロックとも称する）を更に分割したサブブロック毎にフィルタの適用／非適用を切り替える。フィルタ適用情報５１は、サブブロック毎に設定されている。フィルタ適用情報５１は、フィルタ特定情報３４に従ってメインブロックのために選択されたフィルタの適用／非適用をサブブロック毎に指定する。図８に示すように、フィルタ適用切り替え部５１０は、各サブブロックの出力先を端子ｔ1及び端子ｕ1の間で切り替えるスイッチＳＷ1，・・・，端子ｔn及び端子ｕnの間で切り替えるスイッチＳＷnの合計ｎ個のスイッチを含む。尚、メインブロックをサブブロックに分割するための分割パラメータは、ブロック分割情報３３またはその他の情報によって制御されてもよいし、符号化側及び復号化側において予め定められてもよい。分割パラメータは、サブブロックのサイズであってもよいし、分割モード（４分木分割など）であってもよい。 The filter application switching unit 510 switches application / non-application of the filter for each sub-block obtained by further dividing the local decoded pixel block 35 (hereinafter also referred to as a main block for convenience) according to the filter application information 51. The filter application information 51 is set for each sub-block. The filter application information 51 specifies application / non-application of the filter selected for the main block according to the filter specifying information 34 for each sub-block. As shown in FIG. 8, the filter application switching unit 510 is a total of the switches SWn for switching the output destination of each sub-block between the terminal t1 and the terminal u1, and the switch SWn for switching between the terminal tn and the terminal un. Includes n switches. The division parameter for dividing the main block into sub-blocks may be controlled by the block division information 33 or other information, or may be determined in advance on the encoding side and decoding side. The division parameter may be a sub-block size or a division mode (such as quadtree division).
　フィルタ処理部５０３は、フィルタ処理部３０３と同様に、フィルタ数情報３１によって指定される数のフィルタを含むフィルタ群を、フィルタ情報３２に基づいて準備する。即ち、フィルタ処理部５０３は、符号化単位毎に、ｎ個のフィルタＦ1，・・・Ｆnを、フィルタ情報３２に基づいて準備する。各フィルタＦ1，・・・，Ｆnは、フィルタの適用に対応する端子ｔ1，・・・，ｔnに夫々接続される。また、各フィルタＦ1，・・・，Ｆnの非適用に対応する端子ｕ1，・・・，ｕnには処理のない（バイパス）経路が接続される。フィルタ処理部５０３は、端子ｔ1，・・・，ｔnから入力されたサブブロックに対してフィルタＦ1，・・・，Ｆnの処理を行って出力する。フィルタ処理部５０３は、端子ｕ1，・・・，ｕnから入力されたサブブロックをそのまま出力する。 The filter processing unit 503 prepares a filter group including the number of filters specified by the filter number information 31 based on the filter information 32, similarly to the filter processing unit 303. That is, the filter processing unit 503 prepares n filters F1,... Fn based on the filter information 32 for each encoding unit. Each filter F1,..., Fn is connected to a terminal t1,. In addition, an unprocessed (bypass) path is connected to the terminals u1,..., Un corresponding to the non-application of the filters F1,. The filter processing unit 503 processes the filters F1,..., Fn on the sub-blocks input from the terminals t1,. The filter processing unit 503 outputs the sub-blocks input from the terminals u1,.
　以下、図９Ａ及び図９Ｂを用いて、図７の動画像符号化装置の動作をループフィルタ処理に関連する部分を中心に説明する。　
　まず、符号化制御部１０９は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１を設定する（ステップＳ３１００）。これらフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１は、ユーザが手動で設定してもよいし、所定のアルゴリズムに従って自動で設定されてもよい。 Hereinafter, the operation of the moving picture coding apparatus in FIG. 7 will be described with reference to FIGS. 9A and 9B, focusing on portions related to loop filter processing.
First, the encoding control unit 109 sets the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 (step S3100). The filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 may be set manually by the user or automatically according to a predetermined algorithm.
　フィルタ適用情報５１は、フィルタ特定情報３４に従ってメインブロックのために選択されたフィルタのサブブロック単位での適用／非適用を指定するパラメータである。フィルタ適用情報５１の値は、例えば、フィルタの適用を示す場合に１、フィルタの非適用を示す場合に０である。 The filter application information 51 is a parameter that specifies application / non-application of the filter selected for the main block in accordance with the filter identification information 34 in units of sub-blocks. The value of the filter application information 51 is, for example, 1 when indicating application of a filter, and 0 when indicating non-application of a filter.
　ループフィルタ処理部５００は、ステップＳ３１００において設定されたフィルタ数情報３１及びフィルタ情報３２を取得する（ステップＳ３１０１）。フィルタ処理部５０３は、ステップＳ３１０１において取得したフィルタ数情報３１及びフィルタ情報３２に基づいて、ｎ個のフィルタＦ1，・・・，Ｆnを設定する（ステップＳ３１０２）。 The loop filter processing unit 500 acquires the filter number information 31 and the filter information 32 set in step S3100 (step S3101). The filter processing unit 503 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S3101 (step S3102).
　ループフィルタ処理部５００は、ステップＳ３１００において設定されたブロック分割情報３３を取得する（ステップＳ３１０３）。ブロック分割部３０１は、ステップＳ３１０３において取得したブロック分割情報３３に従って、符号化単位の局所復号画像信号１６を複数の局所復号画素ブロック３５に分割する（ステップＳ３１０４）。 The loop filter processing unit 500 acquires the block division information 33 set in step S3100 (step S3103). The block division unit 301 divides the local decoded image signal 16 of the coding unit into a plurality of local decoded pixel blocks 35 according to the block division information 33 acquired in step S3103 (step S3104).
　ループフィルタ処理部５００は、処理済みの局所復号画素ブロック３５（メインブロック）をカウントするためのカウンタ変数ｉを初期化し（ステップＳ３１０５）、処理はステップＳ３１０６に進む。尚、ステップＳ３１０６～ステップＳ３１０８の処理は、メインブロック単位で行われる。 The loop filter processing unit 500 initializes a counter variable i for counting the processed local decoded pixel block 35 (main block) (step S3105), and the process proceeds to step S3106. Note that the processing in steps S3106 to S3108 is performed in units of main blocks.
　ステップＳ３１０６において、フィルタ切り替え部３０２は、処理対象の（第ｉ番目の）局所復号画素ブロック３５に対応するフィルタ特定情報３４を取得する。フィルタ切り替え部３０２は、ステップＳ３１０６において取得したフィルタ特定情報３４に従って、処理対象の局所復号画素ブロック３５がスイッチＳＷx（xは１以上ｎ以下の整数）に供給されるようにスイッチＳＷの接続を切り替える（ステップＳ３１０７）。ループフィルタ処理部５００は処理済みのサブブロックをカウントするためのカウンタ変数ｊを初期化し（ステップＳ３１０８）、処理はステップＳ３１０９に進む。尚、ステップＳ３１０９～ステップＳ３１１４の処理は、サブブロック単位で行われる。 In step S3106, the filter switching unit 302 acquires the filter specifying information 34 corresponding to the (i-th) local decoded pixel block 35 to be processed. The filter switching unit 302 switches the connection of the switch SW so that the processing target local decoded pixel block 35 is supplied to the switch SWx (x is an integer of 1 to n) according to the filter specifying information 34 acquired in step S3106. (Step S3107). The loop filter processing unit 500 initializes a counter variable j for counting processed sub-blocks (step S3108), and the process proceeds to step S3109. Note that the processing from step S3109 to step S3114 is performed in units of sub-blocks.
　ステップＳ３１０９において、ループフィルタ処理部５００は第ｉ番目のメインブロック内の第ｊ番目のサブブロックに対応するフィルタ適用情報５１を取得する。フィルタ適用切り替え部５１０は、ステップＳ３１０９において取得したフィルタ適用情報５１に従って、スイッチＳＷxの接続を端子ｔx及び端子ｕxの間で切り替える（ステップＳ３１１０）。 In step S3109, the loop filter processing unit 500 acquires filter application information 51 corresponding to the j-th sub-block in the i-th main block. The filter application switching unit 510 switches the connection of the switch SWx between the terminal tx and the terminal ux according to the filter application information 51 acquired in step S3109 (step S3110).
　フィルタ処理部５０３は、端子ｔxまたは端子ｕtからサブブロックを取得する（ステップＳ３１１１）。ステップＳ３１１１においてサブブロックが端子ｔxから取得されていれば処理はステップＳ３１１３に進み、端子ｕxから取得されていれば処理はステップＳ３１１４に進む。 The filter processing unit 503 acquires a sub-block from the terminal tx or the terminal ut (step S3111). If a sub-block is acquired from terminal tx in step S3111, the process proceeds to step S3113, and if it is acquired from terminal ux, the process proceeds to step S3114.
　ステップＳ３１１３において、フィルタ処理部５０３はステップＳ３１１１において取得したサブブロックに対してフィルタＦxを適用してサブブロックを出力し、処理はステップＳ３１１５に進む。ステップＳ３１１４において、フィルタ処理部５０３はステップＳ３１１１において取得したサブブロックに対してフィルタＦxを適用せずにサブブロックをそのまま出力し、処理はステップＳ３１１５に進む。 In step S3113, the filter processing unit 503 applies the filter Fx to the subblock acquired in step S3111 to output the subblock, and the process proceeds to step S3115. In step S3114, the filter processing unit 503 outputs the sub block as it is without applying the filter Fx to the sub block acquired in step S3111, and the process proceeds to step S3115.
　ステップＳ３１１５において、ループフィルタ処理部５００は、メインブロック内におけるサブブロックの総数を示す定数NumOfSubBlockと、カウンタ変数ｊの値とを比較する。カウンタ変数ｊの値が定数NumOfSubBlock未満であれば処理はステップＳ３１１６に進み、そうでなければ処理はステップＳ３１１７に進む。ステップＳ３１１６において、ループフィルタ処理部５００はカウンタ変数ｊを１だけインクリメントし、処理はステップＳ３１０９に戻る。 In step S3115, the loop filter processing unit 500 compares the constant NumOfSubBlock indicating the total number of sub blocks in the main block with the value of the counter variable j. If the value of counter variable j is less than the constant NumOfSubBlock, the process proceeds to step S3116; otherwise, the process proceeds to step S3117. In step S3116, the loop filter processing unit 500 increments the counter variable j by 1, and the process returns to step S3109.
　ステップＳ３１１７において、ループフィルタ処理部５００は、符号化単位内における局所復号画素ブロック３５の総数を示す定数NumOfBlockと、カウンタ変数ｉの値とを比較する。カウンタ変数ｉの値が定数NumOfBlock未満であれば処理はステップＳ３１１８に進み、そうでなければ処理はステップＳ３１１９に進む。ステップＳ３１１８において、ループフィルタ処理部５００はカウンタ変数ｉを１だけインクリメントし、処理はステップＳ３１０６に戻る。 In step S3117, the loop filter processing unit 500 compares the constant NumOfBlock indicating the total number of locally decoded pixel blocks 35 in the coding unit with the value of the counter variable i. If the value of counter variable i is less than the constant NumOfBlock, the process proceeds to step S3118; otherwise, the process proceeds to step S3119. In step S3118, the loop filter processing unit 500 increments the counter variable i by 1, and the process returns to step S3106.
　ステップＳ３１１９において、ブロック統合部３０４は、フィルタ処理部５０３によって処理されたサブブロックの集合である復元画素ブロック３６（メインブロック）を統合し、符号化単位の参照画像信号１７を生成する。例えば、ｎ＝３であれば、図１４に示すように、参照画像信号１７内のメインブロックにはフィルタＦ1，・・・，Ｆ3のいずれかが夫々選択され、この選択されたフィルタはメインブロック内のサブブロック毎に適用／非適用が定められる。 In step S3119, the block integration unit 304 integrates the restored pixel block 36 (main block), which is a set of sub-blocks processed by the filter processing unit 503, and generates a reference image signal 17 in encoding units. For example, if n = 3, as shown in FIG. 14, any one of the filters F1,..., F3 is selected as the main block in the reference image signal 17, and the selected filter is the main block. Application / non-application is determined for each sub-block.
　エントロピー符号化部１０４はステップＳ３１００において設定されたフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１を含む符号化パラメータをエントロピー符号化し（ステップＳ３１２０）、処理が終了する。 The entropy encoding unit 104 entropy-encodes the encoding parameters including the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 set in step S3100 (step S3120). Ends.
　以下、本実施形態に係る動画像符号化／動画像復号化において利用されるシンタクスについて説明する。尚、以降の説明ではフィルタ数情報３１、フィルタ情報３２及びブロック分割情報３３はスライス単位で設定され、フィルタ特定情報３４はメインブロック単位で設定され、フィルタ適用情報５１はサブブロック単位で設定されるものとする。 Hereinafter, syntax used in moving picture coding / moving picture decoding according to the present embodiment will be described. In the following description, the filter number information 31, the filter information 32, and the block division information 33 are set in units of slices, the filter specifying information 34 is set in units of main blocks, and the filter application information 51 is set in units of sub blocks. Shall.
　本実施形態に係るループフィルタ処理に関するパラメータは、図１５におけるループフィルタデータシンタクス１９０７に記述される。即ち、ループフィルタデータシンタクス１９０７には、図１７に示すように、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１が記述される。 Parameters relating to loop filter processing according to the present embodiment are described in the loop filter data syntax 1907 in FIG. That is, in the loop filter data syntax 1907, as shown in FIG. 17, filter number information 31, filter information 32, block division information 33, filter specifying information 34, and filter application information 51 are described.
　図１７において、num_of_filterはフィルタ数情報３１を表す。図１７において、filter_coeff[idx][cy][cx]は、フィルタ群のうちの第idx番目のフィルタの第cy行第cx列の位置のフィルタ係数（即ち、フィルタ情報３２の少なくとも一部）を表す。尚、フィルタ係数は、フィルタ係数の値そのもの、あるいは、フィルタ係数の予測を行った結果の差分情報を表現する。尚、図１７の例において、フィルタのサイズfilter_size_x及びfilter_size_yは、符号化側及び復号化側の間で予め定められているものとするが、フィルタ情報３２に含まれるフィルタパラメータによって設定されてもよい。図１７において、filter_main_block_size及びfilter_sub_block_size[i]はブロック分割情報３３を表す。具体的には、filter_main_block_sizeは符号化単位の局所復号画像信号１６を複数のメインブロックに分割するための分割パラメータ（メインブロックのサイズ）を表し、fitler_sub_block_size[i]は第ｉ番目のメインブロックを複数のサブブロックに分割するための分割パラメータ（サブブロックのサイズ）を表す。尚、ブロック分割情報３３は、異なる表現であってもよい。例えば、ブロック分割情報３３はメインブロックまたはサブブロックのサイズまたは分割モードを示すインデックスで表現されてもよい。尚、ブロック分割情報３３をインデックスで表現する場合には、符号化側及び復号化側の間で、インデックスをメインブロックまたはサブブロックのサイズまたは分割モードに対応付けた共通のテーブルを予め作成しておく必要がある。図１７において、filter_idx[i]は第ｉ番目のメインブロックに対応するフィルタ特定情報３４を表す。filter_idx[i]は、一般に用いられるハフマン符号化、算術符号化などによって符号化される。また、filter_idx[i]は、所定の可変長テーブルに従って符号化されてもよい。尚、出現頻度の高いfilter_idxに短い符号が割り当てられるように、所定のタイミングで可変長テーブルが切り替えられてもよい。また、前述のように、フィルタ係数以外のフィルタパラメータ（フィルタのタップ長、フィルタの形状、フィルタ係数の対称性、フィルタ係数の量子化ビット精度など）が、図１７のシンタクスにおいて更に記述されてもよい。図１７において、filter_flag[i][j]は、第ｉ番目のメインブロック内の第ｊ番目のサブブロックに対応するフィルタ適用情報５１を表す。 In FIG. 17, num_of_filter represents the filter number information 31. In FIG. 17, filter_coeff [idx] [cy] [cx] is a filter coefficient (that is, at least a part of the filter information 32) at the position of the cy-th row and the cx-th column of the idx-th filter in the filter group. To express. The filter coefficient represents the filter coefficient value itself or difference information as a result of the prediction of the filter coefficient. In the example of FIG. 17, the filter sizes filter_size_x and filter_size_y are predetermined between the encoding side and the decoding side, but may be set by filter parameters included in the filter information 32. . In FIG. 17, filter_main_block_size and filter_sub_block_size [i] represent block division information 33. Specifically, filter_main_block_size represents a division parameter (size of the main block) for dividing the locally decoded image signal 16 of the coding unit into a plurality of main blocks, and fitler_sub_block_size [i] represents a plurality of i-th main blocks. Represents a division parameter (subblock size) for dividing the subblock. The block division information 33 may be expressed differently. For example, the block division information 33 may be expressed by an index indicating the size or division mode of the main block or sub block. When the block division information 33 is expressed as an index, a common table in which the index is associated with the size of the main block or sub block or the division mode is created in advance between the encoding side and the decoding side. It is necessary to keep. In FIG. 17, filter_idx [i] represents the filter specifying information 34 corresponding to the i-th main block. The filter_idx [i] is encoded by commonly used Huffman encoding, arithmetic encoding, or the like. Also, filter_idx [i] may be encoded according to a predetermined variable length table. Note that the variable length table may be switched at a predetermined timing so that a short code is assigned to filter_idx having a high appearance frequency. Further, as described above, filter parameters other than filter coefficients (filter tap length, filter shape, filter coefficient symmetry, filter coefficient quantization bit precision, etc.) may be further described in the syntax of FIG. Good. In FIG. 17, filter_flag [i] [j] represents filter application information 51 corresponding to the jth sub-block in the i-th main block.
　図１０に示すように、本実施形態に係る動画像復号化装置は、図４の動画像復号化装置におけるループフィルタ処理部４００をループフィルタ処理部６００に置き換えた構成に相当する。以下の説明では、第の実施形態と同一部分には同一符号を付して示し、異なる部分を中心に述べる。 As shown in FIG. 10, the moving picture decoding apparatus according to this embodiment corresponds to a configuration in which the loop filter processing unit 400 in the moving picture decoding apparatus of FIG. In the following description, the same parts as those in the first embodiment are denoted by the same reference numerals, and different parts will be mainly described.
　エントロピー復号化部２０１は、図１５のシンタクス構造に従って、符号化データ１４の符号列をエントロピー復号化する。エントロピー復号化部２０１は、復号化された符号列から、量子化変換係数１３、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４、フィルタ適用情報５１、予測モード、動きベクトル、量子化パラメータなどの復号化パラメータを逆多重化する。具体的には、エントロピー復号化部２０１は、図１７のシンタクスに従って、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１を復号化する。エントロピー復号化部２０１は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１をループフィルタ処理部６００に入力する。 The entropy decoding unit 201 performs entropy decoding on the code string of the encoded data 14 according to the syntax structure of FIG. The entropy decoding unit 201 generates a quantized transform coefficient 13, filter number information 31, filter information 32, block division information 33, filter identification information 34, filter application information 51, prediction mode, and motion vector from the decoded code string. Demultiplexing decoding parameters such as quantization parameters. Specifically, the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 according to the syntax of FIG. The entropy decoding unit 201 inputs the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 to the loop filter processing unit 600.
　図１１に示すように、ループフィルタ処理部６００は、ブロック分割部４０１、フィルタ切り替え部４０２、フィルタ適用切り替え部６１０、フィルタ処理部６０３及びブロック統合部４０４を含む。ループフィルタ処理部６００は、復号化単位（例えば、フレーム、スライスなど）の復号画像信号２１に対してループフィルタ処理を行って、参照画像信号１７を得る。より具体的には、ループフィルタ処理部６００は、エントロピー復号化部２０１からのフィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１に従って、ループフィルタ処理を行う。尚、ループフィルタ処理部６００は、復号化単位の復号画像信号２１にデブロッキングフィルタ処理を施して得られる画像信号を処理してもよい。 11, the loop filter processing unit 600 includes a block dividing unit 401, a filter switching unit 402, a filter application switching unit 610, a filter processing unit 603, and a block integration unit 404. The loop filter processing unit 600 performs a loop filter process on the decoded image signal 21 in a decoding unit (for example, a frame, a slice, etc.) to obtain a reference image signal 17. More specifically, the loop filter processing unit 600 performs loop filter processing according to the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 from the entropy decoding unit 201. . Note that the loop filter processing unit 600 may process an image signal obtained by performing a deblocking filter process on the decoded image signal 21 of a decoding unit.
　フィルタ適用切り替え部６１０は、フィルタ適用情報５１に従って、復号画素ブロック４１（以降、便宜的にメインブロックとも称する）を更に分割したサブブロック毎にフィルタの適用／非適用を切り替える。フィルタ適用情報５１は、サブブロック毎に設定されている。フィルタ適用情報５１は、フィルタ特定情報３４に従ってメインブロックのために選択されたフィルタの適用／非適用をサブブロック毎に指定する。図１１に示すように、フィルタ適用切り替え部６１０は、各サブブロックの出力先を端子ｔ1及び端子ｕ1の間で切り替えるスイッチＳＷ1，・・・，端子ｔn及び端子ｕnの間で切り替えるスイッチＳＷnの合計ｎ個のスイッチを含む。尚、メインブロックをサブブロックに分割するための分割パラメータは、ブロック分割情報３３またはその他の情報によって制御されてもよいし、符号化側及び復号化側において予め定められてもよい。分割パラメータは、サブブロックのサイズであってもよいし、分割モード（４分木分割など）であってもよい。 The filter application switching unit 610 switches application / non-application of the filter for each sub-block obtained by further dividing the decoded pixel block 41 (hereinafter also referred to as a main block for convenience) according to the filter application information 51. The filter application information 51 is set for each sub-block. The filter application information 51 specifies application / non-application of the filter selected for the main block according to the filter specifying information 34 for each sub-block. As shown in FIG. 11, the filter application switching unit 610 is a total of the switches SWn that switch the output destination of each sub-block between the terminal t1 and the terminal u1, and the switch SWn that switches between the terminal tn and the terminal un. Includes n switches. The division parameter for dividing the main block into sub-blocks may be controlled by the block division information 33 or other information, or may be determined in advance on the encoding side and decoding side. The division parameter may be a sub-block size or a division mode (such as quadtree division).
　フィルタ処理部６０３は、フィルタ処理部４０３と同様に、フィルタ数情報３１によって指定される数のフィルタを含むフィルタ群を、フィルタ情報３２に基づいて準備する。即ち、フィルタ処理部６０３は、復号化単位毎に、ｎ個のフィルタＦ1，・・・Ｆnを、フィルタ情報３２に基づいて準備する。各フィルタＦ1，・・・，Ｆnは、フィルタの適用に対応する端子ｔ1，・・・，ｔnに夫々接続される。また、各フィルタＦ1，・・・，Ｆnの非適用に対応する端子ｕ1，・・・，ｕnには処理のない（バイパス）経路が接続される。フィルタ処理部６０３は、端子ｔ1，・・・，ｔnから入力されたサブブロックに対してフィルタＦ1，・・・，Ｆnの処理を行って出力する。フィルタ処理部６０３は、端子ｕ1，・・・，ｕnから入力されたサブブロックをそのまま出力する。 The filter processing unit 603 prepares a filter group including the number of filters specified by the filter number information 31 based on the filter information 32, similarly to the filter processing unit 403. That is, the filter processing unit 603 prepares n filters F1,... Fn based on the filter information 32 for each decoding unit. Each filter F1,..., Fn is connected to a terminal t1,. In addition, an unprocessed (bypass) path is connected to the terminals u1,..., Un corresponding to the non-application of the filters F1,. The filter processing unit 603 processes the filters F1,..., Fn on the sub-blocks input from the terminals t1,. The filter processing unit 603 outputs the sub-blocks input from the terminals u1,.
　以下、図１２Ａ及び図１２Ｂを用いて、図１０の動画像復号化装置の動作をループフィルタ処理に関連する部分を中心に説明する。　
　まず、エントロピー復号化部２０１は、フィルタ数情報３１、フィルタ情報３２、ブロック分割情報３３、フィルタ特定情報３４及びフィルタ適用情報５１を復号化する（ステップＳ４１００）。 Hereinafter, the operation of the video decoding device in FIG. 10 will be described with reference to FIGS. 12A and 12B, focusing on the portion related to the loop filter processing.
First, the entropy decoding unit 201 decodes the filter number information 31, the filter information 32, the block division information 33, the filter specifying information 34, and the filter application information 51 (step S4100).
　ループフィルタ処理部６００は、ステップＳ４１００において設定されたフィルタ数情報３１及びフィルタ情報３２を取得する（ステップＳ４１０１）。フィルタ処理部６０３は、ステップＳ４１０１において取得したフィルタ数情報３１及びフィルタ情報３２に基づいて、ｎ個のフィルタＦ1，・・・，Ｆnを設定する（ステップＳ４１０２）。 The loop filter processing unit 600 acquires the filter number information 31 and the filter information 32 set in step S4100 (step S4101). The filter processing unit 603 sets n filters F1,..., Fn based on the filter number information 31 and the filter information 32 acquired in step S4101 (step S4102).
　ループフィルタ処理部６００は、ステップＳ４１００において設定されたブロック分割情報３３を取得する（ステップＳ４１０３）。ブロック分割部４０１は、ステップＳ４１０３において取得したブロック分割情報３３に従って、復号化単位の復号画像信号２１を複数の復号画素ブロック４１に分割する（ステップＳ４１０４）。 The loop filter processing unit 600 acquires the block division information 33 set in step S4100 (step S4103). The block division unit 401 divides the decoded image signal 21 of the decoding unit into a plurality of decoded pixel blocks 41 according to the block division information 33 acquired in step S4103 (step S4104).
　ループフィルタ処理部６００は、処理済みの復号画素ブロック４１（メインブロック）をカウントするためのカウンタ変数ｉを初期化し（ステップＳ４１０５）、処理はステップＳ４１０６に進む。尚、ステップＳ４１０６～ステップＳ４１０８の処理は、メインブロック単位で行われる。 The loop filter processing unit 600 initializes a counter variable i for counting the processed decoded pixel block 41 (main block) (step S4105), and the process proceeds to step S4106. Note that the processing in steps S4106 to S4108 is performed in units of main blocks.
　ステップＳ４１０６において、フィルタ切り替え部４０２は、処理対象の（第ｉ番目の）復号画素ブロック４１に対応するフィルタ特定情報３４を取得する。フィルタ切り替え部４０２は、ステップＳ４１０６において取得したフィルタ特定情報３４に従って、処理対象の復号画素ブロック４１がスイッチＳＷxに供給されるようにスイッチＳＷの接続を切り替える（ステップＳ４１０７）。ループフィルタ処理部６００は処理済みのサブブロックをカウントするためのカウンタ変数ｊを初期化し（ステップＳ４１０８）、処理はステップＳ４１０９に進む。尚、ステップＳ４１０９～ステップＳ４１１４の処理は、サブブロック単位で行われる。 In step S4106, the filter switching unit 402 acquires the filter specifying information 34 corresponding to the processing target (i-th) decoded pixel block 41. The filter switching unit 402 switches the connection of the switch SW so that the decoding pixel block 41 to be processed is supplied to the switch SWx according to the filter specifying information 34 acquired in step S4106 (step S4107). The loop filter processing unit 600 initializes a counter variable j for counting processed sub-blocks (step S4108), and the process proceeds to step S4109. Note that the processing in steps S4109 to S4114 is performed in units of sub-blocks.
　ステップＳ４１０９において、ループフィルタ処理部６００は第ｉ番目のメインブロック内の第ｊ番目のサブブロックに対応するフィルタ適用情報５１を取得する。フィルタ適用切り替え部６１０は、ステップＳ４１０９において取得したフィルタ適用情報５１に従って、スイッチＳＷxの接続を端子ｔx及び端子ｕxの間で切り替える（ステップＳ４１１０）。 In step S4109, the loop filter processing unit 600 acquires filter application information 51 corresponding to the j-th sub-block in the i-th main block. The filter application switching unit 610 switches the connection of the switch SWx between the terminal tx and the terminal ux according to the filter application information 51 acquired in step S4109 (step S4110).
　フィルタ処理部６０３は、端子ｔxまたは端子ｕtからサブブロックを取得する（ステップＳ４１１１）。ステップＳ４１１１においてサブブロックが端子ｔxから取得されていれば処理はステップＳ４１１３に進み、端子ｕxから取得されていれば処理はステップＳ４１１４に進む。 The filter processing unit 603 acquires a sub-block from the terminal tx or the terminal ut (step S4111). If a sub-block is acquired from terminal tx in step S4111, the process proceeds to step S4113, and if it is acquired from terminal ux, the process proceeds to step S4114.
　ステップＳ４１１３において、フィルタ処理部６０３はステップＳ４１１１において取得したサブブロックに対してフィルタＦxを適用してサブブロックを出力し、処理はステップＳ４１１５に進む。ステップＳ４１１４において、フィルタ処理部６０３はステップＳ４１１１において取得したサブブロックに対してフィルタＦxを適用せずにサブブロックをそのまま出力し、処理はステップＳ４１１５に進む。 In step S4113, the filter processing unit 603 applies the filter Fx to the subblock acquired in step S4111, and outputs the subblock, and the process proceeds to step S4115. In step S4114, the filter processing unit 603 outputs the sub block as it is without applying the filter Fx to the sub block acquired in step S4111, and the process proceeds to step S4115.
　ステップＳ４１１５において、ループフィルタ処理部６００は、メインブロック内におけるサブブロックの総数を示す定数NumOfSubBlockと、カウンタ変数ｊの値とを比較する。カウンタ変数ｊの値が定数NumOfSubBlock未満であれば処理はステップＳ４１１６に進み、そうでなければ処理はステップＳ４１１７に進む。ステップＳ４１１６において、ループフィルタ処理部６００はカウンタ変数ｊを１だけインクリメントし、処理はステップＳ４１０９に戻る。 In step S4115, the loop filter processing unit 600 compares the constant NumOfSubBlock indicating the total number of sub blocks in the main block with the value of the counter variable j. If the value of counter variable j is less than the constant NumOfSubBlock, the process proceeds to step S4116; otherwise, the process proceeds to step S4117. In step S4116, the loop filter processing unit 600 increments the counter variable j by 1, and the process returns to step S4109.
　ステップＳ４１１７において、ループフィルタ処理部６００は、復号化単位内における復号画素ブロック４１の総数を示す定数NumOfBlockと、カウンタ変数ｉの値とを比較する。カウンタ変数ｉの値が定数NumOfBlock未満であれば処理はステップＳ４１１８に進み、そうでなければ処理はステップＳ４１１９に進む。ステップＳ４１１８において、ループフィルタ処理部６００はカウンタ変数ｉを１だけインクリメントし、処理はステップＳ４１０６に戻る。 In step S4117, the loop filter processing unit 600 compares the constant NumOfBlock indicating the total number of decoded pixel blocks 41 in the decoding unit with the value of the counter variable i. If the value of counter variable i is less than constant NumOfBlock, the process proceeds to step S4118; otherwise, the process proceeds to step S4119. In step S4118, the loop filter processing unit 600 increments the counter variable i by 1, and the process returns to step S4106.
　ステップＳ４１１９において、ブロック統合部４０４はフィルタ処理部６０３によって処理されたサブブロックの集合である復元画素ブロック３６（メインブロック）を統合して復号化単位の参照画像信号１７を生成し、処理が終了する。例えば、ｎ＝３であれば、図１４に示すように、参照画像信号１７内のメインブロックにはフィルタＦ1，・・・，Ｆ3のいずれかが夫々選択され、この選択されたフィルタはメインブロック内のサブブロック毎に適用／非適用が定められる。 In step S4119, the block integration unit 404 integrates the restored pixel block 36 (main block), which is a set of sub-blocks processed by the filter processing unit 603, to generate the reference image signal 17 in decoding units, and the processing ends. To do. For example, if n = 3, as shown in FIG. 14, any one of the filters F1,..., F3 is selected as the main block in the reference image signal 17, and the selected filter is the main block. Application / non-application is determined for each sub-block.
　以上説明したように、本実施形態に係る動画像符号化／動画像復号化は、メインブロックを更に分割したサブブロック単位でフィルタの適用／非適用を指定するフィルタ適用情報を使用する。従って、本実施形態に係る動画像符号化／動画像復号化によれば、メインブロック内で局所的にループフィルタ処理を実行できるので、復号化側はループフィルタ処理の演算量を削減しつつ効率的に画質を改善できる。また、本実施形態に係る動画像符号化／動画像復号化は、前述した第１の実施形態と同様の効果も奏する。 As described above, the moving image encoding / moving image decoding according to the present embodiment uses filter application information that specifies application / non-application of a filter in units of sub-blocks obtained by further dividing the main block. Therefore, according to the moving image coding / moving image decoding according to the present embodiment, the loop filter processing can be executed locally within the main block, so that the decoding side can efficiently reduce the amount of calculation of the loop filter processing. Image quality can be improved. Moreover, the moving image encoding / moving image decoding according to the present embodiment also has the same effects as those of the first embodiment described above.
　尚、本発明は上記各実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また上記各実施形態に開示されている複数の構成要素を適宜組み合わせることによって種々の発明を形成できる。また例えば、各実施形態に示される全構成要素からいくつかの構成要素を削除した構成も考えられる。さらに、異なる実施形態に記載した構成要素を適宜組み合わせてもよい。 Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. Further, for example, a configuration in which some components are deleted from all the components shown in each embodiment is also conceivable. Furthermore, you may combine suitably the component described in different embodiment.
　例えば、各実施形態に係る動画像符号化装置／動画像復号化装置を汎用のコンピュータを基本ハードウェアとして用いて実現してもよい。即ち、予測信号生成部１０１、減算器１０２、変換／量子化部１０３、エントロピー符号化部１０４、逆変換／逆量子化部１０５、加算器１０６、符号化制御部１０８、エントロピー復号化部２０１、逆変換／逆量子化部２０２、加算器２０３、予測信号生成部２０５、復号化制御部２０６及びループフィルタ処理部３００，４００，５００，６００は、コンピュータに搭載されたプロセッサに所定のプログラムを実行させることにより実現できる。また、参照画像バッファ１０７，２０４は、コンピュータに内蔵または外付けされたメモリ、ハードディスク、ＣＤ－Ｒ、ＣＤ－ＲＷ、ＤＶＤ－ＲＡＭ、ＤＶＤ－Ｒなどの記憶媒体を適宜利用して実現できる。 For example, the moving image encoding device / moving image decoding device according to each embodiment may be realized using a general-purpose computer as basic hardware. That is, the prediction signal generation unit 101, the subtractor 102, the transform / quantization unit 103, the entropy encoding unit 104, the inverse transform / inverse quantization unit 105, the adder 106, the encoding control unit 108, the entropy decoding unit 201, The inverse transform / inverse quantization unit 202, the adder 203, the prediction signal generation unit 205, the decoding control unit 206, and the loop filter processing units 300, 400, 500, and 600 execute predetermined programs on a processor mounted on the computer. This can be realized. The reference image buffers 107 and 204 can be realized by appropriately using a storage medium such as a memory, a hard disk, a CD-R, a CD-RW, a DVD-RAM, or a DVD-R built in or external to the computer.
　所定のプログラムは、例えばコンピュータで読み取り可能な記憶媒体に格納して提供できる。記憶媒体としては、磁気ディスク、光ディスク（ＣＤ－ＲＯＭ、ＣＤ－Ｒ、ＤＶＤなど）、光磁気ディスク（ＭＯなど）、半導体メモリなど、プログラムを記憶可能であって、かつ、コンピュータが読み取り可能な記憶媒体であれば、その記憶形式は何れの形態であってもよい。また、所定のプログラムを、インターネットなどのネットワークに接続されたコンピュータ（サーバ）上に格納し、ネットワーク経由でコンピュータ（クライアント）にダウンロードさせてもよい。 The predetermined program can be provided by being stored in a computer-readable storage medium, for example. Storage media that can store programs and can be read by computers, such as magnetic disks, optical disks (CD-ROM, CD-R, DVD, etc.), magneto-optical disks (MO, etc.), semiconductor memories, etc. As long as it is a medium, the storage format may be any form. A predetermined program may be stored on a computer (server) connected to a network such as the Internet and downloaded to the computer (client) via the network.
　１０・・・入力画像信号
　１１・・・予測画像信号
　１２・・・予測誤差信号
　１３・・・量子化変換係数
　１４・・・符号化データ
　１５・・・予測誤差信号
　１６・・・局所復号画像信号
　１７・・・参照画像信号
　２１・・・復号画像信号
　３１・・・フィルタ数情報
　３２・・・フィルタ情報
　３３・・・ブロック分割情報
　３４・・・フィルタ特定情報
　３５・・・局所復号画素ブロック
　３６・・・復元画素ブロック
　４１・・・復号画素ブロック
　５１・・・フィルタ適用情報
　１０１・・・予測信号生成部
　１０２・・・減算器
　１０３・・・変換／量子化部
　１０４・・・エントロピー符号化部
　１０５・・・逆変換／逆量子化部
　１０６・・・加算器
　１０７・・・参照画像バッファ
　１０８・・・符号化制御部
　２０１・・・エントロピー復号化部
　２０２・・・逆変換／逆量子化部
　２０３・・・加算器
　２０４・・・予測信号生成部
　２０５・・・参照画像バッファ
　２０６・・・復号化制御部
　３００，４００，５００，６００・・・ループフィルタ処理部
　３０１，４０１・・・ブロック分割部
　３０２，４０２・・・フィルタ切り替え部
　３０３，４０３，５０３，６０３・・・フィルタ処理部
　３０４，４０４・・・ブロック統合部
　５１０，６１０・・・フィルタ適用切り替え部
　１０００，３０００・・・動画像符号化部
　２０００，４０００・・・動画像復号化部 DESCRIPTION OF SYMBOLS 10 ... Input image signal 11 ... Predictive image signal 12 ... Prediction error signal 13 ... Quantization transform coefficient 14 ... Encoded data 15 ... Prediction error signal 16 ... Locally decoded image Signal 17 ... Reference image signal 21 ... Decoded image signal 31 ... Filter number information 32 ... Filter information 33 ... Block division information 34 ... Filter specific information 35 ... Local decoded pixel block 36 ... Reconstructed pixel block 41 ... Decoded pixel block 51 ... Filter application information 101 ... Prediction signal generator 102 ... Subtractor 103 ... Transformer / Quantizer 104 ... Entropy code Conversion unit 105 ... Inverse transformation / inverse quantization unit 106 ... Adder 107 ... Reference image buffer 108 ... Encoding control unit 201 ... Entropy decoding unit 20 ... Inverse transformation / inverse quantization unit 203 ... Adder 204 ... Prediction signal generation unit 205 ... Reference image buffer 206 ... Decoding control unit 300,400,500,600 ... Loop Filter processing unit 301, 401 ... Block division unit 302, 402 ... Filter switching unit 303, 403, 503, 603 ... Filter processing unit 304, 404 ... Block integration unit 510, 610 ... Filter Application switching unit 1000, 3000 ... moving image encoding unit 2000, 4000 ... moving image decoding unit

Claims (10)

  1. 　符号化済みの画像に関する参照画像を利用して予測画像を生成する動画像符号化方法において、
    　符号化単位の局所復号画像を複数のブロックに分割するためのパラメータを含むブロック分割情報を設定することと、
    　前記符号化単位のためのフィルタ群の各フィルタのフィルタ係数を含むフィルタ情報を設定することと、
    　前記フィルタ群に含まれるフィルタの数を示すフィルタ数情報を設定することと、
    　前記ブロック毎に適用すべきフィルタを特定するフィルタ特定情報を設定することと、
    　前記ブロック毎に前記フィルタ特定情報によって特定されるフィルタを適用し、前記参照画像を生成することと、
    　前記フィルタ数情報、前記フィルタ情報、前記ブロック分割情報及び前記フィルタ特定情報を符号化することと
    　を具備する動画像符号化方法。     In a moving image encoding method for generating a predicted image using a reference image related to an encoded image,
    Setting block division information including parameters for dividing a locally decoded image of a coding unit into a plurality of blocks;
    Setting filter information including filter coefficients of each filter of the filter group for the coding unit;
    Setting filter number information indicating the number of filters included in the filter group;
    Setting filter specifying information for specifying a filter to be applied for each block;
    Applying a filter specified by the filter specifying information for each block, and generating the reference image;
    A video encoding method comprising: encoding the filter number information, the filter information, the block division information, and the filter specifying information.
  2. 　前記ブロックを更に分割したサブブロック毎のフィルタの適用／非適用を示すフィルタ適用情報を設定することと、
    　前記フィルタ適用情報を符号化することと
    　を更に具備する請求項１記載の動画像符号化方法。     Setting filter application information indicating application / non-application of a filter for each sub-block obtained by further dividing the block;
    The moving image encoding method according to claim 1, further comprising encoding the filter application information.
  3. 　前記符号化単位は、フレームまたはスライスである請求項２記載の動画像符号化方法。 3. The moving picture coding method according to claim 2, wherein the coding unit is a frame or a slice.
  4. 　前記フィルタ特定情報は、前記フィルタ群に含まれるフィルタのうちの１つを特定するインデックスであって、
    　前記インデックスは、所定の可変長テーブルに従って符号化され、
    　前記所定の可変長テーブルは、所定のタイミングで切り替えられる
    　請求項３記載の動画像符号化方法     The filter specifying information is an index for specifying one of the filters included in the filter group,
    The index is encoded according to a predetermined variable length table,
    The moving image encoding method according to claim 3, wherein the predetermined variable length table is switched at a predetermined timing.
  5. 　前記フィルタ情報は、フィルタのタップ長、フィルタの形状、前記フィルタ係数の対称性及び前記フィルタ係数の量子化ビット精度のうち少なくとも１つを示す情報を更に含む
    　請求項４記載の動画像符号化方法。     The moving picture encoding method according to claim 4, wherein the filter information further includes information indicating at least one of a filter tap length, a filter shape, symmetry of the filter coefficient, and quantization bit precision of the filter coefficient. .
  6. 　復号化済みの画像に関する参照画像を利用して予測画像を生成する動画像復号化方法において、
    　復号化単位の復号画像を複数のブロックに分割するためのパラメータを含むブロック分割情報を復号化することと、
    　前記復号化単位のためのフィルタ群に含まれるフィルタの数を示すフィルタ数情報を復号化することと、
    　前記フィルタ群の各フィルタのフィルタ係数を含むフィルタ情報を復号化することと、
    　前記ブロック毎に適用すべきフィルタを特定するフィルタ特定情報を復号化することと、
    　前記ブロック毎に前記フィルタ特定情報によって特定されるフィルタを適用し、前記参照画像を生成することと
    　を具備する動画像復号化方法。     In a video decoding method for generating a predicted image using a reference image related to a decoded image,
    Decoding block division information including parameters for dividing a decoded image of a decoding unit into a plurality of blocks;
    Decoding filter number information indicating the number of filters included in the filter group for the decoding unit;
    Decoding filter information including filter coefficients of each filter of the filter group;
    Decoding filter specifying information for specifying a filter to be applied for each block;
    Applying a filter specified by the filter specifying information for each block and generating the reference image. A moving picture decoding method comprising:
  7. 　前記ブロックを更に分割したサブブロック毎のフィルタの適用／非適用を示すフィルタ適用情報を復号化することを更に具備する請求項６記載の動画像復号化方法。 The moving picture decoding method according to claim 6, further comprising decoding filter application information indicating application / non-application of a filter for each sub-block obtained by further dividing the block.
  8. 　前記復号化単位は、フレームまたはスライスである請求項７記載の動画像復号化方法。 The moving picture decoding method according to claim 7, wherein the decoding unit is a frame or a slice.
  9. 　前記フィルタ特定情報は、前記フィルタ群に含まれるフィルタのうちの１つを特定するインデックスであって、
    　前記インデックスは、所定の可変長テーブルに従って復号化され、
    　前記所定の可変長テーブルは、所定のタイミングで切り替えられる
    　請求項８記載の動画像復号化方法。     The filter specifying information is an index for specifying one of the filters included in the filter group,
    The index is decoded according to a predetermined variable length table,
    The moving image decoding method according to claim 8, wherein the predetermined variable length table is switched at a predetermined timing.
  10. 　前記フィルタ情報は、フィルタのタップ長、フィルタの形状、前記フィルタ係数の対称性及び前記フィルタ係数の量子化ビット精度のうち少なくとも１つを示す情報を更に含む請求項９記載の動画像復号化方法。 The moving picture decoding method according to claim 9, wherein the filter information further includes information indicating at least one of a filter tap length, a filter shape, symmetry of the filter coefficient, and quantization bit precision of the filter coefficient. .
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