WO2013065262A1 - Video encoding device, video decoding device, video encoding method, video decoding method, and program - Google Patents

Video encoding device, video decoding device, video encoding method, video decoding method, and program Download PDF

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WO2013065262A1
WO2013065262A1 PCT/JP2012/006847 JP2012006847W WO2013065262A1 WO 2013065262 A1 WO2013065262 A1 WO 2013065262A1 JP 2012006847 W JP2012006847 W JP 2012006847W WO 2013065262 A1 WO2013065262 A1 WO 2013065262A1
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level
video
block
encoding
decoding
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Japanese (ja)
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慶一 蝶野
啓史 青木
裕三 仙田
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日本電気株式会社
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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
    • H04N19/90—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals
    • H04N19/91—Entropy coding, e.g. variable length coding [VLC] or arithmetic coding
    • 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
    • H04N19/70—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards

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  • the present invention relates to a video encoding device and a video decoding device that perform entropy encoding based on Context-based Adaptive Variable Length Coding (CAVLC).
  • CAVLC Context-based Adaptive Variable Length Coding
  • run is the number of insignificant level that continues in the decoding order (the number of level ⁇ that has a value of 0 that continues in the decoding order).
  • level is a quantized value of the residual transform coefficient of the block.
  • the significant level is a level ⁇ ⁇ ⁇ whose value is not “0”.
  • the encoder transmits last_pos_level_one syntax indicating the position of the last significant level ⁇ in the block and its value (level value) is 1, and further transmits level_and_sign syntax indicating the absolute value of the significant level ⁇ and its positive / negative sign To do.
  • the last significant level ⁇ in the block is the first significant level ⁇ in the decoding order in the video decoding device (decoder).
  • the encoder transmits a run_level_one ⁇ ⁇ ⁇ ⁇ ⁇ syntax indicating a set of values of run and level ⁇ and a level_and_sign syntax as long as a predetermined condition is satisfied.
  • the predetermined condition is a condition that satisfies the following requirement (1) or (2) at the time when an untransmitted level ⁇ exists in the block and the level_and_sign syntax is transmitted immediately before.
  • the level value transmitted immediately before is 1 (2)
  • the level value transmitted immediately before is 2 or more, the block size is not 4 ⁇ 4, the number of untransmitted levels is less than the threshold switchThres, and the sum of the two or more level values already transmitted in the block is 2 or less
  • the level value is an absolute value.
  • a state in which run_level_one syntax and level_and_sign syntax are transmitted is referred to as a run mode.
  • Level mode a state in which the level syntax and the sign syntax are transmitted.
  • Non-Patent Document 1 describes a level mode (decoding process of level “syntax”).
  • a variable length code index vlcIdx having a value from 0 to 4 is used. That is, five types of variable length codes are used for decoding the level syntax.
  • a variable-length code of level syntax has a feature that the code length for a small level ⁇ ⁇ value is longer and the code length for a large level ⁇ ⁇ value is shorter as the value of vlcIdx is larger.
  • the initial value of vlcIdx used for level syntax decoding is 0.
  • LevelThreshold when a level syntax larger than the current vlcIdx level threshold LevelThreshold is decoded, the value of vlcIdx is incremented by one.
  • the value of the level threshold value is described in Table ⁇ 9-13 Derivation of levelThreshold from vlcIdx of Non-Patent Document 1.
  • the level threshold is designed so that the larger the value of vlcIdx is, the greater the value of the level threshold, in consideration of the characteristics of the variable-length code of level syntax.
  • FIG. 11 is an explanatory diagram of the number of level values included in the bit pattern prefetched by the decoder.
  • the level value is “1, ⁇ 1, 0, 0, 0, ⁇ 1, ⁇ 2, 1”, as shown in the lower part of FIG. , “010,011,1,1,1,011,0011,010”.
  • the variable length code of level value “0” is “1”.
  • the last bit is a positive / negative sign bit, “0” represents negative, and “1” represents positive. Therefore, a general encoder transmits a bit string of “010, 011, 1, 1, 1, 011, 0011, 010”.
  • the mechanism for prefetching bit patterns is configured in 8-bit units.
  • an 8-bit register is used.
  • “01001111” of the above bit string is first prefetched as shown in the lower part of FIG. In that case, the number of level ⁇ ⁇ ⁇ prefetched is four.
  • the encoder alternately transmits an absolute value of level ⁇ and a positive / negative sign of significant level. Therefore, the number of level included in the bit pattern prefetched by the variable length decoder is reduced by the number of positive and negative sign bits. As a result, since it is necessary to increase the number of prefetches, there is a problem that the throughput of the video decoding device is reduced.
  • an object of the present invention is to provide a video encoding device, a video decoding device, a video encoding method, a video decoding method, a video encoding program, and a video decoding program that can improve the throughput of the video decoding device.
  • the video encoding apparatus is a video encoding apparatus that uses context adaptive variable length encoding, and separately encodes an absolute value sequence of level ⁇ and a positive and negative code sequence of significant level ⁇ for each block.
  • Level mode encoding means is provided.
  • a video decoding device is a video decoding device using context adaptive variable length coding, in which an absolute value sequence of level and a significant level ⁇ positive and negative code sequence are separately encoded in blocks.
  • Level mode decoding means for decoding the level ⁇ in the block from the digitized data the level mode decoding means includes storage means for storing a sequence of absolute values of level ⁇ in the block, and in the block stored in the storage means The level ⁇ in the block is decoded from the absolute value sequence of the level ⁇ and the positive / negative code sequence.
  • the video encoding method according to the present invention is a video encoding method using context-adaptive variable-length encoding, and separately encodes a sequence of absolute values of level ⁇ and a positive and negative code sequence of significant levels ⁇ for each block. It is characterized by that.
  • the video decoding method according to the present invention is a video decoding method using context-adaptive variable-length coding, in which an absolute value sequence of level and a significant level ⁇ positive / negative code sequence are separately encoded in blocks. It is characterized by decoding the level in the block from the digitized data.
  • the video encoding program according to the present invention separately encodes an absolute value sequence of level ⁇ and a positive and negative code sequence of significant level ⁇ in units of blocks on a computer that performs video encoding processing using context-adaptive variable-length encoding. It is characterized in that the processing to be converted is executed.
  • an absolute value sequence of level ⁇ and a significant level ⁇ positive / negative code sequence are separately encoded in a block unit on a computer that performs video decoding processing using context-adaptive variable-length encoding.
  • a process for decoding each level in the block from the encoded data is performed.
  • the number of level ⁇ ⁇ included in the bit pattern prefetched by the variable length decoder is increased by the number of positive and negative code bits, and the number of level ⁇ ⁇ ⁇ that can be decoded by one variable length decoding process is increased. As a result, the throughput of the video decoding device is improved.
  • syntax It is explanatory drawing of the list
  • FIG. 1 is a block diagram illustrating a configuration of a video encoding device according to the first embodiment. 1 includes a predictor 101, a frequency converter 102, a quantizer 103, a variable length encoder 104, an inverse quantization / inverse frequency converter 105, and a buffer 106. Composed.
  • the video encoding device frequency-converts the residual signal (residual block signal) obtained by subtracting the prediction signal (predicted block signal) generated by the predictor 101 ⁇ ⁇ from the input signal (input block signal) by the frequency converter 102 ⁇ ⁇ . To convert to residual frequency conversion coefficient. Further, the video encoding apparatus obtains a residual level by quantizing the residual frequency transform coefficient by the quantizer 103.
  • the residual level is simply referred to as level.
  • the video encoding apparatus For the prediction of the subsequent input signal, the video encoding apparatus performs a reconstructed residual signal (reconstructed residual block signal) by performing inverse quantization / inverse frequency conversion on level by the inverse quantization / inverse frequency converter 105. Get. Further, the prediction signal is added and stored in the buffer 106 as a reconstructed signal (reconstructed block signal). The video encoding apparatus performs variable length encoding of level by the variable length encoder 104 and outputs a bit stream (encoded data).
  • FIG. 2 is a block diagram showing a configuration example of the level mode encoding unit 1040 in the variable length encoder 104.
  • the level mode encoding unit 1040 shown in FIG. 2 includes a non-zero level value counter 1042, a non-zero level value code buffer 1043, an absolute value extractor 1044, a variable length encoding unit 1045, and a switch 1046.
  • the non-zero level value counter 1042 sequentially inputs level ⁇ and counts the number of level ⁇ ⁇ ⁇ (significant level) that are not “0”.
  • the absolute value extractor 1044 sequentially inputs level and extracts the absolute value.
  • the absolute value extractor 1044 supplies the extracted absolute value to the variable length encoding unit 1045.
  • the variable length coding unit 1045 performs variable length coding on the absolute value of the level value.
  • the non-zero level value code buffer 1043 sequentially inputs level and stores the sign of significant level.
  • the switch 1046 selects either the output of the variable length encoding unit 1045 or the output of the non-zero level value code buffer 1043.
  • FIG. 3 is an explanatory diagram showing an example of an output bit stream of the level mode encoding unit 1040.
  • the level mode encoding unit 1040 of this embodiment transmits a bit string of “01, 01, 1, 1, 1, 01, 001, 01, 01110” as shown in the lower part of FIG.
  • step S101 the absolute value extractor 1044 extracts the absolute value of the input level value and supplies it to the variable length encoding unit 1045.
  • variable length encoding unit 1045 sequentially performs variable length encoding on the absolute value of the level threshold value extracted by the absolute value extractor 1044 in step S102.
  • the level value is “1, ⁇ 1, 0, 0, 0, ⁇ 1, ⁇ 2, 1”
  • the variable length coding unit 1045 uses a variable length coded data sequence corresponding to a predetermined number of blocks. “01011101” is output.
  • step S103 the non-zero level value counter 1042 counts the number of significant level values from the input level value for each predetermined number of blocks.
  • the non-zero level value code buffer 1043 stores data corresponding to data obtained by fixed-length encoding a significant level positive and negative code string with a bit length of the number of significant levels counted by the non-zero level value counter 1042.
  • the switch 1046 selects and outputs the variable-length encoded data sequence encoded by the variable-length encoding unit 1045 in step S105. Subsequently, in step S106, the switch 1046 selectively outputs a positive / negative code string stored in the non-zero level value code buffer 1043.
  • the level mode encoding unit 1040 can output the bitstream shown in the lower part of FIG.
  • the video encoding apparatus of the present embodiment first transmits a variable-length encoded data string of absolute values of level values excluding positive and negative codes, so that the number of level ⁇ ⁇ ⁇ that the video decoding device can prefetch at a time can be increased. it can.
  • the number of pre-fetched level is 4, whereas in this embodiment, the number of pre-fetched level is 5 (see FIG. 3).
  • the level value is encoded in a predetermined block unit, but the block unit is arbitrary.
  • the video encoding device includes the non-zero level value counter 1042, but includes a zero level value counter that counts the number of insignificant level values instead of the non-zero level value counter 1042. May be.
  • the level mode encoding unit 1040 separately encodes the absolute value sequence of the level value and the positive and negative code sequences of the significant level ⁇ value in a predetermined block unit.
  • the video decoding apparatus performs variable-length decoding on the absolute value sequence of level values in units of a predetermined number of blocks, and then decodes positive and negative fixed-length codes corresponding to the number of significant level values. Therefore, when compared with a general device, the expected value of the number of Level values that can be decoded by a single variable length decoding process increases in the video decoding device.
  • the Residual coding CAVLC syntax syntax is signaled as shown in List 1 shown in FIGS. 5A and 5B according to 7.3.11 Residual coding CAVLC syntax of Non-Patent Document 1.
  • elements represented by italic characters are elements different from 7.3.11 Residual coding CAVLC syntax of Non-Patent Document 1.
  • FIG. FIG. 6 is a block diagram illustrating a configuration of a video decoding apparatus corresponding to the video encoding apparatus of the first embodiment.
  • the video decoding apparatus according to the present embodiment includes a variable length decoder 204, an inverse quantization / inverse frequency converter 205, a predictor 201, and a buffer 202.
  • the variable length decoder 204 performs variable length decoding of the bit stream (encoded data) to obtain level.
  • the inverse quantization / inverse frequency converter 205 performs inverse quantization / inverse frequency conversion on level and outputs a reconstructed residual signal.
  • the reconstructed residual signal is added with the prediction signal supplied from the predictor 201 and stored in the buffer 202 as a reconstructed signal.
  • FIG. 7 is a block diagram showing a configuration example of the level mode decoding unit 2040 in the variable length decoder 204.
  • the level mode decoding unit 2040 illustrated in FIG. 7 includes a switch 2046, a variable length decoding unit 2045, a non-zero level value counter 2042, a non-zero level value code buffer 2043, a buffer 2047, and a code correction unit 2048.
  • level mode decoding unit 2040 The operation of the level mode decoding unit 2040 will be described with reference to the flowchart of FIG.
  • step S201 the switch 2046 selects either the absolute value sequence of the level value or the positive / negative code sequence of the significant level ⁇ ⁇ included in the encoding block based on the transmitted syntax.
  • step S202 the variable length decoding unit 2045 inputs a sequence of variable length encoded data having an absolute value of the level value, and decodes the absolute value of the level value.
  • the variable length decoding unit 2045 temporarily stores the decoded absolute values of the level values in a buffer 2047 as storage means.
  • the non-zero level value counter 2042 counts the number of significant level values decoded by the variable length decoding unit 2045.
  • the non-zero level value code buffer 2043 temporarily stores positive and negative code strings in step S203.
  • step S204 the sign correction unit 2048 restores the level value by adding a positive or negative sign to the absolute value of the significant level value.
  • the sign correction unit 2048 inputs an absolute value string of level values from the buffer 2047. Further, when there is a portion where “1” continues in the column, the positive and negative codes stored in the non-zero level value code buffer 2043 are read. Then, the code correction unit 2048 inserts the code at the position indicated by the count value of the non-zero level value counter 2042 in the code string stored in the non-zero level value code buffer 2043 between successive “1” s. At that time, the count value of the non-zero level value counter 2042 is decremented. In other words, the non-zero level value code buffer 2043 stores encoded data in which a positive / negative code string of significant level is fixed-length encoded with the number of bit levels of significant level.
  • the level mode decoding unit 2040 can restore the level value illustrated in the upper part of FIG. 3 when the bit stream illustrated in the lower part of FIG. 3 is input.
  • the video decoding device of this embodiment is used, interoperability with the video encoding device of the first embodiment can be improved. That is, the video encoding device and the video decoding device can work together to improve the throughput of the video decoding device.
  • the Residual coding CAVLC syntax shown in FIGS. 5A and 5B uses all the levels coded in the Level coding mode in the frequency conversion block as a block unit.
  • not all level ⁇ encoded in the Level mode in the frequency conversion block are set in units of blocks, for example, 16 levels May be a block unit.
  • the Residual coding CAVLC syntax of such an embodiment is shown in list 2 of FIGS. 9A, 9B, and 9C.
  • elements represented by italic characters are elements different from 7.3.11 Residual coding CAVLC syntax of Non-Patent Document 1.
  • all level ⁇ (n level) encoded in the Level mode in the frequency transform block are encoded using 16 levels as a block unit.
  • the size of the buffer 2047 of the video decoding apparatus shown in FIG. 7 can be restricted to 16 without impairing the encoding efficiency. That is, an increase in hardware cost of the video decoding device can be suppressed without impairing the encoding efficiency.
  • the information processing system illustrated in FIG. 10 includes a processor 1001, a program memory 1002, a storage medium 1003 for storing video data, and a storage medium 1004 for storing a bitstream.
  • the storage medium 1003 and the storage medium 1004 may be separate storage media, or may be storage areas composed of the same storage medium.
  • a magnetic storage medium such as a hard disk can be used as the storage medium.
  • the program memory 1002 stores a program for realizing the function of each block shown in FIGS. Then, the processor 1001 executes processing according to the program stored in the program memory 1002, thereby performing the video encoding device (level mode encoding unit 1040 shown in FIG. 2) shown in each of FIGS. And a video decoding device (including the level mode decoding unit 2040 shown in FIG. 7).

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Abstract

This video encoding device uses context-adaptive variable-length encoding and is provided with a level-mode encoding unit that, for each block, encodes the following separately: a sequence consisting of the absolute values of levels for said block; and a sequence consisting of encoded signs for significant levels. This video decoding device uses context-adaptive variable-length encoding and is provided with a level-mode decoding unit that decodes block levels from encoded data in which, for each block, a sequence consisting of the absolute values of the levels for said block and a sequence consisting of encoded signs for significant levels are encoded separately.

Description

映像符号化装置、映像復号装置、映像符号化方法、映像復号方法およびプログラムVideo encoding apparatus, video decoding apparatus, video encoding method, video decoding method, and program
　本発明は、Context-based Adaptive Variable Length Coding（CAVLC）に基づくエントロピー符号化を行う映像符号化装置および映像復号装置に関する。 The present invention relates to a video encoding device and a video decoding device that perform entropy encoding based on Context-based Adaptive Variable Length Coding (CAVLC).
　非特許文献１の7.3.11 Residual coding CAVLC syntax には、ブロックの残差情報であるrun およびlevel のシンタクスが記載されている。run は、解読順で連続する有意でないlevel の個数（解読順で連続する０の値のlevel の個数）である。level は、ブロックの残差変換係数の量子化値である。なお、有意level は、値が“０”でないlevel である。 Non-Patent Document 1 section 7.3.11 “Residual coding” CAVLC “syntax” describes the syntax of “run” and “level” that are residual information of blocks. run is the number of insignificant level that continues in the decoding order (the number of level の that has a value of 0 that continues in the decoding order). level is a quantized value of the residual transform coefficient of the block. The significant level is a level で な い whose value is not “0”.
　エンコーダは、ブロック内の最後の有意level の位置とその値（level 値）が１であるかを示すlast_pos_level_oneシンタクスを伝送し、さらに、有意level の絶対値とその正負の符号を示すlevel_and_signシンタクスを伝送する。ただし、ブロック内の最後の有意level は、映像復号装置（デコーダ）においては解読順で最初の有意level である。 The encoder transmits last_pos_level_one syntax indicating the position of the last significant level 内 in the block and its value (level value) is 1, and further transmits level_and_sign syntax indicating the absolute value of the significant level と and its positive / negative sign To do. However, the last significant level 内 in the block is the first significant level で in the decoding order in the video decoding device (decoder).
　続いて、エンコーダは、所定の条件を満たす限り、run とlevel の値との組を示すrun_level_one シンタクス、および、level_and_signシンタクスを伝送する。所定の条件は、未伝送のlevel がブロック内に存在し、かつ、直前にlevel_and_signシンタクスを伝送した時点で以下の（１）または（２）の要件を満たす条件である。 Subsequently, the encoder transmits a run_level_one エ ン コ ー ダ syntax indicating a set of values of run and level 組 and a level_and_sign syntax as long as a predetermined condition is satisfied. The predetermined condition is a condition that satisfies the following requirement (1) or (2) at the time when an untransmitted level 存在 exists in the block and the level_and_sign syntax is transmitted immediately before.
（１）直前に伝送したlevel 値が１
（２）直前に伝送したlevel 値が２以上、ブロックのサイズが４×４ではない、未伝送のlevel の個数が閾値switchThres 以下、および、ブロック内で伝送済みの２以上のlevel 値の合計が２以下 (1) The level value transmitted immediately before is 1
(2) The level value transmitted immediately before is 2 or more, the block size is not 4 × 4, the number of untransmitted levels is less than the threshold switchThres, and the sum of the two or more level values already transmitted in the block is 2 or less
ただし、上記（１）および（２）の要件において、level 値は絶対値であるとする。以下、run_level_one シンタクスとlevel_and_signシンタクスを伝送する状態をランモード（Run mode）と呼ぶ。 However, in the requirements (1) and (2) above, the level value is an absolute value. Hereinafter, a state in which run_level_one syntax and level_and_sign syntax are transmitted is referred to as a run mode.
　ランモード後に未伝送のlevel が存在する場合、エンコーダは、未伝送のlevel が存在する限り、level 値の絶対値を示すlevel シンタクスを伝送し、かつ、有意level であればその正負の符号を示すsignシンタクスを伝送する。以下、level シンタクスおよびsignシンタクスを伝送する状態をレベルモード（Level mode）と呼ぶ。 If there is an untransmitted level 後 に after the run mode, the encoder transmits a level syntax indicating the absolute value of the level value as long as there is an untransmitted level 、. Transmit sign syntax. Hereinafter, a state in which the level syntax and the sign syntax are transmitted is referred to as a level mode (Level mode).
　なお、ランモードおよびレベルモードに関する上記の“伝送”を“解読”に置き換えると、デコーダの動作が説明される。 It should be noted that the operation of the decoder is explained by replacing the above “transmission” regarding the run mode and the level mode with “decoding”.
　さらに、非特許文献１の9.2.4.4 Parsing process for level には、レベルモード（level シンタクスの解読プロセス）が記載されている。level シンタクスの解読には、０から４の値をとる可変長符号インデックスvlcIdxが用いられる。つまり、level シンタクスの解読には、５種類の可変長符号が用いられる。 Furthermore, 9.2.4.4 “Parsing process” for “level” of Non-Patent Document 1 describes a level mode (decoding process of level “syntax”). For decoding the level イ ン デ ッ ク ス syntax, a variable length code index vlcIdx having a value from 0 to 4 is used. That is, five types of variable length codes are used for decoding the level syntax.
　vlcIdx=0の可変長符号は、非特許文献１の9.2.1 Parsing Process for VLC codesに記載されている、vlcNum=0の可変長符号である。同様に、vlcIdx=1,2,3および4 の可変長符号は、それぞれ、vlcNum=1,2,3および4 の可変長符号である。level シンタクスの可変長符号は、vlcIdxの値が大きくなるほど、小さなlevel 値に対する符号長が長く、かつ、大きなlevel 値に対する符号長が短くなる特徴がある。 The variable length code of vlcIdx = 0 is a variable length code of vlcNum = 0 described in 9.2.1 Parsing Process for VLC codes of Non-Patent Document 1. Similarly, the variable length codes of vlcIdx = 1, 2, 3, and 4 are the variable length codes of vlcNum = 1, 2, 3, and 4 そ れ ぞ れ, respectively. A variable-length code of level syntax has a feature that the code length for a small level 長 く value is longer and the code length for a large level ほ ど value is shorter as the value of vlcIdx is larger.
　level シンタクス解読に用いるvlcIdxの初期値は０である。level シンタクス解読は、現在のvlcIdxレベル閾値LevelThresholdよりも大きなlevel シンタクスを復号したとき、vlcIdxの値を１インクリメントする。レベル閾値の値は、非特許文献１のTable 9-13 Derivation of levelThreshold from vlcIdx に記載されている。level シンタクスの可変長符号の特徴を考慮して、レベル閾値は、vlcIdxの値が大きいほど、その値が大きくなるように設計されている。 The initial value of vlcIdx used for level syntax decoding is 0. In the level syntax decoding, when a level syntax larger than the current vlcIdx level threshold LevelThreshold is decoded, the value of vlcIdx is incremented by one. The value of the level threshold value is described in Table 文献 9-13 Derivation of levelThreshold from vlcIdx of Non-Patent Document 1. The level threshold is designed so that the larger the value of vlcIdx is, the greater the value of the level threshold, in consideration of the characteristics of the variable-length code of level syntax.
　図１１は、デコーダがプリフェッチするビットパターンに含まれるlevel 値の個数の説明図である。図１１における上段に示すように、level 値が、“１，－１，０，０，０，－１，－２，１”である場合、図１１における下段に示すように、可変長符号は、“０１０，０１１，１，１，１，０１１，００１１，０１０”であるとする。level 値“０”の可変長符号は“１”である。2bit以上の符号において、最終ビットは正負の符号ビットであり、“０”は負を表し、“１”は正を表す。よって、一般的なエンコーダは、“０１０，０１１，１，１，１，０１１，００１１，０１０”のビット列を伝送する。 FIG. 11 is an explanatory diagram of the number of level values included in the bit pattern prefetched by the decoder. As shown in the upper part of FIG. 11, when the level value is “1, −1, 0, 0, 0, −1, −2, 1”, as shown in the lower part of FIG. , “010,011,1,1,1,011,0011,010”. The variable length code of level value “0” is “1”. In a code of 2 bits or more, the last bit is a positive / negative sign bit, “0” represents negative, and “1” represents positive. Therefore, a general encoder transmits a bit string of “010, 011, 1, 1, 1, 011, 0011, 010”.
　エンコーダにおいて、ビットパターンをプリフェッチする機構は、8bit単位で構成される。例えば、8bitレジスタが用いられる。8bitレジスタが用いられる場合には、図１１における下段に示すように、上記のビット列のうち、“０１００１１１１”が、まず、プリフェッチされる。その場合、プリフェッチされるlevel の個数は４である。 In the encoder, the mechanism for prefetching bit patterns is configured in 8-bit units. For example, an 8-bit register is used. When an 8-bit register is used, “01001111” of the above bit string is first prefetched as shown in the lower part of FIG. In that case, the number of level さ れ る prefetched is four.
　非特許文献１に記載されたレベルモードにおいて、エンコーダは、level の絶対値と有意level の正負の符号を交互に伝送する。ゆえに、正負の符号ビット分だけ、可変長復号器がプリフェッチするビットパターンに含まれるlevel の個数が減る。その結果、プリフェッチ回数を増やす必要があるので、映像復号装置のスループットが低下するという課題がある。 In the level mode described in Non-Patent Document 1, the encoder alternately transmits an absolute value of level と and a positive / negative sign of significant level. Therefore, the number of level included in the bit pattern prefetched by the variable length decoder is reduced by the number of positive and negative sign bits. As a result, since it is necessary to increase the number of prefetches, there is a problem that the throughput of the video decoding device is reduced.
　そこで、本発明は、映像復号装置のスループットを向上させることができる映像符号化装置、映像復号装置、映像符号化方法、映像復号方法、映像符号化プログラム、および映像復号プログラムを提供することを目的とする。 Accordingly, an object of the present invention is to provide a video encoding device, a video decoding device, a video encoding method, a video decoding method, a video encoding program, and a video decoding program that can improve the throughput of the video decoding device. And
　本発明による映像符号化装置は、コンテキスト適応型可変長符号化を用いる映像符号化装置であって、ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列を別々に符号化するレベルモード符号化手段を備えることを特徴とする。 The video encoding apparatus according to the present invention is a video encoding apparatus that uses context adaptive variable length encoding, and separately encodes an absolute value sequence of level と and a positive and negative code sequence of significant level で for each block. Level mode encoding means is provided.
　本発明による映像復号装置は、コンテキスト適応型可変長符号化を用いる映像復号装置であって、ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列が別々に符号化された符号化データから、ブロック内のlevel を復号するレベルモード復号手段を備え、レベルモード復号手段は、ブロック内のlevel の絶対値の列を格納する格納手段を含み、当該格納手段に格納されたブロック内のlevel の絶対値の列と正負の符号列とからブロック内のlevel を復号することを特徴とする。 A video decoding device according to the present invention is a video decoding device using context adaptive variable length coding, in which an absolute value sequence of level and a significant level 正 positive and negative code sequence are separately encoded in blocks. Level mode decoding means for decoding the level の in the block from the digitized data, the level mode decoding means includes storage means for storing a sequence of absolute values of level 内 in the block, and in the block stored in the storage means The level の in the block is decoded from the absolute value sequence of the level の and the positive / negative code sequence.
　本発明による映像符号化方法は、コンテキスト適応型可変長符号化を用いる映像符号化方法であって、ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列を別々に符号化することを特徴とする。 The video encoding method according to the present invention is a video encoding method using context-adaptive variable-length encoding, and separately encodes a sequence of absolute values of level と and a positive and negative code sequence of significant levels で for each block. It is characterized by that.
　本発明による映像復号方法は、コンテキスト適応型可変長符号化を用いる映像復号方法であって、ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列が別々に符号化された符号化データから、ブロック内のlevel を復号することを特徴とする。 The video decoding method according to the present invention is a video decoding method using context-adaptive variable-length coding, in which an absolute value sequence of level and a significant level 正 positive / negative code sequence are separately encoded in blocks. It is characterized by decoding the level in the block from the digitized data.
　本発明による映像符号化プログラムは、コンテキスト適応型可変長符号化を用いて映像符号化処理を行うコンピュータに、ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列を別々に符号化する処理を実行させることを特徴とする。 The video encoding program according to the present invention separately encodes an absolute value sequence of level と and a positive and negative code sequence of significant level で in units of blocks on a computer that performs video encoding processing using context-adaptive variable-length encoding. It is characterized in that the processing to be converted is executed.
　本発明による映像復号プログラムは、コンテキスト適応型可変長符号化を用いて映像復号処理を行うコンピュータに、ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列が別々に符号化された符号化データから、ブロック内の各level を復号する処理を実行させることを特徴とする。 In the video decoding program according to the present invention, an absolute value sequence of level と and a significant level 正 positive / negative code sequence are separately encoded in a block unit on a computer that performs video decoding processing using context-adaptive variable-length encoding. A process for decoding each level in the block from the encoded data is performed.
　本発明によれば、正負の符号ビットの分だけ、可変長復号器がプリフェッチするビットパターンに含まれるlevel の個数が増加し、一度の可変長復号処理によって復号できるlevel の個数が増加する。その結果、映像復号装置のスループットが向上する。 According to the present invention, the number of level 含 ま included in the bit pattern prefetched by the variable length decoder is increased by the number of positive and negative code bits, and the number of level で き る that can be decoded by one variable length decoding process is increased. As a result, the throughput of the video decoding device is improved.
第１の実施形態の映像符号化装置を示すブロック図である。It is a block diagram which shows the video coding apparatus of 1st Embodiment. レベルモード符号化部を示すブロック図である。It is a block diagram which shows a level mode encoding part. レベルモード符号化部の出力ビットストリームの説明図である。It is explanatory drawing of the output bit stream of a level mode encoding part. レベルモード符号化部の動作を示すフローチャートである。It is a flowchart which shows operation | movement of a level mode encoding part. Residual coding CAVLC syntax シンタクスを表すリスト１の説明図である。It is explanatory drawing of the list | wrist 1 showing Residual <> coding | CAVLC | syntax | syntax. Residual coding CAVLC syntax シンタクスを表すリスト１の説明図である。It is explanatory drawing of the list | wrist 1 showing Residual <> coding | CAVLC | syntax | syntax. 第２の実施形態の映像復号装置を示すブロック図である。It is a block diagram which shows the video decoding apparatus of 2nd Embodiment. レベルモード復号部を示すブロック図である。It is a block diagram which shows a level mode decoding part. レベルモード復号部の動作を示すフローチャートである。It is a flowchart which shows operation | movement of a level mode decoding part. Residual coding CAVLC syntax シンタクスを表すリスト２の説明図である。It is explanatory drawing of the list | wrist 2 showing Residual (coding) CAVLC (syntax) syntax. Residual coding CAVLC syntax シンタクスを表すリスト２の説明図である。It is explanatory drawing of the list | wrist 2 showing Residual (coding) CAVLC (syntax) syntax. Residual coding CAVLC syntax シンタクスを表すリスト２の説明図である。It is explanatory drawing of the list | wrist 2 showing Residual (coding) CAVLC (syntax) syntax. 本発明による映像符号化装置および映像復号装置の機能を実現可能な情報処理システムの構成例を示すブロック図である。It is a block diagram which shows the structural example of the information processing system which can implement | achieve the function of the video coding apparatus and video decoding apparatus by this invention. デコーダがプリフェッチするビットパターンに含まれるlevel 値の個数の説明図である。It is explanatory drawing of the number of level values contained in the bit pattern which a decoder prefetches.
実施形態１．
　図１は、第１の実施形態の映像符号化装置の構成を示すブロック図である。図１に示す本実施形態の映像符号化装置は、予測器101 、周波数変換器102 、量子化器103 、可変長符号化器104 、逆量子化／逆周波数変換器105 、および、バッファ106 によって構成される。 Embodiment 1. FIG.
FIG. 1 is a block diagram illustrating a configuration of a video encoding device according to the first embodiment. 1 includes a predictor 101, a frequency converter 102, a quantizer 103, a variable length encoder 104, an inverse quantization / inverse frequency converter 105, and a buffer 106. Composed.
　映像符号化装置は、予測器101 が生成した予測信号（予測ブロック信号）を入力信号（入力ブロック信号）から減じた、残差信号（残差ブロック信号）を、周波数変換器102 によって周波数変換して残差周波数変換係数に変換する。さらに、映像符号化装置は、残差周波数変換係数を量子化器103 によって量子化して残差レベルを得る。以後、残差レベルを単純にlevel と呼ぶ。 The video encoding device frequency-converts the residual signal (residual block signal) obtained by subtracting the prediction signal (predicted block signal) generated by the predictor 101 か ら from the input signal (input block signal) by the frequency converter 102 周波 数. To convert to residual frequency conversion coefficient. Further, the video encoding apparatus obtains a residual level by quantizing the residual frequency transform coefficient by the quantizer 103. Hereinafter, the residual level is simply referred to as level.
　以後の入力信号の予測のために、映像符号化装置は、逆量子化／逆周波数変換器105 によってlevel を逆量子化／逆周波数変換して再構築残差信号（再構築残差ブロック信号）を得る。さらに、予測信号を加えて再構築信号（再構築ブロック信号）としてバッファ106 に格納する。映像符号化装置は、可変長符号化器104 によってlevel を可変長符号化してビットストリーム（符号化データ）を出力する。 For the prediction of the subsequent input signal, the video encoding apparatus performs a reconstructed residual signal (reconstructed residual block signal) by performing inverse quantization / inverse frequency conversion on level by the inverse quantization / inverse frequency converter 105. Get. Further, the prediction signal is added and stored in the buffer 106 as a reconstructed signal (reconstructed block signal). The video encoding apparatus performs variable length encoding of level by the variable length encoder 104 and outputs a bit stream (encoded data).
　図２は、可変長符号化器104 におけるレベルモード符号化部1040の構成例を示すブロック図である。図２に示すレベルモード符号化部1040は、非零レベル値カウンタ1042、非零レベル値符号バッファ1043、絶対値抽出器1044、可変長符号化部1045、およびスイッチ1046を備える。 FIG. 2 is a block diagram showing a configuration example of the level mode encoding unit 1040 in the variable length encoder 104. The level mode encoding unit 1040 shown in FIG. 2 includes a non-zero level value counter 1042, a non-zero level value code buffer 1043, an absolute value extractor 1044, a variable length encoding unit 1045, and a switch 1046.
　非零レベル値カウンタ1042は、level を順次入力し、“０”でないlevel （有意level ）の個数をカウントする。絶対値抽出器1044は、level を順次入力し、その絶対値を抽出する。絶対値抽出器1044は、抽出した絶対値を可変長符号化部1045に供給する。可変長符号化部1045は、level 値の絶対値を可変長符号化する。非零レベル値符号バッファ1043は、level を順次入力し、有意level の符号を記憶する。 The non-zero level value counter 1042 sequentially inputs level 、 and counts the number of level で な い (significant level) that are not “0”. The absolute value extractor 1044 sequentially inputs level and extracts the absolute value. The absolute value extractor 1044 supplies the extracted absolute value to the variable length encoding unit 1045. The variable length coding unit 1045 performs variable length coding on the absolute value of the level value. The non-zero level value code buffer 1043 sequentially inputs level and stores the sign of significant level.
　スイッチ1046は、可変長符号化部1045の出力と非零レベル値符号バッファ1043の出力のいずれかを選択する。 The switch 1046 selects either the output of the variable length encoding unit 1045 or the output of the non-zero level value code buffer 1043.
　図３は、レベルモード符号化部1040の出力ビットストリームの一例を示す説明図である。図３における上段に示すように、level 値が、“１，－１，０，０，０，－１，－２，１”である場合を例にする。本実施形態のレベルモード符号化部1040は、図３における下段に示すように、“０１，０１，１，１，１，０１，００１，０１，０１１１０”のビット列を伝送する。 FIG. 3 is an explanatory diagram showing an example of an output bit stream of the level mode encoding unit 1040. As shown in the upper part of FIG. 3, a case where the level value is “1, −1, 0, 0, 0, −1, −2, 1” is taken as an example. The level mode encoding unit 1040 of this embodiment transmits a bit string of “01, 01, 1, 1, 1, 01, 001, 01, 01110” as shown in the lower part of FIG.
　次に、レベルモード符号化部1040の動作を、図４のフローチャートを参照して説明する。 Next, the operation of the level mode encoding unit 1040 will be described with reference to the flowchart of FIG.
　絶対値抽出器1044は、ステップS101で、入力したlevel 値の絶対値を抽出し、可変長符号化部1045に供給する。 In step S101, the absolute value extractor 1044 extracts the absolute value of the input level value and supplies it to the variable length encoding unit 1045.
　可変長符号化部1045は、ステップS102で、絶対値抽出器1044によって抽出されたlevel 値の絶対値を順次可変長符号化する。level 値が“１，－１，０，０，０，－１，－２，１”である場合、可変長符号化部1045は、所定数のブロックに対応する可変長符号化データの列として“０１０１１１１０１”を出力する。 The variable length encoding unit 1045 sequentially performs variable length encoding on the absolute value of the level threshold value extracted by the absolute value extractor 1044 in step S102. When the level value is “1, −1, 0, 0, 0, −1, −2, 1”, the variable length coding unit 1045 uses a variable length coded data sequence corresponding to a predetermined number of blocks. “01011101” is output.
　非零レベル値カウンタ1042は、ステップS103で、予め決められている所定数のブロック毎に、入力したlevel 値から有意level の個数をカウントする。 In step S103, the non-zero level value counter 1042 counts the number of significant level values from the input level value for each predetermined number of blocks.
　非零レベル値符号バッファ1043は、ステップS104で、入力したlevel のうち、非零レベル値カウンタ1042がカウントした位置の有意level 値の正負の符号を順次記憶する。level 値が“１，－１，０，０，０，－１，－２，１”である場合、３番目、４番目、および５番目ののlevel は有意でないので、非零レベル値符号バッファ1043は、それら以外のlevel の正負の符号の集まり（符号列）である“０１１１０”（＝＋，－，－，－，＋）を記憶する。すなわち、非零レベル値符号バッファ1043は、非零レベル値カウンタ1042がカウントした有意なlevel の個数のビット長で有意なlevel の正負の符号列が固定長符号化されたデータに相当するデータを記憶する。 In step S104, the non-zero level value code buffer 1043 sequentially stores the positive and negative signs of the significant level value at the position counted by the non-zero level value counter 1042 among the input level values. If the level value is “1, -1, 0, 0, 0, −1, −2, 1”, the third, fourth, and fifth level values are not significant, so the non-zero level value code buffer 1043 stores “01110” (= +, −, −, −, +), which is a collection (code string) of other positive and negative signs of level 以外. That is, the non-zero level value code buffer 1043 stores data corresponding to data obtained by fixed-length encoding a significant level positive and negative code string with a bit length of the number of significant levels counted by the non-zero level value counter 1042. Remember.
　スイッチ1046は、ステップS105で、可変長符号化部1045が符号化した可変長符号化データの列を選択出力する。続けて、スイッチ1046は、ステップS106で、非零レベル値符号バッファ1043が記憶する正負の符号列を選択出力する。 The switch 1046 selects and outputs the variable-length encoded data sequence encoded by the variable-length encoding unit 1045 in step S105. Subsequently, in step S106, the switch 1046 selectively outputs a positive / negative code string stored in the non-zero level value code buffer 1043.
　以上のような処理によって、レベルモード符号化部1040は、図３における下段に示すビットストリームを出力することができる。 Through the above processing, the level mode encoding unit 1040 can output the bitstream shown in the lower part of FIG.
　本実施形態の映像符号化装置は、まず、正負の符号を除くlevel 値の絶対値の可変長符号化データの列を伝送するので、映像復号装置が一度にプリフェッチできるlevel の個数を増やすことができる。図１１に示す例では、プリフェッチされるlevel の個数は４であったのに対して、本実施形態では、プリフェッチされるlevel の個数は５である（図３参照）。 The video encoding apparatus of the present embodiment first transmits a variable-length encoded data string of absolute values of level values excluding positive and negative codes, so that the number of level で き る that the video decoding device can prefetch at a time can be increased. it can. In the example shown in FIG. 11, the number of pre-fetched level is 4, whereas in this embodiment, the number of pre-fetched level is 5 (see FIG. 3).
　なお、本実施形態では、所定のブロック単位でlevel 値が符号化されるが、ブロック単位は任意である。また、本実施形態では、映像符号化装置は、非零レベル値カウンタ1042を備えるが、非零レベル値カウンタ1042に代えて、有意でないlevel 値の個数をカウントする零レベル値カウンタが備えられていてもよい。 In this embodiment, the level value is encoded in a predetermined block unit, but the block unit is arbitrary. In the present embodiment, the video encoding device includes the non-zero level value counter 1042, but includes a zero level value counter that counts the number of insignificant level values instead of the non-zero level value counter 1042. May be.
　本実施形態では、レベルモード符号化部1040は、所定のブロック単位で、level 値の絶対値の列と有意level 値の正負の符号列とを別々に符号化する。後述するように、映像復号装置は、所定数のブロック単位で、level 値の絶対値の列を可変長復号した後に、有意level 値の個数の正負の固定長符号を復号する。よって、一般的な装置と比較した場合、映像復号装置において、一度の可変長復号処理によって復号できるLevel 値の個数の期待値が増加する。 In the present embodiment, the level mode encoding unit 1040 separately encodes the absolute value sequence of the level value and the positive and negative code sequences of the significant level で value in a predetermined block unit. As will be described later, the video decoding apparatus performs variable-length decoding on the absolute value sequence of level values in units of a predetermined number of blocks, and then decodes positive and negative fixed-length codes corresponding to the number of significant level values. Therefore, when compared with a general device, the expected value of the number of Level values that can be decoded by a single variable length decoding process increases in the video decoding device.
　なお、本実施形態において、Residual coding CAVLC syntaxシンタクスは、非特許文献１の7.3.11 Residual coding CAVLC syntax に従うと、図５Ａおよび図５Ｂに示すリスト１に表されるようにシグナリングされる。図５Ａおよび図５Ｂにおいて、斜体キャラクタで表される要素が、非特許文献１の7.3.11 Residual coding CAVLC syntax とは異なる要素である。 In this embodiment, the Residual coding CAVLC syntax syntax is signaled as shown in List 1 shown in FIGS. 5A and 5B according to 7.3.11 Residual coding CAVLC syntax of Non-Patent Document 1. In FIG. 5A and FIG. 5B, elements represented by italic characters are elements different from 7.3.11 Residual coding CAVLC syntax of Non-Patent Document 1.
　図５Ａおよび図５Ｂに示すように、まず、level 値の絶対値の列に関するシンタクス要素が伝送され、続いて、有意level 値の正負の符号列に関するシンタクス要素が伝送されることが分かる。 As shown in FIG. 5A and FIG. 5B, first, it is understood that the syntax elements related to the absolute value sequence of the level values are transmitted, and subsequently, the syntax elements related to the positive and negative code sequences of the significant level values are transmitted.
実施形態２．
　図６は、第１の実施形態の映像符号化装置に対応する、映像復号装置の構成を示すブロック図である。本実施形態の映像復号装置は、可変長復号器204 、逆量子化／逆周波数変換器205 、予測器201 、および、バッファ202 によって構成される。 Embodiment 2. FIG.
FIG. 6 is a block diagram illustrating a configuration of a video decoding apparatus corresponding to the video encoding apparatus of the first embodiment. The video decoding apparatus according to the present embodiment includes a variable length decoder 204, an inverse quantization / inverse frequency converter 205, a predictor 201, and a buffer 202.
　可変長復号器204 は、ビットストリーム（符号化データ）を可変長復号しlevel を得る。逆量子化／逆周波数変換器205 は、level を逆量子化／逆周波数変換して、再構築残差信号を出力する。再構築残差信号は、予測器201 から供給される予測信号が加えられて、再構築信号としてバッファ202 に格納される。 The variable length decoder 204 performs variable length decoding of the bit stream (encoded data) to obtain level. The inverse quantization / inverse frequency converter 205 performs inverse quantization / inverse frequency conversion on level and outputs a reconstructed residual signal. The reconstructed residual signal is added with the prediction signal supplied from the predictor 201 and stored in the buffer 202 as a reconstructed signal.
　図７は、可変長復号器204 におけるレベルモード復号部2040の構成例を示すブロック図である。図７に示すレベルモード復号部2040は、スイッチ2046、可変長復号部2045、非零レベル値カウンタ2042、非零レベル値符号バッファ2043、バッファ2047、および符号補正部2048を備える。 FIG. 7 is a block diagram showing a configuration example of the level mode decoding unit 2040 in the variable length decoder 204. The level mode decoding unit 2040 illustrated in FIG. 7 includes a switch 2046, a variable length decoding unit 2045, a non-zero level value counter 2042, a non-zero level value code buffer 2043, a buffer 2047, and a code correction unit 2048.
　レベルモード復号部2040の動作を、図８のフローチャートを参照して説明する。 The operation of the level mode decoding unit 2040 will be described with reference to the flowchart of FIG.
　スイッチ2046は、ステップS201で、伝送されたシンタクスに基づいて、符号化ブロックに含まれる、level 値の絶対値の列と有意level 値の正負の符号列のいずれかを選択する。 In step S201, the switch 2046 selects either the absolute value sequence of the level value or the positive / negative code sequence of the significant level 含 ま included in the encoding block based on the transmitted syntax.
　可変長復号部2045は、ステップS202で、level 値の絶対値の可変長符号化データの列を入力し、level 値の絶対値を復号する。可変長復号部2045は、復号した各々のlevel 値の絶対値を格納手段としてのバッファ2047に一時記憶する。 In step S202, the variable length decoding unit 2045 inputs a sequence of variable length encoded data having an absolute value of the level value, and decodes the absolute value of the level value. The variable length decoding unit 2045 temporarily stores the decoded absolute values of the level values in a buffer 2047 as storage means.
　非零レベル値カウンタ2042は、可変長復号部2045が復号した有意level 値の個数をカウントする。非零レベル値符号バッファ2043は、ステップS203で、正負の符号列を一時記憶する。 The non-zero level value counter 2042 counts the number of significant level values decoded by the variable length decoding unit 2045. The non-zero level value code buffer 2043 temporarily stores positive and negative code strings in step S203.
　符号補正部2048は、ステップS204で、有意level 値の絶対値に正負の符号を付加することによって、level 値を復元する。具体的には、符号補正部2048は、バッファ2047からlevel 値の絶対値の列を入力する。また、当該列中に“１”が連続する部分がある場合、非零レベル値符号バッファ2043に記憶されている正負の符号を読み出す。そして、符号補正部2048は、連続する“１”の間に、非零レベル値符号バッファ2043に記憶されている符号列において非零レベル値カウンタ2042のカウント値が示す位置の符号を挿入する。そのとき、非零レベル値カウンタ2042のカウント値は、デクリメントされる。すなわち、非零レベル値符号バッファ2043には、有意level の個数のビット長で有意なlevel の正負の符号列が固定長符号化された符号化データが記憶されていることになる。 In step S204, the sign correction unit 2048 restores the level value by adding a positive or negative sign to the absolute value of the significant level value. Specifically, the sign correction unit 2048 inputs an absolute value string of level values from the buffer 2047. Further, when there is a portion where “1” continues in the column, the positive and negative codes stored in the non-zero level value code buffer 2043 are read. Then, the code correction unit 2048 inserts the code at the position indicated by the count value of the non-zero level value counter 2042 in the code string stored in the non-zero level value code buffer 2043 between successive “1” s. At that time, the count value of the non-zero level value counter 2042 is decremented. In other words, the non-zero level value code buffer 2043 stores encoded data in which a positive / negative code string of significant level is fixed-length encoded with the number of bit levels of significant level.
　以上のような処理によって、レベルモード復号部2040は、図３における下段に例示すビットストリームを入力した場合、図３における上段に例示するlevel 値を復元できる。 Through the processing as described above, the level mode decoding unit 2040 can restore the level value illustrated in the upper part of FIG. 3 when the bit stream illustrated in the lower part of FIG. 3 is input.
　本実施形態の映像復号装置を用いると、第１の実施形態の映像符号化装置との相互運用性を高めることができる。すなわち、映像符号化装置と映像復号装置とが共動して、映像復号装置のスループットを向上させることができる。 If the video decoding device of this embodiment is used, interoperability with the video encoding device of the first embodiment can be improved. That is, the video encoding device and the video decoding device can work together to improve the throughput of the video decoding device.
　上記の各実施形態において、図５Ａおよび図５Ｂに示したResidual coding CAVLC syntaxシンタクスは、周波数変換ブロック内のLevel モードで符号化されるすべてのlevel をブロック単位とした。図７に示す映像復号装置のバッファ2047のサイズを小さくするために、例えば、周波数変換ブロック内のLevel モードで符号化されるすべてのlevel をブロック単位とするのではなく、例えば、16個のlevel をブロック単位としてもよい。 In each of the above-described embodiments, the Residual coding CAVLC syntax shown in FIGS. 5A and 5B uses all the levels coded in the Level coding mode in the frequency conversion block as a block unit. In order to reduce the size of the buffer 2047 of the video decoding apparatus shown in FIG. 7, for example, not all level 符号 encoded in the Level mode in the frequency conversion block are set in units of blocks, for example, 16 levels May be a block unit.
　そのような実施形態のResidual coding CAVLC syntaxシンタクスを、図９Ａ、図９Ｂ、および図９Ｃのリスト２に示す。図９Ａ、図９Ｂ、および図９Ｃにおいて、斜体キャラクタで表される要素が、非特許文献１の7.3.11 Residual coding CAVLC syntax とは異なる要素である。図９Ａ、図９Ｂ、および図９Ｃにおいては、周波数変換ブロック内のLevel モードで符号化されるすべてのlevel （n 個のlevel ）を、16個のlevelをブロック単位として符号化する。そのような実施形態では、符号化効率を損なうことなく、図７に示す映像復号装置のバッファ2047のサイズを16に制約できる。つまり、符号化効率を損なうことなく映像復号装置のハードウェアコスト増加を抑制できる。 The Residual coding CAVLC syntax of such an embodiment is shown in list 2 of FIGS. 9A, 9B, and 9C. In FIG. 9A, FIG. 9B, and FIG. 9C, elements represented by italic characters are elements different from 7.3.11 Residual coding CAVLC syntax of Non-Patent Document 1. In FIG. 9A, FIG. 9B, and FIG. 9C, all level 符号 (n level) encoded in the Level mode in the frequency transform block are encoded using 16 levels as a block unit. In such an embodiment, the size of the buffer 2047 of the video decoding apparatus shown in FIG. 7 can be restricted to 16 without impairing the encoding efficiency. That is, an increase in hardware cost of the video decoding device can be suppressed without impairing the encoding efficiency.
　なお、上記の各実施形態を、ハードウェアで構成することも可能であるが、コンピュータプログラムにより実現することも可能である。 Note that each of the above embodiments can be configured by hardware, but can also be realized by a computer program.
　図１０に示す情報処理システムは、プロセッサ１００１、プログラムメモリ１００２、映像データを格納するための記憶媒体１００３およびビットストリームを格納するための記憶媒体１００４を備える。記憶媒体１００３と記憶媒体１００４とは、別個の記憶媒体であってもよいし、同一の記憶媒体からなる記憶領域であってもよい。記憶媒体として、ハードディスク等の磁気記憶媒体を用いることができる。 The information processing system illustrated in FIG. 10 includes a processor 1001, a program memory 1002, a storage medium 1003 for storing video data, and a storage medium 1004 for storing a bitstream. The storage medium 1003 and the storage medium 1004 may be separate storage media, or may be storage areas composed of the same storage medium. A magnetic storage medium such as a hard disk can be used as the storage medium.
　図１０に示された情報処理システムにおいて、プログラムメモリ１００２には、図１，図６のそれぞれに示された各ブロックの機能を実現するためのプログラムが格納される。そして、プロセッサ１００１は、プログラムメモリ１００２に格納されているプログラムに従って処理を実行することによって、図１，図６のそれぞれに示された映像符号化装置（図２に示すレベルモード符号化部1040を含む。）または映像復号装置（図７に示すレベルモード復号部2040を含む。）の機能を実現する。 In the information processing system shown in FIG. 10, the program memory 1002 stores a program for realizing the function of each block shown in FIGS. Then, the processor 1001 executes processing according to the program stored in the program memory 1002, thereby performing the video encoding device (level mode encoding unit 1040 shown in FIG. 2) shown in each of FIGS. And a video decoding device (including the level mode decoding unit 2040 shown in FIG. 7).
　以上、実施形態および実施例を参照して本願発明を説明したが、本願発明は上記実施形態および実施例に限定されるものではない。本願発明の構成や詳細には、本願発明のスコープ内で当業者が理解し得る様々な変更をすることができる。 As mentioned above, although this invention was demonstrated with reference to embodiment and an Example, this invention is not limited to the said embodiment and Example. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
　この出願は、２０１１年１１月４日に出願された日本特許出願２０１１－２４２１８３を基礎とする優先権を主張し、その開示の全てをここに取り込む。 This application claims priority based on Japanese Patent Application No. 2011-242183 filed on November 4, 2011, the entire disclosure of which is incorporated herein.
　101 　予測器
　102 　周波数変換器
　103 　量子化器
　104 　可変長符号化器
　105 　逆量子化／逆周波数変換器
　106 　バッファ
　201 　予測器
　202 　バッファ
　204 　可変長復号器
　205 　逆量子化／逆周波数変換器
　1040　レベルモード符号化部
　1042　非零レベル値カウンタ
　1043　非零レベル値符号バッファ
　1044　絶対値抽出器
　1045　可変長符号化部
　1046　スイッチ
　2040　レベルモード復号部
　2042　非零レベル値カウンタ
　2043　非零レベル値符号バッファ
　2045　可変長復号部
　2046　スイッチ
　2047　バッファ
　2048　符号補正部 101 Predictor 102 Frequency converter 103 Quantizer 104 Variable length encoder 105 Inverse quantization / inverse frequency converter 106 Buffer 201 Predictor 202 Buffer 204 Variable length decoder 205 Inverse quantization / Inverse frequency converter 1040 Level mode Encoder 1042 Non-zero level value counter 1043 Non-zero level value code buffer 1044 Absolute value extractor 1045 Variable length encoder 1046 Switch 2040 Level mode decoder 2042 Non-zero level value counter 2043 Non-zero level value code buffer 2045 Variable length Decoding unit 2046 Switch 2047 Buffer 2048 Code correction unit

Claims (8)

  1. 　コンテキスト適応型可変長符号化を用いる映像符号化装置であって、
    　ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列を別々に符号化するレベルモード符号化手段を備えることを特徴とする映像符号化装置。     A video encoding apparatus using context adaptive variable length encoding,
    A video encoding apparatus comprising level mode encoding means for separately encoding an absolute value sequence of level and a positive and negative code sequence of significant level in block units.
  2. 　前記レベルモード符号化手段は、ブロック内の有意なlevel の個数をカウントするカウント手段を含み、当該カウント手段がカウントした前記有意なlevel の個数のビット長で前記有意なlevel の正負の符号列を固定長符号化する
    　請求項１記載の映像符号化装置。     The level mode encoding means includes counting means for counting the number of significant levels in the block, and the sign level of the significant level with a bit length of the number of significant levels counted by the counting means. The video encoding device according to claim 1, wherein fixed-length encoding is performed.
  3. 　コンテキスト適応型可変長符号化を用いる映像復号装置であって、
    　ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列が別々に符号化された符号化データから、ブロック内のlevel を復号するレベルモード復号手段を備え、
    　前記レベルモード復号手段は、ブロック内のlevel の絶対値の列を格納する格納手段を含み、当該格納手段に格納されたブロック内のlevel の絶対値の列と前記正負の符号列とからブロック内のlevel を復号することを特徴とする映像復号装置。     A video decoding apparatus using context adaptive variable length coding,
    Level mode decoding means for decoding the level in the block from encoded data in which the absolute value sequence of level and the positive and negative code sequences of significant level are encoded separately in block units,
    The level mode decoding means includes storage means for storing a sequence of level absolute values in the block, and the level mode decoding means includes a level absolute value sequence in the block and the positive / negative code sequence stored in the block. A video decoding device that decodes the level of the video.
  4. 　前記レベルモード復号手段は、復号した有意level の個数をカウントするカウント手段を含み、当該カウント手段のカウント値が示す個数の正負の符号を前記格納手段に格納されているlevel の絶対値の列に挿入することによってlevel を復号する
    　請求項３記載の映像復号装置。     The level mode decoding means includes counting means for counting the number of significant levels that have been decoded, and the number of positive and negative signs indicated by the count value of the counting means is stored in an absolute value column of level stored in the storage means. The video decoding device according to claim 3, wherein level is decoded by inserting the level.
  5. 　コンテキスト適応型可変長符号化を用いる映像符号化方法であって、
    　ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列を別々に符号化することを特徴とする映像符号化方法。     A video coding method using context adaptive variable length coding,
    A video encoding method, wherein a sequence of absolute values of level and a positive / negative code sequence of significant levels are encoded separately in block units.
  6. 　コンテキスト適応型可変長符号化を用いる映像復号方法であって、
    　ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列が別々に符号化された符号化データから、ブロック内のlevel を復号することを特徴とする映像復号方法。     A video decoding method using context adaptive variable length coding, comprising:
    A video decoding method comprising: decoding a level in a block from encoded data obtained by separately encoding an absolute value sequence of level and a positive and negative code sequence of significant level in block units.
  7. 　コンテキスト適応型可変長符号化を用いて映像符号化処理を行うコンピュータに、
    　ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列を別々に符号化する処理を実行させるための映像符号化プログラム。     To a computer that performs video coding processing using context-adaptive variable-length coding,
    A video encoding program for executing processing to separately encode absolute value sequences of level and positive and negative code sequences of significant levels in block units.
  8. 　コンテキスト適応型可変長符号化を用いて映像復号処理を行うコンピュータに、
    　ブロック単位でlevel の絶対値の列と有意なlevel の正負の符号列が別々に符号化された符号化データから、ブロック内の各level を復号する処理を実行させるための映像復号プログラム。     To a computer that performs video decoding processing using context-adaptive variable-length coding,
    A video decoding program for executing a process of decoding each level in a block from encoded data in which a sequence of absolute values of levels and positive and negative code sequences of significant levels are encoded separately in block units.
PCT/JP2012/006847 2011-11-04 2012-10-25 Video encoding device, video decoding device, video encoding method, video decoding method, and program WO2013065262A1 (en)

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