Source: http://patents.com/us-9591311.html
Timestamp: 2017-04-29 23:28:42
Document Index: 121598

Matched Legal Cases: ['Application No. 12802482', 'Application No. 12804632', 'Application No. 12803936', 'Application No. 12804513', 'Application No. 12802462', 'Application No. 12811252', 'Application No. 2012277214', 'Application No. 2013152611', 'Application No. 201280025496', 'Application No. 2012277219', 'Application No. 1', 'Application No. 1']

US Patent # 9,591,311. Image decoding method, image coding method, image decoding apparatus,
image coding apparatus, and image coding and decoding apparatus - Patents.com
United States Patent 9,591,311
Image decoding method, image coding method, image decoding apparatus,
image coding apparatus, and image coding and decoding apparatus
The image coding method includes: determining a context for a current
block to be processed, from among a plurality of contexts; and performing
arithmetic coding on the control parameter for the current block to
generate a bitstream corresponding to the current block, wherein in the
determining: the context is determined under a condition that control
parameters of neighboring blocks of the current block are used, when the
signal type is a first type, the neighboring blocks being a left block
and an upper block of the current block; and the context is determined
under a condition that the control parameter of the upper block is not
used, when the signal type is a second type, and the second type is one
of "mvd_l0" and "mvd_l1".
Inventors: Sasai; Hisao (Osaka, JP), Nishi; Takahiro (Nara, JP), Shibahara; Youji (Tokyo, JP), Sugio; Toshiyasu (Osaka, JP), Tanikawa; Kyoko (Osaka, JP), Matsunobu; Toru (Osaka, JP) Applicant: Name City State Country Type Panasonic Intellectual Property Corporation of America Torrance CA US Assignee:
1000002445945
14/838,740
Prior Publication Data Document IdentifierPublication Date US 20150373336 A1Dec 24, 2015 Related U.S. Patent Documents Application NumberFiling DatePatent NumberIssue Date 14302777Jun 12, 20149154783 13533205Aug 19, 20148811762 61501390Jun 27, 2011 Current U.S. Class: 1/1 Current CPC Class: H04N 19/139 (20141101); H04N 19/105 (20141101); H04N 19/119 (20141101); H04N 19/13 (20141101); H04N 19/134 (20141101); H04N 19/176 (20141101); H04N 19/196 (20141101); H04N 19/463 (20141101); H04N 19/583 (20141101); H04N 19/593 (20141101); H04N 19/70 (20141101); H04N 19/12 (20141101); H04N 19/52 (20141101)
Current International Class: G06K 9/36 (20060101); H04N 19/176 (20140101); H04N 19/139 (20140101); H04N 19/119 (20140101); H04N 19/13 (20140101); H04N 19/134 (20140101); H04N 19/593 (20140101); H04N 19/463 (20140101); H04N 19/105 (20140101); H04N 19/70 (20140101); H04N 19/583 (20140101); H04N 19/196 (20140101); H04N 19/52 (20140101); H04N 19/12 (20140101)
Field of Search: ;382/232-233,238-240,247 ;375/240.02,240.12,240.13
Jahanghir et al.
7592937
7664180
7809060
7856060
7894523
7983343
8107533
8126056
8180201
8194747
8396344
8526492
8542977
Alessandrini et al.
8989265
9078003
9124891
9241162
2004/0008033
2004/0066974
2004/0151248
2004/0151252
2005/0013497
2005/0018768
2005/0053293
2005/0123207
2005/0152682
2005/0185928
2006/0088286
2006/0109149
2006/0120461
2006/0188012
2006/0204228
2006/0209949
2006/0215999
2006/0216000
2006/0233530
2006/0291556
2007/0041451
2007/0041452
2007/0160147
2007/0162852
2007/0183491
2007/0194953
2007/0200949
2007/0205927
2007/0223582
2007/0263723
2008/0025396
2008/0063060
2008/0063061
2008/0069231
2008/0069232
2008/0117988
2008/0118218
2008/0118224
2008/0123947
2008/0123977
2008/0130747
2008/0130988
2008/0130989
2008/0130990
2008/0131079
2008/0137744
2008/0137748
2008/0144715
2008/0158027
2008/0159641
2008/0165849
2008/0205522
2008/0219393
2009/0003441
2009/0034856
2009/0034857
2009/0103624
2009/0123066
2009/0141798
2009/0153378
2009/0168873
2009/0225861
2009/0225862
2009/0232205
2009/0304075
2010/0014589
2010/0020873
2010/0020876
2010/0040140
2010/0080285
2010/0098155
2010/0183079
2010/0183080
2010/0202539
2010/0238998
2010/0239002
2010/0266048
2010/0315270
2011/0019739
2011/0080464
2011/0095922
2011/0102210
2011/0102213
2011/0113451
2011/0115656
2011/0129016
2011/0135143
2011/0148674
2011/0150075
2011/0206125
2011/0249721
2012/0044099
2012/0189058
2012/0224639
2012/0230411
2012/0275523
2012/0287997
2012/0288008
2012/0288009
2012/0288010
2012/0288011
2012/0294354
2012/0328024
2013/0003858
2013/0010862
2013/0010874
2013/0010875
2013/0051452
2013/0058399
2013/0064300
2013/0070850
2013/0107945
2013/0107967
2013/0177079
2013/0188741
2013/0308704
2013/0329784
2014/0003495
2014/0064375
2014/0064376
2014/0072046
2014/0072047
2014/0153649
2014/0341277
2015/0110188
2015/0131736
2015/0172701
2015/0195536
2015/0264349
2015/0264350
2015/0271518
101390385
101600104
101626244
102077244
2 015 581
2 182 732
2 330 325
200306618
I324338
I327030
I328357
I329843
I330976
2004/086758
2006/006936
2010/021699
2010/125606
Other References International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004046. cited by applicant
.International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004047. cited by applicant
.International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004051. cited by applicant
.International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004060. cited by applicant
.International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004063. cited by applicant
.International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004067. cited by applicant
.International Search Report issued Oct. 2, 2012 in International Application No. PCT/JP2012/004407. cited by applicant
.Detlev Marpe et al., "Context-Based Adaptive Binary Arithmetic Coding in the H.264/AVC Video Compression Standard", IEEE Transactions on Circuits and Systems for Video Technology, vol. 13, No. 7, Jul. 2003. cited by applicant
.Thomas Wiegand et al., "WD2: Working Draft 2 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D503, 4th Meeting: Daegu, KR, Jan. 20-28, 2011. cited by applicant
.Frank Bossen, "Common Test Conditions and Software Reference Configurations", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E700, 4th Meeting,: Daegu, KR, Jan. 20-28, 2011. cited by applicant
.Gisle Bjontegaard, "Improvements of the BD-PSNR Model", ITU-T SG16/Q6 Document, VCEG-AI11, 35th Meeting: Berlin, Germany, Jul. 16-18, 2008. cited by applicant
.Thomas Wiegand et al., "WD3: Working Draft 3 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E603, ver.7, 5th Meeting: Geneva, CH, Mar. 16-23, 2011,
http://phenix.int-evry.fr/jct/doc.sub.--end.sub.--user/documents/5.sub.--- Geneva/wg11/JCTVCE-603-v7.zip. cited by applicant
.Thomas Wiegand, "Joint Final Committee Draft (JFCD) of Joint Video Specification (ITU-T Rec. H.264 | ISO/IEC 14496-10 AVC)", Joint Video Team (JVT) of ISO/IEC MPEG and ITU-T VCEG 4.sup.th Meeting: Klagenfurt, Austria, Jul. 22-26, 2002, [JVT-D157].
.Vivienne Sze, Anantha P. Chandrakasan, "Joint Algorithm-Architecture Optimization of CABAC", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11 5.sup.th Meeting: Geneva, CH, Mar. 16-23, 2011, [JCTVC-E324].
.Xiaoyin Che et al., "Enhanced Context Modeling for Skip and Split Flag", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11 4th Meeting: Daegu, KR, Jan. 20-28, 2011, [JCTVC-D254]. cited by applicant
.Thomas Wiegand et al., "WD3: Working Draft 3 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E603, Ver. 8, 5th Meeting: Geneva, CH, Mar. 16-23, 2011. cited by
.International Search Report issued Sep. 25, 2012 in International Application No. PCT/JP2012/004061. cited by applicant
.International Search Report issued Sep. 25, 2012 in corresponding International Application No. PCT/JP2012/004068. cited by applicant
.Hisao Sasai et al., "Modified Context Derivation for Complexity reduction", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F429] (Version 1). cited by
.Jianle Chen et al., "Simplified context model selection for block level syntax coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F497] (Version
1). cited by applicant
.Thomas Wiegand et al., "WD3: Working Draft 3 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11 5th Meeting: Geneva, CH, Mar. 16-23, 2011, May 1, 2011 (Version 3),
<JCTVC-E603.sub.--d3.doc>. cited by applicant
.Extended European Search Report dated Oct. 22, 2014 for the European Patent Application No. 12802482.5. cited by applicant
.Thomas Wiegand et al., "WD3: Working Draft 3 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E603, 5th Meeting: Geneva, CH, Mar. 16-23, 2011. cited by applicant
.Ken McCann,"HM3: High Efficiency Video Coding (HEVC) Test Model 3 Encoder Description", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E602, 5th Meeting: Geneva, CH, Mar. 16-23, 2011. cited by
.Wei-Jung Chen et al.,"CE5: Improved coding of inter prediction mode with LCEC", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D370, 4th Meeting: Daegu, KR, Jan. 20-28, 2011. cited by applicant
.Virginie Drugeon, "Improvement of inter mode coding and split flags coding for LCEC", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E258, 5th Meeting: Geneva, CH, Mar. 16-23, 2011. cited by
.Bin Li, "Adaptive coding order for skip and split flags in LCEC", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D140, 4th Meeting: Daegu, KR, Jan. 20-28, 2011. cited by applicant
.Toshiyasu Sugio et al., "Parsing Robustness for Merge/AMVP", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F470]. cited by applicant
.Extended European Search Report dated Nov. 4, 2014 for the European Patent Application No. 12804632.3. cited by applicant
.Jian Lou et al., "On context selection for significant.sub.--coeff.sub.--flag coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 5th Meeting: Geneva, CH, Mar. 16-23, 2011, Document: JCTVC-E362,
XP030008868. cited by applicant
.Vivienne Sze et al., "Reduced neighboring dependency in context selection of significant.sub.--coeff.sub.--flag for parallel processing", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 5th Meeting:
Geneva, CH, Mar. 16-23, 2011, Document: JCTVC-E330, XP030008836. cited by applicant
.Vivienne Sze et al., "Joint Algorithm-Architecture Optimization of Cabac to Increase Speed and Reduce Area Cost", Acoustics, Speech and Signal Processing (ICASSP), 2011 IEEE International Conference, May 22, 2011, pp. 1577-1580, XP032001128. cited
."Text of Final Committee Draft of Joint Video Specification (ITU-T Rec. H.264 | ISO/IEC 14496-10 AVC)", International Organisation for Standardisation, Jul. 2002, XP030012343. cited by applicant
.Extended European Search Report dated Nov. 4, 2014 for the European Patent Application No. 12803936.9. cited by applicant
.Extended European Search Report dated Nov. 4, 2014 for the European Patent Application No. 12804513.5. cited by applicant
.Thomas Wiegand et al., "WD3: Working Draft 3 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-E603, 5th Meeting: Geneva, CH, Mar. 16-23, 2011, XP055146641. cited
.Vivienne Sze, "CE11: Simplified context selection for significant.sub.--coeff.sub.--flag (JCTVC-C227)", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D195, 4th Meeting: Daegu, KR, Jan. 20-28,
2011, XP030008235. cited by applicant
.Gary Sullivan, "Meeting report of the fifth meeting of the Joint Collaborative Team on Video Coding (JCT-VC), Geneva, CH, Mar. 16-23, 2011", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11,
JCTVC-E.sub.--Notes.sub.--d6, 5th Meeting: Geneva, CH, Mar. 16-23, 2011, XP030009012. cited by applicant
.Thomas Wiegand et al., "WD2: Working Draft 2 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D503, 4th Meeting: Daegu, KR, Jan. 20-28, 2011, XP030113315. cited
.Thomas Wiegand, "Joint Final Committee Draft (JFCD) of Joint Video Specification (ITU-T Rec. H.264 | ISO/IEC 14496-10 AVC)", Joint Video Team (JVT) of ISO/IEC MPEG and ITU-T VCEG, JVT-D157, 4th Meeting: Klagenfurt, Austria; Jul. 22-26, 2002,
XP030005420. cited by applicant
.Hisao Sasai, "Modified MVD coding for CABAC", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F423], XP030049414. cited by applicant
.Vivienne Sze, "Simplified MVD context selection (Extension of E324)", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F133], XP030009156. cited by
.Vivienne Sze, "BoG report on context reduction for CABAC", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F746], XP030009769. cited by applicant
.Extended European Search Report dated Nov. 4, 2014 for the European Patent Application No. 12802462.7. cited by applicant
.Wei-Jung Chien et al., "Memory and Parsing Friendly CABAC Context", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F606]. cited by applicant
.Extended European Search Report dated Dec. 12, 2014 for the European Patent Application No. 12811252.1. cited by applicant
.Che et al., "Enhanced Context Modeling for Skip and Split Flag", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D254, Jan. 2011, pp. 1-4, [JCTVC-D254 Version 1]. cited by applicant
.Office Action issued Sep. 17, 2015 in U.S. Appl. No. 13/544,061. cited by applicant
.Wei-Jung Chien et al., "Memory and Parsing Friendly CABAC Context", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11; 6th Meeting: Torino, IT; Jul. 20, 2011, [JCTVC-F606] (version 3). cited by applicant
.Cheung Auyeung, "Parallel processing friendly simplified context selection of significance map", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, JCTVC-D260, 4th Meeting: Daegu, KR, Jan. 20-28, 2011,
XP030008300. cited by applicant
.Benjamin Bross et al., "WD4: Working Draft 4 of High-Efficiency Video Coding", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11; 6th Meeting: Torino, IT, Oct. 28, 2011, [JCTVC-F803.sub.--d5] (version 7),
pp. 189-192. cited by applicant
.Notice of Acceptance issued May 5, 2016 in corresponding Australian Patent Application No. 2012277214. cited by applicant
.Office Action dated Aug. 15, 2016 in Malaysian Patent Application No. PI 2013702238. cited by applicant
.Decision on Granting dated Sep. 14, 2016 in Russian Patent Application No. 2013152611 (with English translation). cited by applicant
.Office Action mailed on Jul. 14, 2016 for the corresponding Chinese Patent Application No. 201280025496.7 (with English translation of Search Report). cited by applicant
.Wei-Jung Chien et al., "Memory and Parsing Friendly CABAC Context", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F606.sub.--r1]. cited by applicant
.Hisao Sasai, Takahiro Nishi, "Modified Context Derivation for Complexity reduction", Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 6th Meeting: Torino, IT, Jul. 14-22, 2011, [JCTVC-F429.sub.--r1].
.Official Communication of EP 12803936.9 issued Jun. 23, 2016. cited by applicant
.Official Communication of EP 12804513.5 issued Jun. 23, 2016. cited by applicant
.Office Action dated Jul. 1, 2016 in Australian Patent Application No. 2012277219. cited by applicant
.Office Action dated Jul. 21, 2016 in U.S. Appl. No. 13/535,414. cited by applicant
.Office Action dated Aug. 9, 2016 in Philippines Patent Application No. 1-2013-502458. cited by applicant
.Office Action dated Oct. 11, 2016 in Philippines Patent Application No. 1-2013-502502. cited by applicant
.Office Action dated Dec. 1, 2016 in U.S. Appl. No. 13/535,414. cited by applicant. Primary Examiner: Patel; Kanjibhai
This is a continuation of application Ser. No. 14/302,777, filed Jun. 12,
2014, now U.S. Pat. No. 9,154,783, which is a continuation of application
Ser. No. 13/533,205, filed Jun. 26, 2012, now U.S. Pat. No. 8,811,762,
61/501,390 filed on Jun. 27, 2011. The entire disclosures of the
Claims The invention claimed is: 1. A coding and decoding apparatus for coding a first control parameter for controlling coding of a first image and decoding a second control parameter for controlling
decoding of a second image, the coding and decoding apparatus comprising: processing circuitry; and a memory, wherein the processing circuitry performs the following: determining a first context for a first current block in the first image, from among a
plurality of first contexts stored in the memory; and performing arithmetic coding on the first control parameter for the first current block to generate a first bitstream, using the determined first context, wherein the determining of a first context
includes: determining a first signal type under which the first control parameter for the first current block is classified; determining the first context by using both of coded first control parameters for a first left block and a first upper block,
when the first signal type is a first type, the first left block being a neighboring block to the left of the first current block, and the first upper block being a neighboring block on top of the first current block; and determining the first context
by using a predetermined first fixed value, without using any of the coded first control parameters for the first left block and the first upper block, when the first signal type is a second type different from the first type, wherein the first control
parameter determined as the first type belongs to the first current block having a size larger than or equal to a size of a first block to which the first control parameter determined as the second type belongs, wherein one of a first split flag and a
first skip flag is classified under the first type, the first split flag indicating whether or not the first current block is partitioned into a plurality of blocks, and the first skip flag indicating whether or not the first current block is to be
skipped, wherein a first difference parameter is classified under the second type, the first difference parameter indicating a difference between a first motion vector and a first motion vector predictor of the first current block, wherein the processing
circuitry further performs the following: determining a second context for a second current block in the second image, from among a plurality of second contexts stored in the memory; and performing arithmetic decoding on a second bitstream corresponding
to the second current block, using the determined second context to obtain the second control parameter for the second current block, wherein the determining of a second context includes: determining a second signal type under which the second control
parameter for the second current block is classified; determining the second context by using both of decoded second control parameters for a second left block and a second upper block, when the second signal type is a third type, the second left block
being a neighboring block to the left of the second current block, and the second upper block being a neighboring block on top of the second current block; and determining the second context by using a predetermined second fixed value, without using any
of the decoded second control parameters for the second left block and the second upper block, when the second signal type is a fourth type different from the third type, wherein the second control parameter determined as the third type belongs to the
second current block having a size larger than or equal to a size of a second block to which the second control parameter determined as the fourth type belongs, wherein one of a second split flag and a second skip flag is classified under the third type,
the second split flag indicating whether or not the second current block is partitioned into a plurality of blocks, and the second skip flag indicating whether or not the second current block is to be skipped, and wherein a second difference parameter is
classified under the fourth type, the second difference parameter indicating a difference between a second motion vector and a second motion vector predictor of the second current block. Description TECHNICAL FIELD
The present invention relates to an image decoding method, an image coding method, an image decoding apparatus, an image coding apparatus, and an image coding and decoding apparatus, and in particular to an image decoding method, an image coding
method, an image decoding apparatus, an image coding apparatus, and an image coding and decoding apparatus which use arithmetic coding or arithmetic decoding.
Natural image signals have statistical variations showing nonstationary behavior. One of the entropy coding methods using the nonstationary statistical variations is Context-Based Adaptive Binary Arithmetic Coding (CABAC) (see NPL 1). CABAC is
employed as the ITU-T/ISOIEC standard for video coding, H.264/AVC.
(1) "Context-Based Adaptive" means adapting the coding and decoding methods to the statistical variations. In other words, "Context-Based Adaptive" means predicting an appropriate probability as an occurrence probability of a symbol along with
an event of surrounding conditions, when the symbol is coded or decoded. In coding, when an occurrence probability p(x) of each value of a symbol S is determined, a conditional occurrence probability is applied using an actual event or a sequence of
events F(z) as a condition.
(2) "Binary" means representation of a symbol using a binary sequence. A symbol represented by a multi-value is once mapped to a binary sequence referred to as "bin string". A predicted probability (conditional probability) is switched and
used for each of the sequence elements, and occurrence of one of the events of the two values is represented by a bit sequence. Accordingly, the probability of a value can be managed (initialized and updated) using a unit (binary element unit) smaller
than a unit of a signal type (see FIG. 2 and others of NPL 1).
(3) "Arithmetic" means that the bit sequence is generated not with reference to the correspondences in a table but by the computation. In the coding scheme using the tables of variable-length codes such as H.263, MPEG-4, and H.264, even each
value of a symbol with an occurrence probability greater than 0.5 (50%) needs to be associated with one binary sequence (bit sequence). Thus, a value with the greatest probability needs to be associated with one bit for one symbol at minimum. In
contrast, the arithmetic coding can represent the occurrence of an event with a higher probability by an integer equal to or smaller than one bit. When (i) there is a signal type in which the occurrence probability of having the first binary value as 0
exceeds 0.9 (90%) and (ii) an event having the first binary value as 0 successively occurs N times, there is no need to output data of 1 bit N times for each value of "0".
[NPL 1] Detlev Marpe, et. al., "Context-Based Adaptive Binary Arithmetic Coding in the H.264/AVC Video Compression Standard", IEEE Transaction on circuits and systems for video technology, Vol. 13, No. 7, July 2003. [NPL 2] Joint Collaborative
Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 4th Meeting: Daegu, KR, 20-28 Jan. 2011 "WD2: Working Draft 2 of High-Efficiency Video Coding" JCTVC-D503 http://wftp3.itu.int/av-arch/jctvc-site/2011_01_D_Daegu/JCTVC-D503.doc
[NPL 3] Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG16 WP3 and ISO/IEC JTC1/SC29/WG11, 4th Meeting: Daegu, KR, 20-28 Jan. 2011, "Common test conditions and software reference configurations", JCTVC-E700 [NPL 4] Gisle Bjontegaard,
"Improvements of the BD-PSNR model," ITU-T SG16 Q.6 Document, VCEG-AI11, Berlin, July 2008
In order to achieve the object, the image decoding method according to an aspect of the present invention is an image decoding method using arithmetic decoding, and the method includes: determining a context for use in a current block to be
processed, from among a plurality of contexts; performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context to reconstruct a binary sequence, the bit sequence being obtained by performing arithmetic
coding on a control parameter of the current block; and inversely binarizing the binary sequence to reconstruct the control parameter of the current block, wherein the determining of a context includes: determining a signal type of the control parameter
of the current block; determining the context under a first condition that decoded control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block
of the current block; and determining the context under a second condition that the decoded control parameter of the upper block is not used, when the signal type is a second type different from the first type, the first type is one of
"split_coding_unit_flag" and "skip_flag", and the second type is one of "mvd_l0" and "mvd_l1".
The present invention can provide an image coding method or an image decoding method that can reduce the memory usage. BRIEF DESCRIPTION OF DRAWINGS
These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings that illustrate a specific embodiment of the present invention. In
In High-Efficiency Video Coding (HEVC) that is a next-generation video coding scheme, the context model in coding and decoding various control parameters is being studied (NPL 2). The control parameter is included in a coded bitstream, and is a
parameter (flag, etc.) used in coding or decoding processing. More specifically, the control parameter is a syntax element.
The context model is information indicating (i) which condition is considered for (ii) a signal of which unit (each element of a multi-value, a binary value, a binary sequence (bin string). Here, "which condition" indicates which condition with
the number of conditional elements is applied or which signal type of a control parameter to be considered as a condition is appropriate. As the conditions are divided into smaller categories, that is, as the number of conditions .tau. increases, the
number of the cases that hold true for the conditions decreases. As a result, since the number of trainings decreases, the precision of the predicted probability decreases (for example, see "dilution effect" in NPL 1).
In designing a context model, after determining a guideline for designing the model, it is necessary to consider the validity of the model by conducting verifications specialized for an image, such as the verifications of statistical variations
in details of an image and in control parameter for controlling coding and decoding of an image.
The first context model uses coded values of up to two neighboring coded values (see NPL 1). Although the definition of the two neighboring coded values depends on each signal type, normally, values of corresponding control parameters included
in neighboring blocks to the left and upper of the current block are used.
The third and fourth types of context models relate to coding and decoding of residual values (residual data), such as image data. The third type uses only the past coded or decoded values in the scanning order of frequency coefficients (or
quantized coefficients). The fourth type determines a context according to the decoded and accumulated values (levels).
The advantages of the design principle and implementation of the probability transition model in H.264, such as the first type, have long been studied, and will be applied to HEVC that is being studied (see NPL 2). For example, the first type
(context model using neighboring syntax elements) is being studied to be used for the control parameters alf_cu_flag, split_coding_unit_flag, skip_flag, merge_flag, intra_chroma_pred_mode, inter_pred_flag, ref_idx_Ic, ref_idx_l0, ref_idx_l1, mvd_l0,
mvd_l1, mvd_lc, no_residual_data_flag, cbf_luma, cbf_cb, and cbf_cr (see 9.3.3.1.1 of NPL 2).
FIG. 17 illustrates context models using values of control parameters corresponding to the two neighboring blocks. Furthermore, FIG. 17 illustrates the context models using the neighboring blocks in H.264.
The block C in FIG. 17 includes a value of a control parameter SE currently to be coded and decoded. When the value of the control parameter SE is coded, values of control parameters SE of the same type included in the upper block A and the
left block B that are already coded are used. More specifically, the probability p(x) indicating whether the value x of the control parameter SE of the block C (or the first binary value of bin string of the control parameter SE) is 1 or 0 is predicted
based on a conditional probability p(x|(condition A (value of the upper block) and condition B (value of the left block)) using, as conditions, the value of the control parameter SE of the upper block A and the value of the control parameter SE of the
left block B.
In FIG. 18, (xP, yP) is a position of an upper left pixel of a prediction unit (PU, unit of motion prediction) including the block C. Here, the block C is a block including a control parameter (for example, skip_flag) currently to be coded. Furthermore, (xP, yA) in FIG. 18 is a position of a pixel that is included in the block B and is used as a condition A (value of the control parameter skip_flag of the upper block). Furthermore, (xL, yP) in FIG. 18 is a position of a pixel that is
included in the block A and is used as a condition B (value of the control parameter skip_flag of the left block).
In order to code or decode the value of the control parameter skip_flag of the block C, the coding apparatus or the decoding apparatus needs to hold the value of skip_flag of PU (or a result of determination of a condition) corresponding to the
position (xP, yA) included in the upper block B and the position (xL, yP) included in the left block A. Assuming that the picture has a horizontal width of 4096 pixels, in order to code one control parameter skip_flag, it is necessary to hold all the
determination values included in the upper row (Line L in FIG. 18). In other words, one control parameter needs the memory capacity obtained by 4096 pixels/block size.
Here, the block C to be coded has variable sizes, for example, 64.times.64, 16.times.16, or 4.times.4. Furthermore, the block size of the block C to be later coded or decoded cannot be predicted when the blocks in the upper row (Line L)
including (xP, yA) are coded or decoded. This is because the size of each of the blocks in the lower row (row including the block C) is not known when the upper row (row including the block A) is coded or decoded. Thus, the coding apparatus or the
decoding apparatus needs to hold a value of a control parameter (or determination value) for each minimum block size, assuming that the smallest block size from among all the sizes applied to the control parameters is used as the block size of the lower
row. The positions of the black circles in FIG. 18 indicate conditions that have to be held, although the conditional values are not actually necessary when the lower row (row including the block C) is coded and decoded.
Furthermore, the two neighboring blocks in FIG. 18 (the left block A and the upper block B) follow the concept of the neighboring blocks in H.264, and no new perspective on the division of hierarchical blocks is introduced. As described below,
there are cases where such conditional values to be referred to in FIG. 18 do not always make sense for control parameters adapted to the recursive quad tree partitioning to be introduced in HEVC, because the control parameters follow the recursive
execution order, the hierarchical depth, or positions of blocks.
As such, the present inventors have found that the memory usage increases by using the conditional values of the upper blocks in performing arithmetic coding or decoding on the control parameters. Furthermore, the present inventors have found
that the memory usage further increases in HEVC.
In contrast, the image decoding method according to an aspect of the present invention is an image decoding method using arithmetic decoding, and the method includes: determining a context for use in a current block to be processed, from among a
plurality of contexts; performing arithmetic decoding on a bit sequence corresponding to the current block, using the determined context to reconstruct a binary sequence, the bit sequence being obtained by performing arithmetic coding on a control
parameter of the current block; and inversely binarizing the binary sequence to reconstruct the control parameter of the current block, wherein the determining of a context includes: determining a signal type of the control parameter of the current
block; determining the context under a first condition that decoded control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current
block; and determining the context under a second condition that the decoded control parameter of the upper block is not used, when the signal type is a second type different from the first type, the first type is one of "split_coding_unit_flag" and
"skip_flag", and the second type is one of "mvd_l0" and "mvd_l1".
With the structure, the image decoding method can reduce the memory usage. More specifically, in the image decoding method, since the control parameter of the upper block is not used for a control parameter of the second type, there is no need
to hold the control parameter of the second type of the upper block. With the structure, compared to the case where the left block and the upper block are used as uniformly "using a context model based on values of control parameters of neighboring
blocks", the memory usage can be reduced according to the image decoding method. Furthermore, the image decoding method can appropriately reduce the memory usage of the control parameter of the second type without, for example, failing to evaluate a
BD-rate of an image.
Furthermore, the determining of a context may further include: determining whether or not the decoded control parameter of the upper block is available in decoding, based on a position of the current block; and determining the context under the
second condition, when the decoded control parameter of the upper block is not available.
Furthermore, in the determining of a context, it may be determined whether or not the decoded control parameter of the upper block is available in decoding, according to a hierarchical depth of a data unit to which the control parameter of the
current block belongs.
Furthermore, the determining of a context may further include determining a context of a control parameter of a second unit smaller than a first unit by switching between the first condition and the second condition, based on a control parameter
of the first unit.
Furthermore, the "split_coding_unit_flag" may indicate whether or not the current block is partitioned into a plurality of blocks, the "skip_flag" may indicate whether or not the current block is to be skipped, the "mvd_l0" may indicate a
difference between a motion vector component of a list 0 and a predicted value of the motion vector component, the motion vector component and the predicted value being used for the current block, the "mvd_l1" may indicate a difference between a motion
vector component of a list 1 and a predicted value of the motion vector component, the motion vector component and the predicted value being used for the current block, and "mvd_lc" may indicate a difference between a motion vector component of a list
combination and a predicted value of the motion vector component, the motion vector component and the predicted value being used for the current block.
Furthermore, decoding processes in accordance with a first standard and decoding processes in accordance with a second standard may be switched according to an identifier indicating one of the first standard and the second standard, the
identifier being included in a coded signal, and the determining of a context, the performing, and the inversely binarizing may be performed as the decoding processes in accordance with the first standard, when the identifier indicates the first
Furthermore, the image coding method according to an aspect of the present invention is an image coding method using arithmetic coding, and the method includes: binarizing a control parameter of a current block to be processed to generate a
binary sequence; determining a context for use in the current block, from among a plurality of contexts; and performing arithmetic coding on the binary sequence using the determined context to generate a bit sequence, wherein the determining of a context
includes: determining a signal type of the control parameter of the current block; determining the context under a first condition that control parameters of neighboring blocks of the current block are used, when the signal type is a first type, the
neighboring blocks being a left block and an upper block of the current block; and determining the context under a second condition that the control parameter of the upper block is not used, when the signal type is a second type different from the first
type, the first type is one of "split_coding_unit_flag" and "skip_flag", and the second type is one of "mvd_l0" and "mvd_l1".
With the structure, the image coding method can reduce the memory usage. More specifically, in the image coding method, since the control parameter of the upper block is not used for a control parameter of the second type, there is no need to
hold the control parameter of the second type of the upper block. With the structure, compared to the case where the left block and the upper block are used as uniformly "using a context model based on values of control parameters of neighboring
blocks", the memory usage can be reduced according to the image coding method. Furthermore, the image coding method can appropriately reduce the memory usage of the control parameter of the second type without, for example, failing to evaluate a BD-rate
Furthermore, the image decoding apparatus according to an aspect of the present invention is an image decoding apparatus using arithmetic decoding, and the apparatus includes: a context control unit configured to determine a context for use in a
current block to be processed, from among a plurality of contexts; an arithmetic decoding unit configured to perform arithmetic decoding on a bit sequence corresponding to the current block, using the determined context to reconstruct a binary sequence,
the bit sequence being obtained by performing arithmetic coding on a control parameter of the current block; and an inverse binarization unit configured to inversely binarize the binary sequence to reconstruct the control parameter of the current block,
wherein the context control unit is configured to: determine a signal type of the control parameter of the current block; determine the context under a first condition that decoded control parameters of neighboring blocks of the current block are used,
when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and determine the context under a second condition that the decoded control parameter of the upper block is not used, when the signal
type is a second type different from the first type, the first type is one of "split_coding_unit_flag" and "skip_flag", and the second type is one of "mvd_l0" and "mvd_l1".
Furthermore, the image coding apparatus according to an aspect of the present invention is an image coding apparatus using arithmetic coding, and the apparatus includes: a binarization unit configured to binarize a control parameter of a current
block to be processed to generate a binary sequence; a context control unit configured to determine a context for use in the current block, from among a plurality of contexts; and an arithmetic coding unit configured to perform arithmetic coding on the
binary sequence using the determined context to generate a bit sequence, wherein the context control unit is configured to: determine a signal type of the control parameter of the current block; determine the context under a first condition that control
parameters of neighboring blocks of the current block are used, when the signal type is a first type, the neighboring blocks being a left block and an upper block of the current block; and determine the context under a second condition that the control
parameter of the upper block is not used, when the signal type is a second type different from the first type, the first type is one of "split_coding_unit_flag" and "skip_flag", and the second type is one of "mvd_l0" and "mvd_l1".
The general or specific aspects may be implemented by a system, a method, an integrated circuit, a computer program, or a recording medium, or by an arbitrary combination of the system, the method, the integrated circuit, the computer program,
Embodiments described hereinafter indicate specific examples of the present invention. The values, shapes, materials, constituent elements, positions and connections of the constituent elements, steps, and orders of the steps indicated in
Embodiments are examples, and do not limit the present invention. The constituent elements in Embodiments that are not described in independent Claims that describe the most generic concept of the present invention are described as arbitrary constituent
An image coding apparatus according to Embodiment 1 of the present invention will be described. The image coding apparatus according to Embodiment 1 determines a context by switching between (1) using the upper block and (2) without using the
upper block, according to a signal type of a control parameter in arithmetic coding. With the structure, the deterioration in image quality can be suppressed, and memory usage can be reduced.
The image coding apparatus 100 in FIG. 1 is an image coding apparatus using arithmetic coding, and codes an input image signal 121 to generate a bitstream 124. The image coding apparatus 100 includes a control unit 101, a subtracting unit 102,
a transformation and quantization unit 103, a variable length coding unit 104, an inverse-quantization and inverse-transformation unit 105, an adding unit 106, an intra prediction unit 107, an inter prediction unit 108, and a switch 109.
The control unit 101 calculates a control parameter 130 based on the input image signal 121 to be coded. For example, the control parameter 130 includes information on a picture type of the input image signal 121 to be coded, a size of a unit
of motion prediction (prediction unit, PU) of the current block to be coded, and control information of the unit of motion prediction. Here, the control parameter 130 (control data) itself is to be coded. Thus, the control unit 101 outputs the control
parameter 130 to the variable length coding unit 104.
The inverse-quantization and inverse-transformation unit 105 inversely quantizes the quantized transform coefficients 123 into the frequency coefficient values and inversely transforms the obtained frequency coefficient values into a
reconstructed residual signal 125.
The intra prediction unit 107 performs intra prediction using the reconstructed image signal 126 to generate an image prediction signal 127. The inter prediction unit 108 performs inter prediction using the reconstructed image signal 126 to
generate an image prediction signal 128.
FIG. 2 is a functional block diagram of the variable length coding unit 104. The variable length coding unit 104 includes a binarizing unit 141, a context control unit 142, and a binary arithmetic coding unit 143. The following describes the
variable length coding process on the control parameter 130. Although the description about the variable length coding process on the quantized transform coefficients 123 is omitted, the process can be implemented, for example, using a known technique.
The binarization unit 141 binarizes the control parameter 130 to generate a binary sequence 151. More specifically, the binarization unit 141 is a processing unit that performs "II.1) binarization processing" according to NPL 1. The
binarization unit 141 transforms the control parameter 130 into the binary sequence 151 referred to as "bin string" for each signal type, according to a predetermined binarization method. The correspondence between the signal types and the binarization
methods will be described later. When the input control parameter 130 is one binary value, such as a flag, the binarization unit 141 outputs the control parameter 130 as the binary sequence 151 as it is.
The context control unit 142 determines a context for use in arithmetic coding of the control parameter 130 included in a current block to be processed, from among a plurality of contexts (a probability state table). Furthermore, the context
control unit 142 outputs a context index 152 specifying the determined context to the binary arithmetic coding unit 143.
More specifically, the context control unit 142 is a processing unit that performs "2) context modeling" according to NPL 1. The context control unit 142 sequentially receives a plurality of elements included in the binary sequence 151 output
from the binary arithmetic coding unit 143. The context control unit 142 selects one of the contexts to be used for the binary of the control parameter 130, according to the signal type of the control parameter 130 and an element position of the binary
in the binary sequence 151, and outputs, to the binary arithmetic coding unit 143, the context index 152 that is an index indicating the selected context.
Furthermore, the context control unit 142 holds the probability state table of values (context index values) obtained by dividing the elements in the binary sequence of the control parameter 130 into conditions of conditional probabilities, as
states of the context, and initializes and updates the probability state table.
Furthermore, the context control unit 142 holds a state (probability state index) for each occurrence condition .tau. (for each context), as a further division of a signal type (for each element number in the binary sequence of the control
parameter 130 when the number of elements in the binary sequence is two or more; the same will apply hereafter). The state is represented by the total 7-bit value by combining the occurrence probability P (internal ratio, typically, a 6-bit value) that
is the lower probability of one of two values 0 and 1, and a 1-bit value indicating which one of the values has the higher probability. Furthermore, holding a state means initializing and updating the state. For example, the updating corresponds to
changing the indexing that indicates a current probability state (that is, a probability) as a transition among 64 finite states as in H.264.
When an event X at the most probable side having the highest probability between the two values occurs, a ratio of the probability at the most probable side is slightly increased. For example, the context control unit 142 can slightly increase
the ratio of the probability at the most probable side by incrementing or decrementing, by 1, the value of the probability state index corresponding to 64 tables. On the other hand, when an event Not-X having the lower probability (against the predicted
probability) occurs, the context control unit 142 largely decreases the ratio of the held most probable probability based on a predetermined scale coefficient .alpha. (for example, .apprxeq.0.95) (see FIG. 6 of NPL 1). The context control unit 142
according to Embodiment 1 transitions and holds a state, based on a corresponding table index change value so as to be associated with the change in consideration of .alpha. as in H.264.
More specifically, the binary arithmetic coding unit 143 is a processing unit that performs "3) binary arithmetic coding" according to NPL 1. The binary arithmetic coding unit 143 performs arithmetic coding on the binary sequence 151 using the
context specified by the context index 152 to generate the bitstream 124. Here, the arithmetic coding is to handle events occurring for the control parameters 130 of various signal types as a cumulative sum of probabilities, and determine
correspondences between the events by narrowing down the range to a predetermined range on one number line.
First, the binary arithmetic coding unit 143 divides the one number line into two half sections, according to the occurrence probabilities of two possible values of the binary given from the context control unit 142. When the actual value
occurring for the binary (for example, 0) is a value with a higher probability (exceeding 0.5 (for example, 0.75)), the binary arithmetic coding unit 143 maintains the lower limit "Low" in the range on the number line without change, and sets a value
corresponding to a result of multiplying one time a scale coefficient 0.95 by the probability 0.75 this time, to a new range. On the other hand, when the actually generated binary value is a predicted value with a lower probability, the binary
arithmetic coding unit 143 shifts the lower limit "Low" by the higher probability, and changes the range according to the lower probability. The sections are held according to a cumulative sum of results of multiplications of the probability ranges. When a value with a lower probability successively occurs, the precision of the length of the range becomes soon lower than the precision that can be ensured by a computation. Here, the binary arithmetic coding unit 143 enlarges (renorms) the range to
maintain the precision, and outputs the bit sequence indicating the current range. Conversely, when a value with a higher probability (0.95, etc.) successively occurs, the probability values can bear a number of computations (state transitions in the
case of implementation by a table) until the length of the range becomes shorter than a predetermined length even with the multiplication of the values. Thus, the number of symbols that can be cumulated until the bit is output is many.
(c3) Binarization scheme indicates a binarization scheme to be applied to the control parameter 130 (SE) specified in the immediately left column. The binarization unit 141 performs the binarization process. In the column, "Fixed length" means
that the binarization unit 141 outputs the value of the control parameter 130 at the immediately left section as a binary sequence (bin string) of a fixed length. In HEVC, a signal type of the control parameter 130 whose name ends with "flag" is one
binary value of either 0 or 1. Thus, the binarization unit 141 outputs only the first element (binIdx=0) as the element of the binary sequence 151, and does not output the elements after the second element (binIdx>=1). In other words, the
binarization unit 141 outputs the value of the control parameter 130 as the binary sequence 151 as it is.
Furthermore, "Variable length" in the column means that the binarization unit 141 maps, to a binary sequence, the value of the control parameter 130 using binary sequences with respective variable lengths whose values are associated to have
binary lengths in ascending order of the occurrence frequencies (bin string or binary sequences each with the number of elements.gtoreq.1), and outputs the binary sequence. For example, the binarization unit 141 employs and outputs a scheme according to
the signal type, such as a (truncated) unary scheme, and a combination of the unary and other exponetional Golomb schemes (see "A. Binarization" of NPL 1). In the case of "Variable length", the number of elements of the binary sequence 151 is sometimes
limited to 1, or is equal to or larger than 2. An inverse binarization unit in an image decoding apparatus to be described later performs transformation inverse to the binarization scheme to reconstruct the input binary sequence into a multi-value or a
Regarding (c4) Context index of the first element (binIdx=0), the context control unit 142 indicates the choice of a context index (increment) to be applied to the first element included in a binary sequence generated according to the
binarization scheme specified in the column of c3. In the column, "0, 1, 2" indicates that the context control unit 142 selects and applies one of three probability state tables (contexts). For example, three context indexes with detailed conditions
are prepared for the one signal type "skip_flag", that is, three contexts are prepared, and the arithmetic coding is performed on the context indexes.
Similarly, "0, 1, 2, 3" in the column c4 indicates that the context to be applied to the first element (binIdx=0) included in the binary sequence 151 is selected from among one of four values, either 0, 1, 2, or 3. The binary sequence 151 is
obtained by mapping, to a binary sequence, the value of the control parameter 130 of the signal type specified in the column of c2, according to the binarization scheme in the column of c3. The conditional expressions in the column will be described
Regarding (c5) Left block condition L (condL), the context control unit 142 indicates the left block condition to select one of 0, 1, and 2 at the column c4. The left block condition L has a value of true or false determined according to the
value of the control parameter of the left block corresponding to the control parameter to be coded (or to be decoded).
Regarding (c6) Upper block condition A, the context control unit 142 indicates the upper block condition to select one of 0, 1, and 2 in coding or decoding elements of a sequence specified in the column c4. The upper block condition A has a
value of true or false determined according to the value of the control parameter of the upper block corresponding to the control parameter to be coded (or to be decoded). For example, in the case where the control parameter (SE) is skip_flag, the upper
block condition A has the value of true when skip_flag[xA][yA] indicates true (for example, 1), and has the value of false when it indicates false (for example, 0).
Although not illustrated, the signal type of more than two bits is associated with "(c7) Context increment to be applied to binIdx>=1". This (c7) indicates the context model applied by the context control unit 142 to a binary after the
second element in the binary sequence (binary value of a binary sequence element including an index value of binIdx>=1).
Next, the context control unit 142 obtains a basic value of a context for use in arithmetic coding of the control parameter 130 (S102). For example, the context control unit 142 determines the basic value according to the picture type (I, P, or
Next, the context control unit 142 determines a context value using one of the patterns 1 to 3, based on the signal type of the control parameter 130 (S103). Here, determining a context value is equivalent to determining an adjustment value
(increment value CtxIdxInc) for the basic value of the context.
First, the context control unit 142 determines the signal type of the control parameter 130 (S103). When the signal type of the control parameter 130 is the first type corresponding to the pattern 1 (the first type at S104), the context control
unit 142 determines a context value using a determination value derived from values of control parameters of two neighboring blocks (block A and block B) (S105). In other words, the context control unit 142 determines a context under a condition that
the control parameters of the two neighboring blocks of the left block and the upper block are used. Here, the context control unit 142 uses both of a result of the determination of (c5) condL and a result of the determination of (c6) condA in FIG. 3. Accordingly, data of one row of pictures are held for the control parameters of the first type.
On the other hand, when the signal type of the control parameter 130 is the second type corresponding to the pattern 2 (the second type at S104), the context control unit 142 determines a context value using a value of a control parameter of one
neighboring block (one immediately neighboring block in coding order) (S106). In other words, the context control unit 142 determines the context value under a condition that the control parameter of the upper block is not used.
On the other hand, when the signal type of the control parameter 130 is the third type corresponding to the pattern 3 (the third type at S104), the context control unit 142 fixedly determines a context value without using both of the control
parameters of the upper block and the left block (S107).
Finally, the binary arithmetic coding unit 143 performs arithmetic coding on the binary value of the first element using the context value specified by the context index value determined at Step S108 to generate the bit sequence (bitstream 124)
(S109).
Next, when the processes from Steps S102 to S109 are not executed on all the elements included in the binary sequence (No at S110), the variable length coding unit 104 performs the processes from Steps S102 to S109 on the next element included
in the binary sequence. On the other hand, when the processes from Steps S102 to S109 are completed on all the elements included in the binary sequence (Yes at S110), the variable length coding unit 104 ends the coding processing on the control
parameter of the current block.
As described above, the image coding apparatus 100 according to Embodiment 1 determines a context using the upper block in performing arithmetic coding on the control parameter of the first type, and determines a context without using the upper
block for the control parameters of the second and third types.
Compared to the case where the left block and the upper block are used as uniformly "using a context model based on values of control parameters of neighboring blocks", the image coding apparatus 100 can reduce the memory usage with the
configuration. Thus, the image coding apparatus 100 can suppress the deterioration in image quality, and reduce the memory usage.
FIG. 5 is a block diagram illustrating an image decoding apparatus 200 according to Embodiment 2. The image decoding apparatus 200 is an image decoding apparatus using arithmetic decoding, and decodes the bitstream 124 to generate an image
signal 229. Here, the bitstream 124 is, for example, generated by the image coding apparatus 100.
The image decoding apparatus 200 includes a control unit 201, a variable length decoding unit 202, an inverse quantization unit 204, an inverse transformation unit 205, an adding unit 206, an intra prediction unit 207, and an inter prediction
unit 208.
The variable length decoding unit 202 performs arithmetic decoding on the bitstream 124 to generate a control parameter 230 (control data syntax element) and quantized transform coefficients 223 (residual data syntax element values). The
control unit 201 receives the generated control parameter 230.
The inverse transformation unit 205 inversely transforms the orthogonal transform coefficients 224 to reconstruct a residual signal 225. The adding unit 206 adds the residual signal 225 to an image prediction signal (image signal 229) to
generate a decoded image signal 226.
The intra prediction unit 207 performs intra prediction using the decoded image signal 226 to generate an image prediction signal 227. The inter prediction unit 208 performs inter prediction using the decoded image signal 226 to generate an
image prediction signal 228.
FIG. 6 is a functional block diagram illustrating a configuration of the variable length decoding unit 202. The variable length decoding unit 202 includes a binary arithmetic decoding unit 243, a context control unit 242, and an inverse
binarization unit 241. The following describes the variable length decoding process on the control parameter 230. Although the description about the variable length decoding process on the quantized transform coefficients 223 is omitted, the process
can be implemented, for example, using a known technique.
The context control unit 242 determines a context for use in arithmetic decoding of the control parameter 230 of the current block, from among a plurality of contexts. Furthermore, the context control unit 242 outputs a context index 252
specifying the determined context to the binary arithmetic decoding unit 243.
More specifically, the context control unit 242 uses the same context model as that of the context control unit 142 in FIG. 2 as a held probability transition model. When the arithmetic coding unit 143 uses 64 probability states, the binary
arithmetic decoding unit 243 also holds the 64 probability states. This is because both the coder and the decoder need to interpret a range of the number line to be coded exactly in the same manner. Thus, the decoder uses the same pattern as the
pattern selected by the coder from among the three patterns 1 to 3.
The arithmetic decoding unit 243 performs arithmetic decoding on the bit sequence (bitstream 124) using the context determined by the context control unit 242 to reconstruct the binary sequence 251. More specifically, the arithmetic decoding
unit 243 reconstructs the input bit sequence into the binary sequence 251, according to the context (probability state table) specified by the context index given from the context control unit 242.
The inverse binarization unit 241 reconstructs the binary sequence 251 into a control parameter 230 if necessary through the inverse binarization process. As such, the context control unit 142 included in the image coding apparatus 100 and the
context control unit 242 included in the image decoding apparatus 200 use the same context model in both of the arithmetic coding and the arithmetic decoding of a control parameter of a certain signal type.
Next, the context control unit 242 determines a basic value of a context for use in arithmetic decoding of the control parameter to be decoded (S203). For example, the context control unit 242 determines the basic value according to the picture
type (I, P, or B).
Next, the context control unit 242 determines a context value using one of the patterns 1 to 3, based on the signal type of the control parameter (S204). Here, determining a context value is equivalent to determining an adjustment value
(increment value CtxIdxInc) for the basic value of the context. For example, the context control unit 242 statically determines one of the patterns 1 to 3 based on the signal type of the control parameter by following a predetermined table.
The context control unit 242 switches between neighboring blocks for use in determining a context for obtaining a binary value of the first element included in the binary sequence 251 using the arithmetic decoding, according to the signal type
of the control parameter.
First, the context control unit 242 determines the signal type of the control parameter 230 (S205). When the signal type is the first type corresponding to the pattern 1 (the first type at S205), the context control unit 242 determines a
context value using control parameters of two neighboring blocks (S206). In other words, the context control unit 242 determines the context value under a condition that decoded control parameters of the two neighboring blocks of the left block and the
upper block are used.
On the other hand, when the signal type is the second type corresponding to the pattern 2 (the second type at S205), the context control unit 242 determines a context value using a value of a control parameter of one neighboring block (one
immediately neighboring block in coding order) (S207). In other words, the context control unit 242 determines the context value under a condition that the decoded control parameter of the upper block is not used.
On the other hand, when the signal type is the third type corresponding to the pattern 3 (the third type at S205), the context control unit 242 fixedly determines a context value (S208). In other words, the context control unit 242 determines
the context value under a condition that the decoded control parameters of the upper block and the left block are not used.
Next, when the processes from Steps S203 to S210 are not executed on all the elements included in the binary sequence (No at S211), the variable length decoding unit 202 performs the processes from Steps S203 to S210 on the next element included
in the binary sequence.
On the other hand, when the processes from Steps S203 to S210 are completed on all the elements included in the binary sequence (Yes at S211), the inverse binarization unit 241 changes one or more of the elements of the binary sequence 251
obtained by repeating the processes from Steps S203 to S210 more than one time to generate the control parameter 230 (S212).
As described above, the image decoding apparatus 200 according to Embodiment 2 determines a context using the upper block in performing arithmetic decoding on the control parameter of the first type, and determines a context without using the
upper block for the control parameters of the second and third types.
Compared to the case where the left block and the upper block are used as uniformly "using a context model based on values of control parameters of neighboring blocks", the image decoding apparatus 200 can reduce the memory usage with the
configuration. Thus, the image decoding apparatus 200 can suppress the deterioration in image quality, and reduce the memory usage.
Furthermore, the context control unit 142 or 242 may change a method of switching between the context models selected in such a manner (including a case where the context model increment is changed; the same will apply hereafter) according to
predetermined image information. For example, the context control unit 142 or 242 may further switch the switching policy itself, according to the amount of memory, or the size of the horizontal width or a sampling format of an image that affects the
number of trainings of each context.
Although the context control unit 142 or 242 switches between using and not using the upper block condition as the simplified description, the context control unit 142 or 242 may combine a case where the upper block is not available to the
switching and apply the combined case. For example, the context control unit 142 or 242 may change the switching policy itself, according to whether or not a slice to be processed is an entropy slice (entropy_slice_flag indicates 1 or 0). Similarly,
when the availability of the upper neighboring block cannot be ensured, the context control unit 142 or 242 may change the switching policy so as not to use the upper block.
For example, as illustrated in FIG. 8, the context control unit 142 or 242 may switch the determination policy of the context model between the first determination criterion (S302) and the second determination criterion (S303), according to a
value of a parameter of a predetermined unit. Here, "according to a value of a parameter of a predetermined unit" means according to whether or not a slice is an entropy slice as described above. Furthermore, the first determination criterion is a
criterion based on which the processes in FIG. 7 are performed. The second determination criterion is a criterion excluding Step S204 in FIG. 7, and is, for example, a conventional criterion. This is equivalent to determining the context index
increment, using a parameter of a predetermined local unit and a value of a parameter of a unit larger than the predetermined local unit.
Furthermore, the context control unit 142 or 242 may change the determination criterion to be used, according to the characteristics of an image system. For example, the context control unit 142 or 242 may change the determination criterion to
be used, according to intervals of I-pictures (setting values of IntraPeriod).
Furthermore, the context control unit 142 or 242 may determine whether or not a control parameter of the upper block is used, according to whether or not the control parameter of the upper block is available in coding or decoding based on a
position of the control parameter. In other words, the context control unit 142 or 242 may determine whether or not the control parameter of the upper block is available in decoding, based on a position of the current block, and determine a context
using one of the patterns 2 and 3 when the control parameter of the upper block is not available. Furthermore, the context control unit 142 or 242 may determine whether or not a reference value of the upper block is available based on a tree structure
for partitioning TU, CU, or PU blocks. In other words, the context control unit 142 or 242 may determine whether or not the control parameter of the upper block is available in decoding, according to the hierarchical depth of a data unit to which each
of the control parameters to be processed belongs.
FIG. 9 illustrates a relationship between a picture, slices, and blocks in accordance with the HEVC standard. One picture is partitioned into one or more slices. In the example of FIG. 9, the picture is partitioned into two slices (SLICE 1 and
SLICE 2). One of the slices includes blocks 301 (for example, treeblocks). Here, the block 301 is the largest unit as a certain control unit when a slice is partitioned in a predetermined size, and has a size of a root when the unit is at the root in
the hierarchically-partitioned structure.
In the example of FIG. 9, SLICE 2 starts from a block 301A, and is composed of one sequence including blocks to the bottom right corner of the picture through the hatched blocks 301B and 301C. One of the hatched blocks in FIG. 9 is one block
(TreeBlock) to be currently processed.
Each of the blocks 301 includes N.times.M pixels. One of the blocks 301 is recursively partitioned inside (typically into four). In other words, one TreeBlock conceptually composes one quad tree. In the block 301B in FIG. 9, the upper right
block obtained by partitioning the hatched block 301B into four are recursively partitioned into four blocks twice. In other words, the block 301B includes 10 logical units from the upper-left zero-th unit to the lower-right ninth unit that are
partitioned with a certain perspective.
Here, the perspective indicates the concept of a plurality of trees having different depths with a root as a base point, such as a tree regarding a coding unit (CU) and a tree regarding residual_data. Here, a value of each control parameter
belongs to one of leaf nodes.
Here, whether or not a value of a control parameter of a certain signal type included in an upper block is actually available depends on a type of a tree to which the control parameter belongs. Thus, the context control unit 142 or 242 may
change a determination criterion according to a type of a tree to which the control parameter belongs. This change is equivalent to the change to a syntax unit. For example, the context control unit 142 or 242 may use the pattern 2 or 3 in which the
upper block is not used for data of an adaptive filter with a data structure such as alf_param, whereas it may use the context model policy (pattern 1) for the other syntaxes as conventionally used. In other words, the second type or the third type may
be a control parameter having a predetermined data structure. Furthermore, this means that the determination criterion may be changed according to the type of a tree of a neighboring block.
Furthermore, whether or not the value of the control parameter can be actually used or produces the advantage of reducing the memory usage differs depending on a position of a block in the hierarchical relationship. In other words, the context
control unit 142 or 242 may switch between using or not using the upper block, according to a depth of a block and a hierarchical position of the block.
Furthermore, in order to reduce memory usage, the context control unit 142 or 242 may select the pattern 1 using the upper block, when the block is not at a depth 0 and the own position is one of the second to the subsequent elements in the
vertical partitioning. Here, "depth" indicates the depth from the root. In other words, when a certain block is defined as block[xn],[y0][depth], the determination criterion may be changed according to whether or not the current block satisfies
block[xn][(y0)+1][depth]. In other words, the upper blocks are used for the blocks 4 to 9 in FIG. 9. When the tree is coded or decoded in the order as numbered (starting from 0 and ending at 9), it is clear that the blocks 4 to 9 can use the control
parameters included in the upper blocks. Furthermore, there is an advantage that these blocks have only to temporally hold data. Furthermore, this indicates that the context value is determined according to the 3D position including the depth in
addition to the x and y coordinates. Besides, a conditional value of a block in the higher layer can be used (followed) as a conditional value of a block in the lower layer.
Furthermore, the context control unit 142 or 242 may change these criteria in consideration of the position relationship between the current block and the other slices. Hereinafter, the three hatched blocks 301A, 301B, and 301C in FIG. 9 will
Here, the block 301A is a start block, and both of the left block and the upper block of the block 301A are included in another slice. The upper block of the block 301B is included in another slice. Both of the left block and the upper block
of the block 301C are included in the same slice including the block 301C. The context control unit 142 or 242 may switch the criterion according to such a condition. In other words, the context control unit 142 or 242 may switch the criterion (i)
according to whether or not the upper block is included in another slice, (ii) according to whether or not the left block is included in another slice, or (iii) according to both (i) and (ii). In other words, the context control unit 142 or 242 may
determine that the control parameter of the upper block is not available in decoding when the current block is at the slice boundary. Accordingly, when the decoding processing on the upper SLICE 1 is not completed, for example, it is possible to perform
the decoding processing in consideration of whether or not SLICE 2 can obtain information by itself.
The image coding apparatus 100 codes moving pictures on a per processing unit, and the image coding apparatus 200 decodes a coded stream on a per processing unit. The processing unit is layered by partitioning the processing unit into small
processing units and further partitioning the small processing units into smaller processing units. As the processing unit is smaller, the depth of the processing unit is greater and is hierarchically lower, and the value indicating the depth is larger. Conversely, as the processing unit is larger, the depth of the processing unit is less and is hierarchically higher, and the value indicating the depth is smaller.
The processing unit includes a coding unit (CU), a prediction unit (PU), and a transformation unit (TU). A CU is a block of 128.times.128 pixels at maximum, and is a unit corresponding to a conventional macroblock. A PU is a basic unit for the
inter prediction. A TU is a basic unit for orthogonal transformation, and has a size identical to that of PU or much smaller than PU. A CU is, for example, partitioned into 4 sub-CUs, and one of the sub-CUs includes a PU and a TU having the same size
as that of the sub-CU (here, PU and TU overlap one another). For example, the PU is further partitioned into 4 sub-PUs, and the TU is further partitioned into 4 sub-CUs. When the processing unit is partitioned into smaller processing units, each of the
smaller processing units is referred to as a sub-processing unit. For example, when the processing unit is a CU, the sub-processing unit is a sub-CU. When the processing unit is a PU, the sub-processing unit is a sub-PU. Furthermore, when the
processing unit is a TU, the sub-processing unit is a sub-TU.
Each of the coding units including the respective largest coding units is partitioned into four coding units. As a result, a quad tree having the size of a CU is constructed. The position of the CU is indicated by a coding unit index cuIdx
having a sample (pixel or coefficients) at the upper left corner of the largest coding unit as a starting point.
When partitioning of a CU is not permitted, the CU is handled as a PU. Similarly as the CU, the position of a PU is indicated by a prediction unit index puIdx having a sample at the upper left corner of the largest coding unit as a starting
The PU may include TUs. Similarly as the CU, the TU may be partitioned into four smaller TUs (sub-TUs). This indicates the permission of the quad tree partitioning of a residual signal. The position of the TU is indicated by a transformation
unit index tuIdx having a sample at the upper left corner of the PU as a starting point.
PU (prediction unit): Basic unit for identifying prediction processing. A PU is as large as a CU in which partitioning is not permitted. Although partitioning a CU into four square regions is permitted, a PU can be partitioned into a plurality
of partitions having any shape;
Furthermore, quantization parameters include at least one of a delta quantization scale parameter (delta QP or QP delta), a quantization offset parameter, an index (Q matrix select idc), and a quantization dead zone offset parameter. The index
is for selecting one of quantized scaling matrices.
The delta quantization scale parameter (delta QP or QP delta) is a difference between a quantization scale parameter to be applied to transform coefficients and a quantization scale parameter specified by a sequence header or a slice header (or
a quantization scale parameter immediately before in Z scanning order).
The quantization offset parameter is also referred to as a quantization offset, and is an adjustment value (offset value) for rounding a signal in performing quantization. Thus, when the image coding apparatus 100 performs quantization, it
codes the quantization offset. Then, the image decoding apparatus 200 decodes the coded quantization offset. Next, the image decoding apparatus 200 performs correction using the quantization offset when inversely quantizing the transform coefficients.
An index (Qmatrix select idc) is referred to as an adaptive quantization matrix, and indicates which quantization scaling matrix is used from among a plurality of quantization scaling matrices. Furthermore, when there is only one quantization
scaling matrix, Qmatrix select idc indicates whether or not the quantization scaling matrix is used. The adaptive quantization matrix can be controlled per block unit (processing unit).
The quantization dead zone offset parameter is referred to as an adaptive dead zone, and is control information for adaptively changing a dead zone per block. The dead zone is a width whose frequency coefficients become 0 by quantization (last
width that becomes +1 or -1 after the quantization).
Although a case where the pattern 3 with which a predetermined fixed value is used as a context value is described hereinbefore, the case may be performed under the condition that the control parameters of the upper block and the left block are
not used, and further under the condition without using the control parameters of the upper block and the left block as the pattern 3. For example, the context control unit 142 or 242 may determine a context according to the hierarchical depth of a data
unit to which each of the control parameters belongs, as the pattern 3.
More specifically, the present inventors have verified each of the signal types below among the signal types as indicated in FIG. 3 (Section 9.3.3.1.1.1 of NPL 2). Each of the signal types has been verified, because there are various
parameters, and it is difficult to predict whether or not each pattern of the other signal types satisfies the validity, based on a result of the verification on one of the signal types (which one of the patterns 1 to 3 is appropriate).
The verification is in conformity with the structure (setting parameter and software version HM3.0) described in JCTVC-E700, "Common test conditions and software reference configurations" (see NPL 3). Furthermore, each of the test images has a
length limited to 49 frames.
The image coding method and the image decoding method according to Embodiment 3 relate to CABAC. Thus, the verification has been conducted using the following four test patterns that are a set of setting values each indicating 1 as the value of
Symbol Mode (#0:LCEC, 1: CABAC):
The evaluation is made based on an evaluation value called a "BD-rate" that is used as an evaluation standard uniformly used for an implementation evaluation in HEVC. Y BD-rate, U BD-rate, and V BD-rate are BD-rates for a YUV color space, and
are evaluation standard values. According to VCEG-AI11 (NPL 4), the BD-rate is an evaluation value obtained by integrating two pairs of code amounts with a result of PSNR, and representing the coding efficiency according to the area ratio. Furthermore,
the BD-rate indicating a minus value means that the coding efficiency has been improved. The comparison criteria are based on a result of the output of a reference program which implements the pattern 1. The results of the patterns 2 and 3 are shown
with respect to the result of the pattern 1.
The verification is conducted by changing the context model from the pattern 1 to the pattern 2 or 3 only for a signal type to be verified, without changing the context model for the other signal types and the verification parameter specified in
NPL 3. In the column in FIG. 11, the value of "Fixed" indicates that the condition (the left block condition or the upper block condition) of the column specified by "Fixed" is not used when a context value (or increment) is derived. In other words,
when only one of the left block condition and the upper block condition is "Fixed", only the other condition is used. Furthermore, when both of the left block condition and the upper block condition are "Fixed", a predetermined value (for example, 0) is
used as a context value (or increment).
split_coding_unit_flag[x0][y0] specifies whether a coding unit is split into coding units with half horizontal and vertical size. The array indices x0, y0 specify the location (x0, y0) of the top-left luma sample of the considered coding block
relative to the top-left luma sample of the picture. In other words, "split_coding_unit_flag" indicates whether or not the target CU is partitioned into four. More specifically, the target CU is partitioned when split_coding_unit_flag indicates 1,
whereas the target CU is not partitioned when split_coding_unit_flag indicates 0.
FIG. 12A indicates the result of the verification using one neighboring block (only a determination value of the left block condition L) of the pattern 2. FIG. 12B indicates the result of the verification using zero neighboring block (using
neither the upper block condition L nor the left block condition L) of the pattern 3.
Furthermore, the evaluation value is represented by the evaluation standard indicating a value relative to an evaluation value in the case of the pattern 1 in which both of the left block and the upper block are used. More specifically, when
the evaluation value is positive, the result is inferior to the evaluation value (BD-rate) in the case of the pattern 1. Furthermore, when the evaluation value is negative, the result is more improved than the evaluation value in the case of the pattern
skip_flag[x0][y0] equal to 1 specifies that for the current coding unit, when decoding a P or B slice, no more syntax elements except the motion vector predictor indices are parsed after skip_flag[x0][y0]. skip_flag[x0][y0] equal to 1 specifies
that the coding unit is not to be skipped. The array indices x0, y0 specify the location (x0, y0) of the top-left luma sample of the considered coding block relative to the top-left luma sample of the picture. In other words, skip_flag indicates
whether or not the target CU is to be skipped (handled as a skipped block).
FIG. 14A indicates the result of the verification using one neighboring block (only a determination value of the left block condition L) of the pattern 2. FIG. 14B indicates the result of the verification using zero neighboring block (using
The result of the verification in each of FIGS. 14A and 14B indicates the increment and decrement of the BD-rate according to the four test patterns as described for the first verification. Furthermore, the meaning of the evaluation value is
the same as that of the first verification.
mvd_l0[x0][y0][compIdx] specifies the difference between a list 0 vector component to be used and its prediction. The array indices x0, y0 specify the location (x0, y0) of the top-left luma sample of the considered prediction block relative to
the top-left luma sample of the picture. The horizontal motion vector component difference is assigned compIdx=0 and the vertical motion vector component is assigned compIdx=1. When any of the two components is not present, the inferred value is 0. In
other words, mvd_l0 represents a difference between a motion vector at a PU position (xP, yP) and the predicted vector, using a first component (horizontal component compIdx=0) and a second component (vertical component compIdx=1).
Furthermore, mvd_lc[x0][y0][compIdx] has the same semantics as mvd_l0, with 10 and list 0 replaced by lc and list combination, respectively. In other words, mvd_lc is generated by combining mvd_l0 and mvd_l1.
FIG. 16A indicates the result of the verification using one neighboring block (only a determination value of the left block condition L) of the pattern 2. FIG. 16B indicates the result of the verification using zero neighboring block (using
The result of the verification in each of FIGS. 16A and 16B indicates the increment and decrement of the BD-rate according to the four test patterns as described for the first verification. Furthermore, the meaning of the evaluation value is
The result is different from those of the first verification of split_coding_unit_flag and the second verification of skip_flag. There is no significant difference in BD-rate between the patterns 1 and 2 or 3 as a pattern of a context model for
Thus, under a mixed environment with a plurality of control parameters of signal types, the context control unit 142 or 242 determines a context value without using the upper block as a neighboring block particularly when the signal type of the
control parameter is mvd_l0(l1,lc). In other words, the context control unit 142 or 242 determines a context value using the pattern 2 or 3 when the signal type of the control parameter is mvd_l0(l1,lc). In other words, the first type includes
"split_coding_unit_flag" or "skip_flag", and the second type or the third type includes mvd_l0, mvd_l1, or mvd_lc. Accordingly, the image coding apparatus and the image decoding apparatus according to Embodiment 3 can reduce memory usage while
suppressing the decrease in the BD-rate.
When the pattern 2 is compared with the pattern 3 for mvd, these BD-rates have no significant difference. Thus, it is preferred to use the pattern 3 for mvd_l0(l1,lc). Accordingly, it is possible to further reduce the memory usage and the
processing amount.
Here, although residual data (mvd) of a motion vector is not transmitted in a skip mode, the residual data (mvd) of the motion vector is transmitted in a merge mode. Accordingly, even when the context to be temporarily used is not optimal in
the merge mode, the deterioration in the image quality caused by not using the optimal context can be compensated to some extent with the processing using the mvd Accordingly, the deterioration in the image quality is suppressed when the surrounding
block for mvd is not used.
More specifically, the context control unit 142 or 242 may derive a conditional value of another signal type having a conditional value dependent on conditional values (condL or condA) of two signal types from among the three signal types of
mvd_l0, mvd_l1, and mvd_lc, using the conditional values.
For example, when a value of condA for mvd_lc is dependent on the conditional values (a value of condA for 10 and a value of condA for 11) of the two signal types of mvd_l0 and lvd_l1, the context control unit 142 or 242 does not need to refer
to the value of condA for mvd_lc.
As indicated in FIG. 16D, the context control unit 142 and 242 may derive the conditional values of condL and condA for mvd_lc from at least one of the conditional values of mvd_l0 and mvd_l1 in the same block.
Furthermore, the context control unit 142 and 242 may use the dependency between compIdx=0 and 1. In other words, the context control unit 142 and 242 may cause a result of one of the two conditional values of the horizontal direction mvd_l0[
][ ][0] and the vertical direction mvd_l0[ ][ ][1] to depend on the other. In other words, the context control unit 142 and 242 may derive the conditional values condL and condA of one of the horizontal direction and the vertical direction for mvd, from
the other of the conditional values for mvd. Here, according to NPL 2, a context index (index increment+reference value) is set to each of the horizontal directions mvd_l0[ ][ ][0], mvd_l1[ ][ ][0], and mvd_lc[ ][ ][0], and the vertical directions
mvd_l0[ ][ ][1], mvd_l1[ ][ ][1], and mvd_lc[ ][ ][1]. Thus, it is possible to reduce the wastes using the dependency. In other words, the number of context indexes can be reduced.
Here, the conditional values of the upper block and the left block are used only for the first bit of mvd according to NPL 2. In other words, the context control unit 142 and 242 may use the pattern 2 or 3 for the first bit of mvd. In other
words, the context control unit 142 and 242 may use the pattern 2 or 3 for abs_mvd_greater0_flag[compIdx] indicating whether or not a difference between a motion vector and the predicted vector is equal to or larger than 0.
Furthermore, the divisions of the functional blocks in the block diagrams are examples. Thus, the functional blocks may be implemented as one functional block, one functional block may be divided into a plurality of functional blocks, and a
part of the functions may be switched to another functional block. Furthermore, a plurality of functional blocks having similar functions may be processed by single hardware or software in parallel or with time division.
The orders of the steps of the image coding method performed by the image coding apparatus and the image decoding method performed by the image decoding apparatus are for specifically describing the present invention, and may be an order other
than the above orders. Furthermore, part of the steps may be performed simultaneously (in parallel) with the other steps.
The processing described in each of Embodiments can be simply implemented by a computer system by recording, onto a recording medium, a program for implementing the structure of the moving image coding method or the moving image decoding method
described in Embodiment. The recording medium may be any recording medium as long as the program can be recorded thereon, such as a magnetic disk, an optical disc, a magnetic optical disc, an IC card, and a semiconductor memory.
FIG. 19 illustrates an overall configuration of a content providing system ex100 for implementing content distribution services. The area for providing communication services is divided into cells of desired size, and base stations ex106 to
ex110 which are fixed wireless stations are placed in each of the cells.
The content providing system ex100 is connected to devices, such as a computer ex111, a personal digital assistant (PDA) ex112, a camera ex113, a cellular phone ex114 and a game machine ex115, via an Internet ex101, an Internet service provider
ex102, a telephone network ex104, as well as the base stations ex106 to ex110.
However, the configuration of the content providing system ex100 is not limited to the configuration shown in FIG. 19, and a combination in which any of the elements are connected is acceptable. In addition, each of the devices may be directly
The camera ex113, such as a digital video camera, is capable of capturing moving images. A camera ex116, such as a digital video camera, is capable of capturing both still images and moving images. Furthermore, the cellular phone ex114 may be
the one that meets any of the standards such as Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Wideband-Code Division Multiple Access (W-CDMA), Long Term Evolution (LTE), and High Speed Packet Access (HSPA). Alternatively, the cellular phone ex114 may be a Personal Handyphone System (PHS).
In the content providing system ex100, a streaming server ex103 is connected to the camera ex113 and others via the telephone network ex104 and the base station ex109, which enables distribution of a live show and others. For such a
distribution, a content (for example, video of a music live show) captured by the user using the camera ex113 is coded as described above in each of Embodiments, and the coded content is transmitted to the streaming server ex103. On the other hand, the
streaming server ex103 carries out stream distribution of the received content data to the clients upon their requests. The clients include the computer ex111, the PDA ex112, the camera ex113, the cellular phone ex114, and the game machine ex115 that
are capable of decoding the above-mentioned coded data. Each of the devices that have received the distributed data decodes and reproduces the coded data.
decoded by the clients or the streaming server ex103, or the decoding processes may be shared between the clients and the streaming server ex103. Furthermore, the data of the still images and moving images captured by not only the camera ex113 but also
the camera ex116 may be transmitted to the streaming server ex103 through the computer ex111. The coding processes may be performed by the camera ex116, the computer ex111, or the streaming server ex103, or shared among them.
Furthermore, generally, the computer ex111 and an LSI ex500 included in each of the devices perform such coding and decoding processes. The LSI ex500 may be configured of a single chip or a plurality of chips. Software for coding and decoding
moving images may be integrated into some type of a recording medium (such as a CD-ROM, a flexible disk, a hard disk) that is readable by the computer ex111 and others, and the coding and decoding processes may be performed using the software. Furthermore, when the cellular phone ex114 is equipped with a camera, the video data obtained by the camera may be transmitted. The video data is data coded by the LSI ex500 included in the cellular phone ex114.
As described above, the clients can receive and reproduce the coded data in the content providing system ex100. In other words, the clients can receive and decode information transmitted by the user, and reproduce the decoded data in real time
The present invention is not limited to the above-mentioned content providing system ex100, and at least either the moving image coding apparatus or the moving image decoding apparatus described in each of Embodiments can be incorporated into a
digital broadcasting system ex200 as shown in FIG. 20. More specifically, a broadcast station ex201 communicates or transmits, via radio waves to a broadcast satellite ex202, multiplexed data obtained by multiplexing the audio data and the video data. The video data is data coded according to the moving image coding method described in each of Embodiments. Upon receipt of the video data, the broadcast satellite ex202 transmits radio waves for broadcasting. Then, a home-use antenna ex204 capable of
receiving a satellite broadcast receives the radio waves. A device, such as a television (receiver) ex300 and a set top box (STB) ex217, decodes the received multiplexed data and reproduces the data.
Furthermore, a reader/recorder ex218 that (i) reads and decodes the multiplexed data recorded on a recording media ex215, such as a DVD and a BD, or (ii) codes video signals in the recording medium ex215, and in some cases, writes data obtained
by multiplexing an audio signal on the coded data can include the moving image decoding apparatus or the moving image coding apparatus as shown in each of Embodiments. In this case, the reproduced video signals are displayed on the monitor ex219, and
another apparatus or system can reproduce the video signals, using the recording medium ex215 on which the multiplexed data is recorded. Furthermore, it is also possible to implement the moving image decoding apparatus in the set top box ex217 connected
to the cable ex203 for a cable television or the antenna ex204 for satellite and/or terrestrial broadcasting, so as to display the video signals on the monitor ex219 of the television ex300. The moving image decoding apparatus may be included not in the
set top box but in the television ex300.
FIG. 21 illustrates the television (receiver) ex300 that uses the moving image coding method and the moving image decoding method described in each of Embodiments. The television ex300 includes: a tuner ex301 that obtains or provides
multiplexed data obtained by multiplexing the audio data and the video data through the antenna ex204 or the cable ex203, etc. that receives a broadcast; a modulation/demodulation unit ex302 that demodulates the received multiplexed data or modulates
data into multiplexed data to be supplied outside; and a multiplexing/demultiplexing unit ex303 that demultiplexes the modulated multiplexed data into video data and audio data, or multiplexes the video data and audio data coded by the signal processing
unit ex306 into data.
Furthermore, the television ex300 further includes: a signal processing unit ex306 including an audio signal processing unit ex304 and a video signal processing unit ex305 that decode audio data and video data and code audio data and video data,
respectively; a speaker ex307 that provides the decoded audio signal; and an output unit ex309 including a display unit ex308 that displays the decoded video signal, such as a display. Furthermore, the television ex300 includes an interface unit ex317
including an operation input unit ex312 that receives an input of a user operation. Furthermore, the television ex300 includes a control unit ex310 that controls overall each constituent element of the television ex300, and a power supply circuit unit
ex311 that supplies power to each of the elements. Other than the operation input unit ex312, the interface unit ex317 may include: a bridge ex313 that is connected to an external device, such as the reader/recorder ex218; a slot unit ex314 for enabling
attachment of the recording medium ex216, such as an SD card; a driver ex315 to be connected to an external recording medium, such as a hard disk; and a modem ex316 to be connected to a telephone network. Here, the recording medium ex216 can
electrically record information using a non-volatile/volatile semiconductor memory element for storage. The constituent elements of the television ex300 are connected to one another through a synchronous bus.
First, a configuration in which the television ex300 decodes the multiplexed data obtained from outside through the antenna ex204 and others and reproduces the decoded data will be described. In the television ex300, upon receipt of a user
operation from a remote controller ex220 and others, the multiplexing/demultiplexing unit ex303 demultiplexes the multiplexed data demodulated by the modulation/demodulation unit ex302, under control of the control unit ex310 including a CPU. Furthermore, the audio signal processing unit ex304 decodes the demultiplexed audio data, and the video signal processing unit ex305 decodes the demultiplexed video data, using the decoding method described in each of Embodiments, in the television
ex300. The output unit ex309 provides the decoded video signal and audio signal outside. When the output unit ex309 provides the video signal and the audio signal, the signals may be temporarily stored in buffers ex318 and ex319, and others so that the
signals are reproduced in synchronization with each other. Furthermore, the television ex300 may read the multiplexed data not through a broadcast and others but from the recording media ex215 and ex216, such as a magnetic disk, an optical disc, and an
SD card. Next, a configuration in which the television ex300 codes an audio signal and a video signal, and transmits the data outside or writes the data on a recording medium will be described. In the television ex300, upon receipt of a user operation
from the remote controller ex220 and others, the audio signal processing unit ex304 codes an audio signal, and the video signal processing unit ex305 codes a video signal, under control of the control unit ex310 using the image coding method as described
in each of Embodiments. The multiplexing/demultiplexing unit ex303 multiplexes the coded video signal and audio signal, and provides the resulting signal outside. When the multiplexing/demultiplexing unit ex303 multiplexes the video signal and the
audio signal, the signals may be temporarily stored in buffers ex320 and ex321, and others so that the signals are reproduced in synchronization with each other. Here, the buffers ex318 to ex321 may be plural as illustrated, or at least one buffer may
be shared in the television ex300. Furthermore, data may be stored in a buffer other than the buffers ex318 to ex321 so that the system overflow and underflow may be avoided between the modulation/demodulation unit ex302 and the
multiplexing/demultiplexing unit ex303, for example.
obtained data. Although the television ex300 can code, multiplex, and provide outside data in the description, it may be not capable of performing all the processes but capable of only one of receiving, decoding, and providing outside data.
Furthermore, when the reader/recorder ex218 reads or writes the multiplexed data from or in a recording medium, one of the television ex300 and the reader/recorder ex218 may decode or code the multiplexed data, and the television ex300 and the
As an example, FIG. 22 illustrates a configuration of an information reproducing/recording unit ex400 when data is read or written from or in an optical disc. The information reproducing/recording unit ex400 includes constituent elements ex401
to ex407 to be described hereinafter. The optical head ex401 irradiates a laser spot on a recording surface of the recording medium ex215 that is an optical disc to write information, and detects reflected light from the recording surface of the
recording medium ex215 to read the information. The modulation recording unit ex402 electrically drives a semiconductor laser included in the optical head ex401, and modulates the laser light according to recorded data. The reproduction demodulating
unit ex403 amplifies a reproduction signal obtained by electrically detecting the reflected light from the recording surface using a photo detector included in the optical head ex401, and demodulates the reproduction signal by separating a signal
component recorded on the recording medium ex215 to reproduce the necessary information. The buffer ex404 temporarily holds the information to be recorded on the recording medium ex215 and the information reproduced from the recording medium ex215. A
disk motor ex405 rotates the recording medium ex215. A servo control unit ex406 moves the optical head ex401 to a predetermined information track while controlling the rotation drive of the disk motor ex405 so as to follow the laser spot. The system
control unit ex407 controls overall the information reproducing/recording unit ex400. The reading and writing processes can be implemented by the system control unit ex407 using various information stored in the buffer ex404 and generating and adding
new information as necessary, and by the modulation recording unit ex402, the reproduction demodulating unit ex403, and the servo control unit ex406 that record and reproduce information through the optical head ex401 while being operated in a
coordinated manner. The system control unit ex407 includes, for example, a microprocessor, and executes processing by causing a computer to execute a program for read and write.
FIG. 23 schematically illustrates the recording medium ex215 that is the optical disc. On the recording surface of the recording medium ex215, guide grooves are spirally formed, and an information track ex230 records, in advance, address
information indicating an absolute position on the disk according to change in a shape of the guide grooves. The address information includes information for determining positions of recording blocks ex231 that are a unit for recording data. An
apparatus that records and reproduces data reproduces the information track ex230 and reads the address information so as to determine the positions of the recording blocks. Furthermore, the recording medium ex215 includes a data recording area ex233,
an inner circumference area ex232, and an outer circumference area ex234. The data recording area ex233 is an area for use in recording the user data. The inner circumference area ex232 and the outer circumference area ex234 that are inside and outside
of the data recording area ex233, respectively are for specific use except for recording the user data. The information reproducing/recording unit 400 reads and writes coded audio data, coded video data, or multiplexed data obtained by multiplexing the
coded audio data and the coded video data, from and on the data recording area ex233 of the recording medium ex215.
Although an optical disc having a layer, such as a DVD and a BD is described as an example in the description, the optical disc is not limited to such, and may be an optical disc having a multilayer structure and capable of being recorded on a
part other than the surface. Furthermore, the optical disc may have a structure for multidimensional recording/reproduction, such as recording of information using light of colors with different wavelengths in the same portion of the optical disc and
recording information having different layers from various angles.
Furthermore, the car ex210 having the antenna ex205 can receive data from the satellite ex202 and others, and reproduce video on the display device such as the car navigation system ex211 set in the car ex210, in a digital broadcasting system
ex200. Here, a configuration of the car navigation system ex211 will be the one for example, including a GPS receiving unit in the configuration illustrated in FIG. 21. The same will be true for the configuration of the computer ex111, the cellular
FIG. 24A illustrates the cellular phone ex114 that uses the moving image coding method and the moving image decoding method described in each of Embodiments. The cellular phone ex114 includes: an antenna ex350 for transmitting and receiving
radio waves through the base station ex110; a camera unit ex365 capable of capturing moving and still images; and a display unit ex358 such as a liquid crystal display for displaying the data such as decoded video captured by the camera unit ex365 or
received by the antenna ex350. The cellular phone ex114 further includes: a main body unit including a set of operation keys ex366; an audio output unit ex357 such as a speaker for output of audio; an audio input unit ex356 such as a microphone for
input of audio; a memory unit ex367 for storing captured video or still pictures, recorded audio, coded or decoded data of the received video, the still images, e-mails, or others; and a slot unit ex364 that is an interface unit for a recording medium
that stores data in the same manner as the memory unit ex367.
Next, an example of a configuration of the cellular phone ex114 will be described with reference to FIG. 24B. In the cellular phone ex114, a main control unit ex360 designed to control overall each unit of the main body including the display
conversion and the analog-to-digital conversion on the data.
Then, the modulation/demodulation unit ex352 performs inverse spread spectrum processing on the data, and the audio signal processing unit ex354 converts it into analog audio signals, so as to output them via the audio output unit ex357. Furthermore, when an e-mail in data communication mode is transmitted, text data of the e-mail inputted by operating the operation keys ex366 and others of the main body is sent out to the main control unit ex360 via the operation input control unit
ex362. The main control unit ex360 causes the modulation/demodulation unit ex352 to perform spread spectrum processing on the text data, and the transmitting and receiving unit ex351 performs the digital-to-analog conversion and the frequency conversion
on the resulting data to transmit the data to the base station ex110 via the antenna ex350. When an e-mail is received, processing that is approximately inverse to the processing for transmitting an e-mail is performed on the received data, and the
resulting data is provided to the display unit ex358.
When video, still images, or video and audio in data communication mode is or are transmitted, the video signal processing unit ex355 compresses and codes video signals supplied from the camera unit ex365 using the moving image coding method
shown in each of Embodiments, and transmits the coded video data to the multiplexing/demultiplexing unit ex353. In contrast, during when the camera unit ex365 captures video, still images, and others, the audio signal processing unit ex354 codes audio
signals collected by the audio input unit ex356, and transmits the coded audio data to the multiplexing/demultiplexing unit ex353.
multiplexing/demultiplexing unit ex353 demultiplexes the multiplexed data into a video data bit stream and an audio data bitstream, and supplies the video signal processing unit ex355 with the coded video data and the audio signal processing unit ex354
with the coded audio data, through the synchronous bus ex370. The video signal processing unit ex355 decodes the video signal using a moving image decoding method corresponding to the moving image coding method shown in each of Embodiments, and then the
display unit ex358 displays, for instance, the video and still images included in the video file linked to the Web page via the LCD control unit ex359. Furthermore, the audio signal processing unit ex354 decodes the audio signal, and the audio output
unit ex357 provides the audio.
Video data can be generated by switching, as necessary, between (i) the moving image coding method or the moving image coding apparatus shown in each of Embodiments and (ii) a moving image coding method or a moving image coding apparatus in
conformity with a different standard, such as MPEG-2, MPEG4-AVC, and VC-1.
the multiplexed data including the video data generated in the moving image coding method and by the moving image coding apparatus shown in each of Embodiments will be hereinafter described. The multiplexed data is a digital stream in the MPEG-2
Transport Stream format.
FIG. 25 illustrates a structure of multiplexed data. As illustrated in FIG. 25, the multiplexed data can be obtained by multiplexing at least one of a video stream, an audio stream, a presentation graphics stream (PG), and an interactive
represents subtitles of a movie. Here, the primary video is normal video to be displayed on a screen, and the secondary video is video to be displayed on a smaller window in the main video. Furthermore, the interactive graphics stream represents an
interactive screen to be generated by arranging the GUI components on a screen. The video stream is coded in the moving image coding method or by the moving image coding apparatus shown in each of Embodiments, or in a moving image coding method or by a
moving image coding apparatus in conformity with a conventional standard, such as MPEG-2, MPEG4-AVC, and VC-1. The audio stream is coded in accordance with a standard, such as Dolby-AC-3, Dolby Digital Plus, MLP, DTS, DTS-HD, and linear PCM.
FIG. 26 schematically illustrates how data is multiplexed. First, a video stream ex235 composed of video frames and an audio stream ex238 composed of audio frames are transformed into a stream of PES packets ex236 and a stream of PES packets
FIG. 27 illustrates how a video stream is stored in a stream of PES packets in more detail. The first bar in FIG. 27 shows a video frame stream in a video stream. The second bar shows the stream of PES packets. As indicated by arrows denoted
as yy1, yy2, yy3, and yy4 in FIG. 27, the video stream is divided into pictures as I pictures, B pictures, and P pictures each of which is a video presentation unit, and the pictures are stored in a payload of each of the PES packets. Each of the PES
FIG. 28 illustrates a format of TS packets to be finally written on the multiplexed data. Each of the TS packets is a 188-byte fixed length packet including a 4-byte TS header having information, such as a PID for identifying a stream and a
packets are written on the multiplexed data. The TP_Extra_Header stores information such as an Arrival_Time_Stamp (ATS). The ATS shows a transfer start time at which each of the TS packets is to be transferred to a PID filter. The numbers incrementing
from the head of the multiplexed data are called source packet numbers (SPNs) as shown at the bottom of FIG. 28.
FIG. 29 illustrates the data structure of the PMT in detail. A PMT header is disposed at the top of the PMT. The PMT header describes the length of data included in the PMT and others. A plurality of descriptors relating to the multiplexed
Each of the multiplexed data information files is management information of the multiplexed data as shown in FIG. 30. The multiplexed data information files are in one to one correspondence with the multiplexed data, and each of the files
As illustrated in FIG. 30, the multiplexed data information includes a system rate, a reproduction start time, and a reproduction end time. The system rate indicates the maximum transfer rate at which a system target decoder to be described
later transfers the multiplexed data to a PID filter. The intervals of the ATSs included in the multiplexed data are set to not higher than a system rate. The reproduction start time indicates a PTS in a video frame at the head of the multiplexed data. An interval of one frame is added to a PTS in a video frame at the end of the multiplexed data, and the PTS is set to the reproduction end time.
As shown in FIG. 31, a piece of attribute information is registered in the stream attribute information, for each PID of each stream included in the multiplexed data. Each piece of attribute information has different information depending on
information is used. More specifically, the moving image coding method or the moving image coding apparatus described in each of Embodiments includes a step or a unit for allocating unique information indicating video data generated by the moving image
coding method or the moving image coding apparatus in each of Embodiments, to the stream type included in the PMT or the video stream attribute information. With the structure, the video data generated by the moving image coding method or the moving
image coding apparatus described in each of Embodiments can be distinguished from video data that conforms to another standard.
Furthermore, FIG. 32 illustrates steps of the moving image decoding method according to Embodiment 5. In Step exS100, the stream type included in the PMT or the video stream attribute information is obtained from the multiplexed data. Next, in
Step exS101, it is determined whether or not the stream type or the video stream attribute information indicates that the multiplexed data is generated by the moving image coding method or the moving image coding apparatus in each of Embodiments. When
it is determined that the stream type or the video stream attribute information indicates that the multiplexed data is generated by the moving image coding method or the moving image coding apparatus in each of Embodiments, in Step exS102, the stream
type or the video stream attribute information is decoded by the moving image decoding method in each of Embodiments. Furthermore, when the stream type or the video stream attribute information indicates conformance to the conventional standards, such
as MPEG-2, MPEG4-AVC, and VC-1, in Step exS103, the stream type or the video stream attribute information is decoded by a moving image decoding method in conformity with the conventional standards.
As such, allocating a new unique value to the stream type or the video stream attribute information enables determination whether or not the moving image decoding method or the moving image decoding apparatus that is described in each of
Embodiments can perform decoding. Even upon an input of multiplexed data that conforms to a different standard, an appropriate decoding method or apparatus can be selected. Thus, it becomes possible to decode information without any error. Furthermore, the moving image coding method or apparatus, or the moving image decoding method or apparatus in Embodiment 5 can be used in the devices and systems described above.
Each of the moving image coding method, the moving image coding apparatus, the moving image decoding method, and the moving image decoding apparatus in each of Embodiments is typically achieved in the form of an integrated circuit or a Large
Scale Integrated (LSI) circuit. As an example of the LSI, FIG. 33 illustrates a configuration of the LSI ex500 that is made into one chip. The LSI ex500 includes elements ex501, ex502, ex503, ex504, ex505, ex506, ex507, ex508, and ex509 to be described
below, and the elements are connected to each other through a bus ex510. The power supply circuit unit ex505 is activated by supplying each of the elements with power when the power supply circuit unit ex505 is turned on.
station ex107, or written on the recording media ex215. When data sets are multiplexed, the data sets should be temporarily stored in the buffer ex508 so that the data sets are synchronized with each other.
When video data is decoded by the moving image coding method or by the moving image coding apparatus described in each of Embodiments, compared to when video data that conforms to a conventional standard, such as MPEG-2, MPEG4-AVC, and VC-1, the
computing amount probably increases. Thus, the LSI ex500 needs to be set to a driving frequency higher than that of the CPU ex502 to be used when video data in conformity with the conventional standard is decoded. However, when the driving frequency is
set higher, there is a problem that the power consumption increases.
In order to solve the problem, the moving image decoding apparatus, such as the television ex300 and the LSI ex500 is configured to determine to which standard the video data conforms, and switch between the driving frequencies according to the
determined standard. FIG. 34 illustrates a configuration ex800 in Embodiment 7. A driving frequency switching unit ex803 sets a driving frequency to a higher driving frequency when video data is generated by the moving image coding method or the moving
image coding apparatus described in each of Embodiments. Then, the driving frequency switching unit ex803 instructs a decoding processing unit ex801 that executes the moving image decoding method described in each of Embodiments to decode the video
data. When the video data conforms to the conventional standard, the driving frequency switching unit ex803 sets a driving frequency to a lower driving frequency than that of the video data generated by the moving image coding method or the moving image
coding apparatus described in each of Embodiments. Then, the driving frequency switching unit ex803 instructs the decoding processing unit ex802 that conforms to the conventional standard to decode the video data.
More specifically, the driving frequency switching unit ex803 includes the CPU ex502 and the driving frequency control unit ex512 in FIG. 33. Here, each of the decoding processing unit ex801 that executes the moving image decoding method
described in each of Embodiments and the decoding processing unit ex802 that conforms to the conventional standard corresponds to the signal processing unit ex507 in FIG. 33. The CPU ex502 determines to which standard the video data conforms. Then, the
driving frequency control unit ex512 determines a driving frequency based on a signal from the CPU ex502. Furthermore, the signal processing unit ex507 decodes the video data based on a signal from the CPU ex502. For example, the identification
external signal. Furthermore, the CPU ex502 selects a driving frequency based on, for example, a look-up table in which the standards of the video data are associated with the driving frequencies as shown in FIG. 36. The driving frequency can be
selected by storing the look-up table in the buffer ex508 and an internal memory of an LSI and with reference to the look-up table by the CPU ex502.
FIG. 35 illustrates steps for executing a method in Embodiment 7. First, in Step exS200, the signal processing unit ex507 obtains identification information from the multiplexed data. Next, in Step exS201, the CPU ex502 determines whether or
not the video data is generated based on the identification information by the coding method and the coding apparatus described in each of Embodiments. When the video data is generated by the coding method and the coding apparatus described in each of
by the coding method and the coding apparatus described in each of Embodiments.
Furthermore, when the computing amount for decoding is larger, the driving frequency may be set higher, and when the computing amount for decoding is smaller, the driving frequency may be set lower as the method for setting the driving
frequency. Thus, the setting method is not limited to the ones described above. For example, when the computing amount for decoding video data in conformity with MPEG4-AVC is larger than the computing amount for decoding video data generated by the
moving image coding method and the moving image coding apparatus described in each of Embodiments, the driving frequency is probably set in reverse order to the setting described above.
Furthermore, the method for setting the driving frequency is not limited to the method for setting the driving frequency lower. For example, when the identification information indicates that the video data is generated by the moving image
coding method and the moving image coding apparatus described in each of Embodiments, the voltage to be applied to the LSI ex500 or the apparatus including the LSI ex500 is probably set higher. When the identification information indicates that the
indicates that the video data is generated by the moving image coding method and the moving image coding apparatus described in each of Embodiments, the driving of the CPU ex502 does not probably have to be suspended. When the identification information
indicates that the video data conforms to the conventional standard, such as MPEG-2, MPEG4-AVC, and VC-1, the driving of the CPU ex502 is probably suspended at a given time because the CPU ex502 has extra processing capacity. Even when the
identification information indicates that the video data is generated by the moving image coding method and the moving image coding apparatus described in each of Embodiments, in the case where the CPU ex502 may have a time delay, the driving of the CPU
ex502 is probably suspended at a given time. In such a case, the suspending time is probably set shorter than that in the case where when the identification information indicates that the video data conforms to the conventional standard, such as MPEG-2,
MPEG4-AVC, and VC-1.
There are cases where a plurality of video data that conforms to different standards, is provided to the devices and systems, such as a television and a cellular phone. In order to enable decoding the plurality of video data that conforms to
the different standards, the signal processing unit ex507 of the LSI ex500 needs to conform to the different standards. However, the problems of increase in the scale of the circuit of the LSI ex500 and increase in the cost arise with the individual use
of the signal processing units ex507 that conform to the respective standards.
In order to solve the problem, what is conceived is a configuration in which the decoding processing unit for implementing the moving image decoding method described in each of Embodiments and the decoding processing unit that conforms to the
conventional standard, such as MPEG-2, MPEG4-AVC, and VC-1 are partly shared. Ex900 in FIG. 37A shows an example of the configuration. For example, the moving image decoding method described in each of Embodiments and the moving image decoding method
that conforms to MPEG4-AVC have, partly in common, the details of processing, such as entropy coding, inverse quantization, deblocking filtering, and motion compensated prediction. The details of processing to be shared probably include use of a
decoding processing unit ex902 that conforms to MPEG4-AVC. In contrast, a dedicated decoding processing unit ex901 is probably used for other processing unique to the present invention. Since the present invention is characterized by the arithmetic
decoding in particular, for example, the dedicated decoding processing unit ex901 is used for the arithmetic decoding. Otherwise, the decoding processing unit is probably shared for one of the inverse quantization, deblocking filtering, and motion
compensation, or all of the processing. The decoding processing unit for implementing the moving image decoding method described in each of Embodiments may be shared for the processing to be shared, and a dedicated decoding processing unit may be used
for processing unique to that of MPEG4-AVC.
Furthermore, ex1000 in FIG. 37B shows another example in which processing is partly shared. This example uses a configuration including a dedicated decoding processing unit ex1001 that supports the processing unique to the present invention, a
dedicated decoding processing unit ex1002 that supports the processing unique to another conventional standard, and a decoding processing unit ex1003 that supports processing to be shared between the moving image decoding method in the present invention
and the conventional moving image decoding method. Here, the dedicated decoding processing units ex1001 and ex1002 are not necessarily specialized for the processing of the present invention and the processing of the conventional standard, and may be
the ones capable of implementing general processing. Furthermore, the configuration of Embodiment 8 can be implemented by the LSI ex500.
As such, reducing the scale of the circuit of an LSI and reducing the cost are possible by sharing the decoding processing unit for the processing to be shared between the moving image decoding method in the present invention and the moving
image decoding method in conformity with the conventional standard.
Although only some exemplary embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially
departing from the novel teachings and advantages of the present invention. Accordingly, all such modifications are intended to be included within the scope of the present invention.
The present invention is applicable to an image coding method, an image decoding method, an image coding apparatus, and an image decoding apparatus, and in particular, is applicable to an image coding method, an image decoding method, an image
coding apparatus, and an image decoding apparatus which use arithmetic coding and arithmetic decoding.
Previous Patent US 9,591,310 | Next Patent US 9,591,312 File A Patent Application Protect your idea -- Don't let