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H.264/AVC

H.264/AVC. ITU-T Standard. Joint ITU-T/MPEG Standards. H.262/MPEG-2. H.264/MPEG-4 AVC. MPEG Standard. H.261 (Version 1). MPEG-1. H.261 (Version 2). MPEG-4 (Version 1). H.263. H.263+. H.263++. MPEG-4 (Version 2). 1988. 1990. 1992. 1994. 1996. 1998. 2000. 2002. 2004.

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H.264/AVC

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  1. H.264/AVC

  2. ITU-T Standard Joint ITU-T/MPEG Standards H.262/MPEG-2 H.264/MPEG-4 AVC MPEG Standard H.261 (Version 1) MPEG-1 H.261 (Version 2) MPEG-4 (Version 1) H.263 H.263+ H.263++ MPEG-4 (Version 2) 1988 1990 1992 1994 1996 1998 2000 2002 2004 Evolution of Video coding Standards

  3. Applications • Entertainment Video (1-8+ Mbps, higher latency) • Broadcast / Satellite / Cable / DVD / VoD/ FS-VDSL / … • DVB/ATSC/SCTE, DVD Forum, DSL Forum • Conversational Services (usu. <1Mbps, low latency) • H.320 Conversational • 3GPP Conversational H.324/M • H.323 Conversational Internet/best effort IP/RTP • 3GPP Conversational IP/RTP/SIP • Streaming Services (usu. lower bit rate, higher latency) • 3GPP Streaming IP/RTP/RTSP • Streaming IP/RTP/RTSP (without TCP fallback) • Other Services • 3GPP Multimedia Messaging Services

  4. Structure of H.264/AVC video encoder Control Data Video Coding Layer Coded Macroblock Data Partitioning Coded Slice/Partition Network Abstraction Layer H.320 MP4FF H.323/IP MPEG-2 etc.

  5. High-Level VCL Summary • Some new key aspects are: • Enhanced motion compensation • Small blocks for transform coding • Improved de-blocking filter • Enhanced entropy coding • Substantial bit-rate savings relative to other standards for the same quality

  6. Macroblocks and Slices • Macroblocks: 16x16 luma + 8x8 for chroma samples • Slice: a set of MBs that can be decoded without use of other slices • I slice: intra-prediction (I-MBs) • P slice: possibly one inter-prediction signal (I- and P-MBs) • B slice: up to two inter-prediction signals (I- and B-MBs) • SP slice: P slice to facilitate switching between coded streams • SI slice: I slice to to facilitate switching between coded streams

  7. Enhanced MC (Inter Prediction) • Every macroblock can be split in one of 7 ways for improved motion estimation

  8. Enhanced MC (Inter Prediction) • Accuracy of motion compensation = 1/4 pixel • Up to 5 reference frames for SDTV size @ L3 • Reference B pictures • Weighted predictions • Motion Estimation을수행하는신호에적응적으로가중치를주어계산한후예측신호를생성

  9. Intra Spatial Prediction using surrounding available samples Intra 4x4 Prediction Modes • 4 modes for 16x16 intra prediction Intra 16x16 Prediction Modes

  10. Transform • MBs are divided up into 4x4 or 8x8 blocks • Transformation matrix T4x4 or T8x8 is applied to residual data of every block • For the DC Coefficients, • Hadamard transform H4x4 for the 4×4 array of luma DC coefficients in Intra MBs predicted in 16×16 mode. • Hadamard transform H2x2 for the 2 × 2 array of chroma DC coefficients (in any macroblock).

  11. Quantization • Logarithmic step size control • A total of 52 values of Qstep are supported by the standard, indexed by a Quantization Parameter, QP. • Qstep doubles in size for every increment of 6 in QP. • Can change to any step size at macroblock level • Quantization reconstruction is one multiply, one add, one shift

  12. Adaptive Deblocking Filter • Blocking artifacts • 4*4 transforms and block-based motion compensation • Block edges are typically reconstructed with less accuracy than interior pixels. • Improve subjective and objective quality of the decoded picture • Result in bit rate savings of around 6~9% Reconstructed, QP=36 (no filter) Original Frame Reconstructed, QP=36 (with filter)

  13. Entropy Coding • CAVLC (Context Adaptive Variable Length Coding) • Context : already coded information of the neighboring blocks and the coding status of the current block • Optimized VLC tables are provided for each context to code the coefficients in different statistical conditions • CABAC (Context Adaptive Binary Arithmetic Codes) • Use a binary arithmetic coding engine • Compression improvement is consequence of • Adaptive probability estimation • Improved context modeling scheme • Exploiting symbol correlations by using contexts • Average bit-rate saving over CAVLC 5~15%

  14. Error Resilience Tools • Flexible Macroblock Order (FMO) • Arbitrary Slide Order (ASO) • Redundant Slice (RS) • Data Partitioning (DP)

  15. MB to Slice Group Mappings • Flexible Macroblock Ordering (FMO) • a subset of the macroblocks may contain one or more slices • Application example: Error resilience

  16. Arbitrary Slice Ordering (ASO) • The decoding order of the slices could be arbitrary • Application example: reduce end-end transmission delay in RT app

  17. H.264/AVC의해상도의크기

  18. Profiles

  19. Basic Coding Structure

  20. Comparison to Previous Standards • The set of test sequences for this comparison consists of • four QCIF (10 and 15 Hz) sequence • 176 x144 resolution at 10–256 kb/s • four CIF (15 Hz and 30 Hz) sequence • CIF 352 x 288 resolution at 128–1024 kb/s

  21. Comparision of Standards

  22. Comparision of Standards (cont’d..)

  23. References • Related group MPEG website http://www.mpeg.org JVT website: ftp://ftp.imtc-files.org/jvt-experts www.mpegif.org • Test software H.264/AVC JM Software: http://bs.hhi.de/~suehring/tml/download • Test sequences http://ise.stanford.edu/video.html http://kbs.cs.tu-berlin.de/~stewe/vceg/sequences.htm http://www.its.bldrdoc.gov/vqeg ftp.tnt.uni-hannover.de/pub/jvt/sequences/ http://trace.eas.asu.edu/yuv/yuv.html • Papers Wiegand, T.; Sullivan, G.J.; Bjontegaard, G.; Luthra, A., “Overview of the H.264/AVC Video Coding Standard,” in IEEE transactions on circuits and systems for video technology, Vol. 12, No.7, July. 2003. Sullivan, G.J.; Wiegand, T., "Video Compression - From Concepts to the H.264/AVC Standard," Proceedings of the IEEE , vol.93, no.1, pp.18-31, Jan. 2005 Jorn Ostermann et al., “Video coding with H.264/AVC: Tools, Performance, and Complexity,” in IEEE Circuit and systems magazine, first quarter. 2004. M. Mahdi Ghandi and Mohammad Ghanbari, “The H.264/AVC Video Coding Standard for the Next Generation Multimedia Communication,” in IAEEE Journal

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