1. -1/20- MPEG 4, H.264 Compression Standards Presented by Dukhyun Chang (dhchang@mmlab.snu.ac.kr)

2. -2/20- Contents Introduction Features of the H.264/AVC Profile & performance of H.264/AVC Conclusion

3. -3/20- Evolution of Video coding Standards ITU-T Standard Joint ITU-T/MPEG Standards MPEG Standard 198819901992199419961998200020022004 H.261 (Version 1) H.261 (Version 2) H.263H.263+H.263++ H.262/MPEG-2H.264/MPEG-4 AVC MPEG-1 MPEG-4 (Version 1) MPEG-4 (Version 2)

4. -4/20- Structure of H.264/AVC video encoder Control Data Video Coding Layer Data Partitioning Network Abstraction Layer H.323/IPMPEG-2etc.H.320MP4FF Coded Macroblock Coded Slice/Partition

5. -5/20- Applications Broadcast Streaming Content Server Internet Link Mobile Communication Storage DMB Multimedia Service VCL NAL Mpeg-2 systems RTP payload ISO media file format encapsulation H.320, H.324/M NAL gives VCL network independent interface

6. -6/20- Data Structure of MPEG GOP SH IBBPBBP……BBBP slice MB …. Y1 Y3 Y2 Y4 CbCr Sequence GOP Picture Slice Macroblock

7. -7/20- Contents Introduction Features of the H.264/AVC Profile & Performance of H.264/AVC Conclusion

8. -8/20- Basic coding structure of H.264/AVC for a macroblock Entropy Coding Scaling & Inv. Transform Motion- Compensation Control Data Quant. Transf. coeffs Motion Data Intra/Inter Coder Control Decoder Motion Estimation Transform/ Scal./Quant. - Input Video Signal Split into Macroblocks 16x16 pixels Intra-frame Prediction De-blocking Filter Output Video Signal New features of H.264

9. -9/20- Transform MPEG-4 AVC MPEG-2 / MPEG-4 Integer Transform Incoming 4x4 Block transformed 4x4 Block DCT Transform Incoming 8x8 Block transformed 8x8 Block

10. -10/20- Intra & Inter Coding Structure Intra Coding Structure – Intra Frame  Motion estimation cannot be exploited Eliminate spatial redundancy – Directional spatial prediction Motion Compensation – Various block sizes and shapes for motion compensation More precise compensation

11. -11/20- Motion Compensation Multiple reference pictures – Arbitrary weights – Regardless of the temporal direction – Can use B-Slice as reference

12. -12/20- Adaptive Deblocking Filter Deblocking Filter – There are severe blocking artifacts 4*4 transforms and block-based motion compensation – Result in bit rate savings of around 6~9% – Improve subjective quality and PSNR of the decoded picture Without FilterWith AVC Deblocking Filter

13. -13/20- FMO (1/2) FMO (Flexible Macroblock Ordering) – Slice (composed in FMO)  Enhance Robustness to data loss Picture Slice Group Slice …..…. Independently- decodable

14. -14/20- FMO (2/2) Slice #0 Slice #1 Slice #2 Subdivision of a picture into slices when not using FMO Slice Group #0 Slice Group #1 Slice Group #2 Subdivision of a QCIF frame into slices when utilizing FMO Slice Group #0 Slice Group #1

15. -15/20- ASO ASO (Arbitrary Slice Ordering) – Independently-decoded Slice Enables sending and receiving the slice in any order Improve end-to-end delay in real-time application Picture Internet protocol network Slice Start to decode

16. -16/20- 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%

17. -17/20- Profiles

18. -18/20- Comparison to Previous Standards

19. -19/20- Conclusion H.264 is the standard of both ITU-T VCEG and ISO/IEC MPEG gains in compression efficiency of up to 50% compared to previous standards New key features are: – Enhanced motion compensation – Small blocks for transform coding – Integer transform – Improved deblocking filter – Enhanced entropy coding Increased complexity relative to prior standards

20. -20/20- References Ralf Schafer, Thomas Wiegand and Heiko Schwarz, “The emerging H.264/AVC standard,” in EBU technical review, Jan. 2003. Jorn Ostermann et al., “Video coding with H.264/AVC: Tools, Performance, and Complexity,” in IEEE Circuit and systems magazine, first quarter. 2004. Thomas Wiegand et al., “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. M. Mahdi Ghandi and Mohammad Ghanbari, “The H.264/AVC Video Coding Standard for the Next Generation Multimedia Communication,” in IAEEE Jounal.