1. MPEG: A Video Compression Standard for Multimedia Applications Didler Le Gall

2. Goals Reduce the high cost of video compression codecs Resolve the critical problem of interoperability of equipment from different manufacturers Come up with a standard within 2 years

3. MPEG Stands for Moving Picture Experts Group (ISO-IEC) Started in 1988 Had to come up with a draft of the standard by 1990 Received MPEG Proposal from mostly commercial companies

4. MPEG (cont’d) MPEG-Video MPEG-Audio MPEG-System –Synchronization of audio and video

5. Requirements A Generic Standard Random Access Fast Forward/Reverse Searches Reverse Playback Audio Visual Synchronization Robustness to Errors

6. Requirements (cont’d) Coding/Decoding Delay Editability Format Flexibility Cost Tradeoffs

7. MPEG-VIDEO Compression Spacial Redundancy –Intraframe compression –DCT compression Temporal Redundancy (i.e. motion compression) –Interframe compression

8. Discrete Cosine Transform (DCT) 120108907569738289 127115978175798895 13412210589838796103 13712510792869099106 13111910186808393100 117105877265697885 10088705549536269 8977594438425158 0 – black 255 – white

9. DCT (cont’d) The 64 (8 x 8) DCT basis functions Superimpose multiples of these functions to simulate the original picture

10. DCT (cont’d) 0 – black 255 – white 7009010000000 900000000 -890000000 00000000 00000000 00000000 00000000 00000000

11. DCT (cont’d) 700 90 90 -89 0 100 0 0 0.... 0 7009010000000 900000000 -890000000 00000000 00000000 00000000 00000000 00000000

12. Motion Compensation I-Frame –Independently reconstructed P-Frame –Forward predicted from the last I- Frame or P-Frame B-Frame –forward predicted and backward predicted from the last/next I-frame or P-frame Transmitted as - I P B B B P B B B

13. Motion Prediction

14. Motion Estimation

15. Motion Estimation (cont’d)

16. Conclusion Video quality better than VHS can be achieved with a bit rate of about 1.5 Mbits/s Does not handle higher resolution with small bit rate

17. References MPEG Notes by Dale Kolosna MPEG Compression Technique (http://rnvs.informatik.tu- chemnitz.de/~jan/MPEG/HTML/mpeg_tech.html)