1. MPEG Motion Picture Expert Group Moving Picture Encoded Group Prateek raj gautam(725/09)

2. MPEG-1 Optimized for bitrates around 1.5 Mbit/s mainly designed for error-free digital storage media multiplexing of audio, video and data 352x240 pixels a 30 frames/sec [ NTSC based ] 352x288 pixels at 25 frames/sec [ PAL based ] Applications CD, digital multimedia, and video database (e.g. video-on-demand)

3. MPEG-2 2-15 or 16-80 Mbit/s bit rate Applications: satellite, cable, and terrestrial broadcasting, digital networks, and digital VCR

4. Basics of MPEG Types of pictures frames I (intra) frame compressed using only intraframe coding Moderate compression but faster random access P (predicted) frame Coded with motion compression using past I frames or P frames Can be used as reference pictures for additional motion compensation B (bidirectional) frame Coded by motion compensation by either past or future I or P frames D (DC) frame Limited use: encodes only DC components of intraframe coding

5. FRAME SEQUENCE

6. MPEG Compression is Based on Processing 8 x 8 Pixel Blocks

7. Only Moving Areas Have to Be Coded

8. MOTION VECTOR

9. Try to match each block in the actual picture to content in the previous picture. Matching is made by shifting each of the 8 x 8 blocks of the Two successive pictures pixel by pixel each direction - > Motion vector Substract the two blocks -> Difference block Transmit the motion vector and the difference block

10. MPEG: Video Encoding Pre processing Frame Memory + - DCT Motion Compensation Motion Estimation Frame Memory + IDCT Quantizer (Q) Regulator VLC Encoder Buffer Q -1 Output Input Predictive frame Motion vectors

11. MPEG-2 Why another standard?  Support higher bit rates e.g., 80-100 Mbits/s for HDTV instead of the 1.15 Mvits/s for SIF  Support a larger number of applications  The encoding standard should be a toolkit rather than a flat procedure Interlaced and non-interlaced frame Different color subsampling modes e.g., 4:2:2, 4:2:0, 4:4:4 Flexible quantization schemes – can be changed at picture level Scalable bit-streams Profiles and levels

12. THANK YOU