1. A Concealment Method for Shape Information in MPEG-4 Coded Video Sequences Shahram Shirani, Berna Erol, and Faouzi Kossentini IEEE TRANSACTIONS ON MULTIMEDIA, VOL. 2, NO. 3, SEPTEMPER 2000

2. Outline n introduction n MPEG-4: video compression and error resilience n concealment of channel errors in MPEG-4 coded video n proposed method n experimental results

3. Introduction

4. MPEG-4 : Video Compression and Error Resilience n MPEG-4 offers error resilience tools: –video packetization –data partition –reversible VLC

5. MPEG-4 : Error Resilience n video packetization –The macroblock data between two resynchronization markers is referred to as a video packet. n data partition n I-VOPs n n P-VOPs n reversible VLC

6. Concealment of Channel Errors in MPEG-4 Coded Video Data n P-VOPs n I-VOPs

7. Proposed method

8. n The boundary transform: –if all the four neighboring pixels of a pixel are inside the shape, then the pixel is declared inside. Otherwise, the pixel is assigned to the border of the shape.

9. Experimental Results The similarity of the erroneous and error concealed shape data to the original shape data is measures using the following ratio: –n d : the number of pixels that are different between the restored shape and the original one –n t : the total number of pixels in the bounding box

10. Experimental Results (AKIYO) 272x208 30% missing 88% 99% (Mp-Mm)/M = 17%

11. Experimental Results (BREAM) 144x192 29% missing 81% (Mp-Mm)/M 98% = 22%

12. Experimental Results (BREAM) 272x192 25% missing 86% 99%

13. Experimental Results (WEATHER) 160x224 35% missing 87% 99%

14. Conclusions n The paper presents an error concealment method for shape information in the MPEG-4 coded video sequences. n The proposed concealment method successfully reconstructs the missing shape data providing about 20% improvement compared to median filtering method. n Reasonable computational complexity of our algorithm makes it suitable for real-time application.