a concealment method for shape information in mpeg-4 coded video sequences shahram shirani, berna...

A Concealment Method for Shape Information in MPEG-4 Coded Video Sequences

Shahram Shirani, Berna Erol, and Faouzi KossentiniIEEE TRANSACTIONS ON MULTIMEDIA, VOL. 2, NO. 3, SEPTEMPER 2000

Outline

introduction MPEG-4: video compression and error

resilience concealment of channel errors in

MPEG-4 coded video proposed method experimental results

Introduction

MPEG-4 : Video Compression and Error Resilience

MPEG-4 offers error resilience tools:– video packetization– data partition– reversible VLC

MPEG-4 : Error Resilience

video packetization– The macroblock data between two resynchronization

markers is referred to as a video packet. data partition I-VOPs P-VOPs

reversible VLC

Concealment of Channel Errors in MPEG-4 Coded Video Data

P-VOPs

I-VOPs

Proposed method

Proposed method

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.

Experimental Results

The similarity of the erroneous and error concealed shape data to the original shape data is measures using the following ratio:

– nd : the number of pixels that are different between the restored shape and the original one

– nt : the total number of pixels in the bounding box

Experimental Results (AKIYO)

272x208 30% missing

88%

99% (Mp-Mm)/M

= 17%

Experimental Results (BREAM)

144x192 29% missing

81%

(Mp-Mm)/M

98% = 22%

Experimental Results (BREAM)

272x192

25% missing

86%

99%

Experimental Results (WEATHER)

160x224

35% missing

87%

99%

Conclusions

The paper presents an error concealment method for shape information in the MPEG-4 coded video sequences.

The proposed concealment method successfully reconstructs the missing shape data providing about 20% improvement compared to median filtering method.

Reasonable computational complexity of our algorithm makes it suitable for real-time application.