Robust MPEG-2 SNR scalable coding using variable end-of-block

Signal-to-noise ratio (SNR) scalable coding over priority networks has been used as a robust mechanism to transmission errors, since the most important information (base layer) can be sent over an error free channel as in the case of ATM networks or over protected channel as in the case of IP networks. SNR scalability ensures a minimum video quality at the receiver end by sacrificing the least important information (enhancement layer) when losses occur. However, one disadvantage of scalable coding is its lower compression performance with respect to the one-layer encoding (∼10-15%, (D. Wilson and M. Ghanbari, 1999)). In this work, we propose an error resilient scheme for MPEG-2 SNR scalable video transmission that is compression efficient, in addition to providing scalable error resynchronization mechanism to enhancement layer that impedes the propagation of errors beyond the physically affected area in the bitstream. In order to provide robustness to errors during transmission, the proposed scheme uses triangular coding in the transform domain (R. Hasimoto-Beltran et al., 2000) and a modified variable end of block based on the number of bits per unit of block. Our scheme yields significantly better compression ratios compared to the MPEG-2 standard (3% to 6.7%) while at the same time improves considerably the quality of the received data (2-11 db) under different conditions of data losses.