EXTENSIONS OF ITU-T RECOMMENDATION H.324 FOR ERROR-RESILIENT VIDEO TRANSMISSION

The authors provide an overview of recent techniques that enable the u se of ITU-T Recommendation H.324 with error-prone transmission channel s. H.324 covers the overall architecture, algorithms, and syntax for l ow-bit-rate multimedia terminals. This overview focuses on extensions for error-resilient video transmission that are related to the H.263 v ideo codec and H.223 multiplex. The latter is responsible for reliable delivery of data to each terminal component and is therefore of major importance to the overall system. In particular, the discussed approa ches to robust video transmission require reliable performance of the multiplex scheme. The considered techniques for video coding are eithe r compatible with the baseline mode of H.263 or part of new extensions recently devised by Study Group 16 as part of the H.263+ effort. This overview includes ''Error Tracking'' (Appendix II), ''Reference Pictu re Selection'' (Annex N), and ''Independent Segment Decoding'' (Annex R). Whenever appropriate, the description of those video extensions an d multiplex schemes is complemented with simulation results for transm ission over Rayleigh fading channels.