Improvements of video coding over wireless channel and analysis of error probability and rate control

Conventional video coding schemes such as H.261/H.263 have reduced performances over a wireless link. In this paper, two methods are proposed to increase video coding performances over a wireless link. The first method is based on the dynamic working set of motion vectors. It detects and recovers errors occurring in motion vector fields. The second method improves performances by changing the video coding granularity to the macro block level. An implementation scheme for the second method is presented. The constraints that rate control imposes on the discard threshold are discussed and the corresponding performance model is provided.