Error-resilient video transcoding for robust internetwork communications using GPRS

A novel fully comprehensive mobile video communications system is proposed. The system exploits the useful rate management features of video transcoders and combines them with error resilience for the transmission of coded video streams over general packet radio service (GPRS) mobile-access networks. The error-resilient video transcoding operation takes place at a centralized point, referred to as a video proxy, which provides the necessary output transmission rates with the required amount of robustness. With the use of this proposed algorithm, error resilience can be added to an already compressed video stream at an intermediate stage at the edge of two or more different networks through two resilience schemes, namely the adaptive intra refresh (AIR) and feedback control signaling (FCS) methods. Both resilience tools impose an output rate increase which can also be prevented with the proposed novel technique. Thus, the presented scheme gives robust video outputs at near target transmission rates that only require the same number of GPRS timeslots as non-resilient schemes. Moreover, an ultimate robustness is also accomplished with the combination of the two resilience algorithms at the video proxy. Extensive computer simulations demonstrate the effectiveness of the proposed system.