The transmission of multimedia data over bandwidth-limited and error-prone channels has imposed to reconsider Shannon's separation principle that recommended independant design of the source coding (compression) and channel coding (protection) operations. Still, to allow for compatibility with existing standards, and deployment on existing architectures where network layers can be present between the source and channel coders, an integration into a unique joint coder is not considered here, and the compression and protection are kept apart, albeit in cooperation.

Joint source and channel coding ensures that the impact of errors, almost unavoidable in wireless channels, is taken into account by to combining efficiently compression and protection from the rendering point of view. As a matter of fact, the classical source rate control algorithms proposed in the absence of transmission errors such as rely on the assumption that Forward Error Correction (FEC) tools let the packets arrive error free at the video decoder. While of particular interest for wired transmissions and broadcasting, these solutions do not take into account either the potentially important distortion effects introduced by a residual bit error probability unavoidable in low-bandwidth transmissions or the different sensitivities of the bitstream.