The quality of a stream can be expected to be roughly proportional to data rate sustained by the receiver.
In general, this implies that in lossy networks the quality of a media stream is not proportional to the amount of correctly received data.
The vast majority of state-of-the art codecs uses single description (SD) video coding.
The reasons are probably the comparingly high complexity of codec development, the loss of some compression efficiency as well as the caused transmission overhead.
Though MDC has its practical roots in media communication, it is widely researched in the area of information theory.