In its original formulation, multiple description (MD) coding is a multiuser lossy  source coding problem, in which three decoders get to observe encodings of a single  source generated by two senders. In general, the rate delivered to each of the  decoders is not the same, and based on this it has been argued that MD codes  would be suitable for use as joint source/channel codes in a standard point-topoint  problem: low-rate decoders would be used when there is loss of data, and  high-rate decoders would be used when more data is available at the receiver