Error spreading: A perception-driven approach to handling error in continuous media streaming

With the growing popularity of the Internet, there is increasing interest in using it for audio and video transmission. Perceptual studies of audio and video viewing have shown that viewers find bursty losses, mostly caused by congestion, to be the most annoying disturbance, and hence these are critical issues to be addressed for continuous media streaming applications. Classical error handling techniques have mostly been geared toward ensuring that the transmission is correct, with no attention to time-liness. For isochronous traffic like audio and video, timeliness is a key criterion, and given the high degree of content redundancy, some loss of content is quite acceptable. In this paper, we introduce the concept of error spreading, which is a transformation technique that permutes the input sequence of packets (from a continuous stream of data) before transmission. The packets are unscrambled at the receiving end. The transformation is designed to ensure that bursty losses in the transformed domain get spread all over the sequence in the original domain, thus improving the perceptual quality of the stream. Our error spreading idea deals with both cases where the stream has or does not have inter-frame dependencies. We next describe a continuous media transmission protocol and experimentally validate its performance based on this idea. We also show that our protocol can be used complementary to other error handling protocols.