Systematic lossy error protection of video signals

Systematic Lossy Error Protection (SLEP) is an error-resilient video coding scheme based on the principle of systematic lossy source/channel coding. The systematic transmission consists of a compressed video signal which is sent to the decoder without channel coding. For error resilience, a supplementary bit stream generated by Wyner-Ziv encoding of the video signal is also transmitted. The Wyner-Ziv bit stream allows the decoding of a coarsely quantized redundant description, which can be used in lieu of the lost or error-prone portions of the systematic signal. The resulting error protection scheme is based on a flexible tradeoff between the coarseness (quality) of the redundant video description and the error robustness provided by that description.; We conduct a theoretical analysis of a simplified transmission system in which SLEP is used for robust transmission of samples generated by a first-order Markov source. The source is compressed using a DPCM-style encoder, and a Wyner-Ziv encoded version of the prediction error is transmitted to provide robustness to symbol erasures. Using high-rate quantization theory, we derive a closed-form expression for the overall rate-distortion tradeoff and study the error resilience properties of this simplified SLEP system.; Next, a practical SLEP scheme is presented, in which the Wyner-Ziv bit stream is generated by applying Reed-Solomon codes across H.264/AVC redundant slices. Compared to traditional FEC, SLEP provides graceful degradation of average video quality and reduces the instantaneous quality fluctuation introduced by transmission errors. Additionally, using "Flexible Macroblock Ordering" (FMO), it is possible to provide preferential Wyner-Ziv protection to a region of interest within a video frame.; The picture quality at the receiver of a SLEP system is determined by the rate-distortion tradeoffs of the systematic (primary) and redundant video descriptions, and the Wyner-Ziv bit rate. We derive a model which describes the average received video quality as a function of these three quantities, and use it to study the properties of SLEP. The model closely predicts the results obtained by experimental simulation and is used to find the bit rates for encoding the primary (systematic) and redundant descriptions, and the Wyner-Ziv bit rate such that the received picture quality is maximized.