Research On Video Error Concealment Based On No-Waiting ARQ For JVT Video Standard

Loss of information during transmission of compressed video over error prone networks may lead to objectionable visual distortion in the decoded video, and such distortion can propagate to many frames because of the motion compensated prediction and the variable-length coding used. As the solution to this serious problem, video error recovery and concealment techniques thus play a key role and attract more and more attentions in current video compression and communication. In this paper, research on such video error recovery and concealment techniques as decoder-side error concealment (EC) and feedback-based retransmission without waiting (NWARQ) is carried out based on the test modal reference software JM1.4 of the developing ISO/IEC MPEG and ITU-T VCEG video coding standard JVT (Joint Video Team).In chapter 1 a brief introduction to problems resulting from video compression and transmission and solutions to the stated problems is addressed. Detailed descriptions of JM1.4's newly adopted algorithms are presented in chapter 2. Chapter 3 discusses various video error recovery and concealment techniques, including error resilient encoding schemes, receiver-side post-processing and several feedback-based error control techniques, etc. Knowledge in these chapters forms the theoretical basis of our research.In chapter 4 the emphasis of our research is mainly concentrated on EC technique. Several theoretically useful improvements over current EC techniques' deficiencies are introduced, such as Side Matching, Preprocessing and Motion Vector Extrapolation, and Search at Decoder Side is proposed. All methods presented in this chapter are implemented and tested based on modified JM1.4 codec of JVT. Simulation results show that both objective gains measured in PSNR (peak signal-to-noise ratio) and visual improvements of reconstructed video can be achieved by utilizing introduced methods.Chapter 5 gives the implementation of JVT-based NWARQ technique. Simulation results based on modified JM1.4 codec show that implemented NWARQ can stop error propagation at decoder and completely recover damaged video without introducing any additional playout delay, comparing to EC and conventional ARQ (automatic repeat request) technique.