Performance of Wyner-Ziv video codec under Rayleigh fading channel
James, Geno George
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In this thesis, we analyze the performance of a Wyner-Ziv codec over a flat-fading Rayleigh channel. In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv Theorem on source coding with side information available only at the decoder suggests that an asymmetric video codec, where individual frames are encoded separately, but decoded conditionally (given temporally adjacent frames) could achieve similar efficiency. A transformdomain Wyner-Ziv coding scheme for motion video that uses intraframe encoding, but interframe decoding is implemented. In this system, the transform coefficients of a Wyner-Ziv frame are encoded independently using a scalar quantizer and turbo coder. The decoder uses previously reconstructed frames to generate side information to conditionally decode the Wyner-Ziv frames. In this work, the video is encoded using the Wyner-Ziv video codec that is implemented. The key(even) frames are compressed using a standard H.263 intra-frame encoder and the Wyner-Ziv(odd) frames are coded using Wyner-Ziv coding. Since Wyner-Ziv ceodec acts as a combined source channel coder there is no further channel coding performed on this bitstream. But, the H.263 compressed key frames are protected using RCPC codes. The compressed video is simulated over a flat-fading Rayleigh channel with Additive White Gaussian Noise(AWGN). The experimental results show that Wynwr-Ziv codec performs better than pure intra coding under channel noise and also they offer impressive bitrate savings.