Distributed video coding (DVC) is a new video coding paradigm based on two key Information Theory results: the Slepian-Wolf and Wyner-Ziv theorems. A particular case of DVC, the so-called Wyner-Ziv coding, deals with lossy source coding with side information at the decoder and enables a flexible allocation of complexity between the encoder and the decoder. This paper proposes an improved transform domain Wyner-Ziv video codec including: 1) the integer block-based transform defined in the H.264/MPEG-4 AVC standard, 2) a quantizer with a symmetrical interval around zero for AC coefficients, and a quantization step size adjusted to the transform coefficient bands dynamic range, and finally and 3) advanced frame interpolation for side information generation. The combination of these tools brings significant rate-distortion (RD) gains regarding the state-of-the-art results available in the literature.

In distributed video coding (DVC), the video statistics are exploited, partially or totally at the decoder. A particular case of DVC, WynerZiv video coding deals with lossy source coding with side information at the decoder and allows moving part or the entire motion estimation task to the decoder. In this context, it is the decoder responsibility to obtain the side information, a guess of the encoded Wyner-Ziv frame and the encoder only sends parity bits to improve its quality. In this paper, a technique targeting the improvement of the quality of the side information, and thus of the rate-distortion performance of the Wyner-Ziv codec is proposed. This is achieved by adaptively adjusting the size of the motion interpolation structure (or GOP length) according to the motion activity along the sequence. Experimentally, this allows to achieve gains up to 0.8 dB without performing any motion estimation or complex mode decision at the encoder.

Distributed video coding (DVC) is a new coding

Wyner-Ziv (WZ) video coding -a particular case of distributed video coding (DVC) -is a new video coding paradigm based on two major Information Theory results: the Slepian-Wolf and Wyner-Ziv theorems. Recently, practical WZ video coding solutions were proposed with promising results. Most of the solutions available in the literature, model the correlation noise between the original frame and the so-called side information by a given distribution whose relevant parameters are estimated in an offline process, at the encoder. In this paper, three algorithms are proposed towards a more realistic WZ coding approach by performing online estimation of the error distribution at the decoder. Both algorithms explore temporal correlation between frames however with different levels of granularity: frame, block and pixel levels; better rate-distortion (RD) performance is achieved for lower granularity (pixel) level.