This paper investigates extensions of H.264/AVC for compressing multi-view video sequences. The proposed technique re-sorts frames of sequences captured by multiple cameras looking at a person in a scene from different views and generates a single video sequence. The multi-frame referencing property of the H.264/AVC； which enables exploitation of the spatial and temporal redundancy contained in the multi-view sequences； is employed to implement several modes of operation in the proposed coding algorithm. To evaluate the performance of the proposed coding technique at different modes of operations； five multi-view video sequences at different frame rates were coded using the proposed and the simulcast H.264/AVC coding schemes. Experiments show the superior performance of the proposed coding scheme when coding the multi-view sequences at low and up to half of the original frame rates.

Systems with cheap/simple/power efficient encoders but complex decoders make applications such as low cost, low power remote sensors practical. Bandwidth considerations however are still an issue and compression efficiency has to remain high. In this paper, we present a distributed video codec (DVC) that we are developing with the aim of achieving such a low power paradigm at the cost of only a small compression performance deficit relative to the current state of the art, H.264. The proposed system employs spatial interleaving of KEY and Wyner-Ziv data which allows efficient side information (SI) generation through block-based error concealment, a Gray code that increases the accuracy of bit probability estimation, and a diversity scheme that produces more reliable results by exploiting multiple SI generated data. Simulation results show an improvement of the proposed scheme over H.264 intra coding of up to 1.5 dB. We additionally propose two mechanisms for selective parity bit feedback requests that can further reduce the WZ bitrate by up to 15%.

Perception-oriented video coding based on texture analysis and synthesis has gained importance over the past few years. Hence, the present paper overviews a selection of related approaches that have been proposed over the past decades. They are also referred to as content-based video coding (CBVC) methods in this paper. For better insight into CBVC, an overview on texture analysis and synthesis is also given. Furthermore, the principles common to a careful selection of CBVC methods are depicted and the requirements of each of the fundamental modules are extensively discussed in the context of the limitations of state-of-the-art hybrid video codecs like H.264/AVC.

The latest video coding standard H.264 has been recently approved and has already been adopted for numerous applications including HD-DVD and satellite broadcast. To allow interconnectivity between different applications using H.264, transcoding will be a key factor. When requantizing a bitstream the incoming coding decisions are usually kept unchanged to reduce the complexity, but it can have a major impact on the coding efficiency. This paper proposes a novel algorithm for mode refinement of inter prediction in the case of requantization of H.264 bitstreams. The proposed approach gives a comparable quality to a full search for a fraction of its complexity by exploiting the statistical properties of the mode distribution and motion vector refinement.

This paper presents a concealment based approach to distributed video coding that uses hybrid Key/WZ frames via an FMO type interleaving of macroblocks. Our motivation stems from a previous work of ours that showed promising results relative to the more common approach of splitting the sequence in key and WZ frames. In this paper, we extend our previous scheme to the case of I-B-P frame structures and transform domain DVC. We additionally introduce a number of enhancements at the decoder including use of spatio-temporal concealment for generating the side information on a MB basis, mode selection for switching between the two concealment approaches and for deciding how the correlation noise is estimated, local (MB wise) correlation noise estimation and modified B frame quantisation. The results presented indicate considerable improvement (up to 30%) compared to corresponding frame extrapolation and frame interpolation schemes.

Systems with cheap/simple/power efficient encoders but complex decoders make applications such as low cost, low power remote sensors practical. Bandwidth considerations however are still an issue and compression efficiency has to remain high. In this paper, we present a distributed video codec (DVC) that we are developing with the aim of achieving such a low power paradigm at the cost of only a small compression performance deficit relative to the current state of the art, H.264. The proposed system employs spatial interleaving of KEY and Wyner-Ziv data which allows efficient side information (SI) generation through block-based error concealment, a Gray code that increases the accuracy of bit probability estimation, and a diversity scheme that produces more reliable results by exploiting multiple SI generated data. Simulation results show an improvement of the proposed scheme over H.264 intra coding of up to 1.5 dB. We additionally propose two mechanisms for selective parity bit feedback requests that can fizrther reduce the WZ bitrate by up to 15%.