Following the development of digital communications, focus is now on interactive multimedia services on telephone networks. To provide such applications, verylowbitrate video coding algorithms have to be designed a...
详细信息
ISBN:
(纸本)081941638X
Following the development of digital communications, focus is now on interactive multimedia services on telephone networks. To provide such applications, verylowbitrate video coding algorithms have to be designed and optimized. A standardization process is being started within MPEG under the MPEG-4 denomination, to build a generic scheme for bitrates from 10 to 64 kbit/s. The Laboratories d'Electronique Philips are currently involved in European projects which are devoting their efforts to the elaboration of a common European proposal towards MPEG-4. This paper gives an overview of the research status on verylowbitrate video coding within Philips and within Europe. Most of the European studies are concerned with region based compression technique; emphasis will therefore be put on the two major algorithms enhancing this technique.
We propose a balanced multiple description coding framework using rate-distortion splitting for three dimensional DCT (3D DCT) coded video data. The proposed algorithm produces correlated and balanced descriptions, wi...
详细信息
We propose a balanced multiple description coding framework using rate-distortion splitting for three dimensional DCT (3D DCT) coded video data. The proposed algorithm produces correlated and balanced descriptions, with balancing in terms of bitrate and receiver distortion. Our description splitting and balancing algorithm takes advantage of the structural properties of the 3D DCT video volume and the method of shifted compliment hyperboloid used in scanning and quantization of 3D DCT coefficients. Given the available bitrate and redundancy our simulations show high PSNR values for the reconstructed video. The proposed video codec requires a simple implementation, has a low complexity, and produces a high reconstruction quality. Comparative results with other schemes are included.
In this paper, we present a novel design of a wavelet-based video coding algorithm within a conventional hybrid framework of temporal motion-compensated prediction and transform coding. Our proposed algorithm involves...
详细信息
ISBN:
(纸本)0819444111
In this paper, we present a novel design of a wavelet-based video coding algorithm within a conventional hybrid framework of temporal motion-compensated prediction and transform coding. Our proposed algorithm involves the incorporation of multi-frame motion compensation as an effective means of improving the quality of the temporal prediction. In addition, we follow the rate-distortion optimizing strategy of using a Lagrangian cost function to discriminate between different decisions in the video encoding process. Finally, we demonstrate that context-based adaptive arithmetic coding is a key element for fast adaptation and high coding efficiency. The combination of overlapped block motion compensation and frame-based transform coding enables blocking-artifact free and hence subjectively more pleasing video. In comparison with a highly optimized MPEG-4 Advanced Simple Profile coder, our proposed scheme provides significant performance gains in objective quality of 2.0-3.5 dB PSNR.
Model-based coding is a new image sequence compression technique for very low bit rate coding. Most researchers have paid more attention to facial image analysis and synthesis because facial images are very important ...
详细信息
Model-based coding is a new image sequence compression technique for very low bit rate coding. Most researchers have paid more attention to facial image analysis and synthesis because facial images are very important in multimedia communication applications, such as video phone, video conferencing, remote learning etc. This coding method represents the image content in a structural way. This is the reason why model-based coding can get a higher compression ratio (1-10 kb/s) than can the conventional coding methods. In order to encode image signals efficiently, it is necessary to create a suitable generic model and adapt it to the actual object accurately. In this paper, we propose a scheme, based on the integral-projection algorithm, which adapts a face model to an actual face automatically. First, the image is preprocessed by means of edge detection. From the edge mapped image, we use the feature of the increasing sudden edge density to indicate the rough vertical positions of eyes and mouth. According to the local threshold value in each feature area, all of the control points about the eyes and mouth are found. Finally, we use these control points to adapt the model to an actual face.
暂无评论