Signal-to-noise ratio (snr) scalability has been incorporated into the MPEG-2 video-coding standard to allow for the delivery of two services with the same spatial and temporal resolution but different levels of quali...
详细信息
Signal-to-noise ratio (snr) scalability has been incorporated into the MPEG-2 video-coding standard to allow for the delivery of two services with the same spatial and temporal resolution but different levels of quality. scalable video coding has many advantages, such as its capability of coping with bandwidth variations, high flexibility and so on. However, few accurate rate control schemes for enhancement layer coding have been proposed. In this paper, we will present a novel enhancement layer rate control scheme for MPEG-2 snrscalable video coding. First, we will address the current necessity and problem of rate control for layered coding. Then through analyzing characteristics of compressed data in the enhancement layer, we will derive our rate control model. The proposed rate control model is applied to a drift-free snrscalable encoder and we show that it performs well for coding of the enhancementlayer bitstream. (c) 2004 Elsevier Inc. All rights reserved.
A flexible and effective macroblock-based framework for hybrid spatial and fine-grain snrscalable video coding is proposed in this paper. In the proposed framework, the base layer is of low resolution and is generall...
详细信息
ISBN:
(纸本)0819444111
A flexible and effective macroblock-based framework for hybrid spatial and fine-grain snrscalable video coding is proposed in this paper. In the proposed framework, the base layer is of low resolution and is generally encoded at low bit rates with traditional prediction based coding schemes. Two enhancement layers, i.e., the low-resolution enhancement layer and the high-resolution enhancement layer, are generated to improve the video quality of the low-resolution base layer and evolve smoothly from low resolution to high resolution video with increasingly better quality, respectively. Since bit plane coding and drifting control techniques are applied to the two enhancement layers, each enhancement bitstream is fine-grain scalable and can be arbitrarily truncated to fit in the available channel bandwidth. In order to improve the coding efficiency and reduce the drifting errors at the high-resolution enhancement layer, five macroblock coding modes with different forms of motion compensation and reconstruction, are proposed in this paper. Furthermore, a mode decision algorithm is developed to select the appropriate coding mode for each macroblock at the high-resolution enhancement layer. Compared with the traditional spatial scalablecoding scheme, the proposed framework not only provides the spatial scalability but also provides the fine granularity quality scalability at the same resolution.
We present a hybrid scalable video coding algorithm in which two types of scalabilities, i.e., layered scalability and parallel scalability, are combined to achieve higher order of flexibility for heterogeneous networ...
详细信息
ISBN:
(纸本)0819461172
We present a hybrid scalable video coding algorithm in which two types of scalabilities, i.e., layered scalability and parallel scalability, are combined to achieve higher order of flexibility for heterogeneous networks and mixed client requirements. In space domain, snrscalable video coding is used to give layered scalability on frame quality;while in temporal domain, a multiple description approach, the Multiple State Video coding (MSVC), provides parallel scalability to the base layer video. Two coarsely quantized sub-streams are yielded using MSVC and form the base layer. All residual signals of the video sequence are coded into a third sub-stream and form the enhancement layer. The hybrid scalable video protects the base layer using multiple description and has better performance than conventional layered scalable video when a base layer picture is damaged. It gives similar performance as snrscalable video when the enhancement layer encounters errors. In general packet drop networks, the proposed scalable video achieves higher Psnr than the original MSVC video and single description video in high packet drop rate environments.
暂无评论