Scalable Rate Control Research Articles

An integrated rate control scheme for TCP-friendly MPEG-4 video transmission

Delivering MPEG-4 real-time video over the Internet requires the use of rate control schemes in both the compression and the transport domains. This paper discusses the practical difficulties involved in integrating MPEG-4 scalable rate control (SRC) in the compression domain with TCP-friendly rate control (TFRC) in the transport domain. In addition to the requirement for rate matching between the two schemes to ensure TCP-friendliness, users demand a high-quality, smooth media output under the varying network conditions. In this paper, an integrated rate control scheme is proposed for MPEG-4 video transported by a TFRC protocol. The proposed scheme comprises a rate smoothing control mechanism to meet the rate matching with the controlled transmission buffering delay, and an adaptive rate control for the I-frame designed to reduce the frame skipping. Through the successful integration of the two schemes, the experimental results show that the proposed scheme better preserves the motion smoothness and improves the overall perceptual quality for TCP-friendly MPEG-4 video transmissions to obtain a smooth, high visual quality video experience.

Scalable rate control for video transmission over UMTS

AbstractThis paper proposes a mechanism for the congestion control for video transmission over Universal Mobile Telecommunications System (UMTS). Our scheme is applied when the mobile user experiences real time multimedia content and adopts the theory of a widely accepted rate control method in wired networks, namely equation‐based rate control. In this approach, the transmission rate of the multimedia data is determined as a function of the packet loss rate, the round trip time and the packet size and the server explicitly adjusts its sending rate as a function of these parameters. Through a number of simulations and experiments we validate the correctness and measure the performance and efficiency of the mechanism. A first level of evaluation is carried out using the ns‐2 simulator. A second level then validates the proposed mechanism in real world traffic scenarios by performing experiments in a commercial UMTS network. Copyright © 2006 John Wiley & Sons, Ltd.

Scalable rate control for MPEG-4 video

This paper presents a scalable rate control (SRC) scheme based on a more accurate second-order rate-distortion model. A sliding-window method for data selection is used to mitigate the impact of a scene change. The data points for updating a model are adaptively selected such that the statistical behavior is improved. For video object (VO) shape coding, we use an adaptive threshold method to remove shape-coding artifacts for MPEG-4 applications. A dynamic bit allocation among VOs is implemented according to the coding complexities for each VO. SRC achieves more accurate bit allocation with low latency and limited buffer size. In a single framework, SRC offers multiple layers of controls for objects, frames, and macroblocks (MBs). At MB level, SRC provides finer bit rate and buffer control. At multiple VO level, SRC offers superior VO presentation for multimedia applications. The proposed SRC scheme has been adopted as part of the International Standard of the emerging ISO MPEG-4 standard.