The loss-jitter Based Adjustment for Multimedia Applications

• Main Authors: Yi-Chia Chiang, 姜怡佳
• Other Authors: Hsiao-Kuang Wu
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/47557795452478567223

碩士 === 國立中央大學 === 資訊工程研究所 === 90 === Delivering real-time streaming over the Internet is one of the critical applications nowadays. Novel real-time Internet applications have bandwidth, delay, and loss requirements. However, the current Internet offers best effort services without sufficient Quality of Service assurance. To provide an efficient bandwidth allocation for multimedia applications, end-to-end control is necessary. Specifically, the issues of bandwidth adjustment and TCP-friendly should be properly addressed. This thesis presents a QoS adjustment architecture for real-time applications, which includes transport layer and application layer. In transport layer, the video sender adjusts the transmission rate by the feedback information (RTCP) from the receiver. In addition to the traditional loss rate for rate-adjustment decision, the thesis compounds loss rate and jitter as feedback information and adjust the transmission rate according loss-jitter adjustment parameters (LJA). From the LJA scheme, the continuous scales of bandwidth will be maintained for a RTP connection; however, the codec scales for the multimedia applications could be discrete. To support both of scales, a mechanism is applied to map the continuous bandwidth to the codec bit-rate. To address the unavoidable packet loss, an error recovery mechanism by retransmission is adopted to enhance the reception quality in application layer. The results show that the proposed architecture does improve the bandwidth utilization and reception quality for real-time applications.