一個有效的遺失率估算法之設計與實驗

Design and Experiment of an Effective Loss Rate Estimation Method

10.6382/JIM.200707.0229

陳俊麟(Chin-Ling Chen)；李建用(Jian-Yong Lee)

遺失率 ； 交通量測 ； RTP ； RTCP ； loss rate ； traffic estimation ； RTP ； RTCP

資訊管理學報

14卷3期（2007 / 07 / 01）

229 - 266

繁體中文

本文假設在傳送端有一個可支援兩個相同內容但不同語音音質檔案（PCM和GSM）的雙模式編碼器。傳送端根據以變動框架長度為基礎之遺失率估算法，來估算目前網路上封包遺失的狀況，並以此作為切換高低音質檔案的依據。此演算法可過濾短期突發交通，並呈現長期交通之趨勢。除具有穩定與敏捷的特性外，此演算法亦能避免音質切換過度頻繁。

In this paper, we assume that the sender supports a two-mode codec with two audio sample files (PCM and GSM). The sender tracks the packet loss status according to the algorithm-loss rate estimation based on variable frame size and switches two audio sample files in accordance with packet loss status. The proposed algorithm smoothes short term variations in loss rates, while responds quickly to real changes in the loss rate of the traffic. The ability of the algorithm is qualified by the agility, stability and avoidance of frequent switching for two sample files.

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