Memory Copy Optimization for Streaming Gateway Transcoding: Models and Algorithms

Repeated memory copy during protocol translation inhibits capacity of a streaming media gateway. Unlike existing optimization techniques that rely on platform-specific features, this paper investigates algorithm-level platform-independent strategies. A mathematical concept of the buf-string is proposed to model the protocol transcoding process. Based on this model three payload extraction algorithms that can reduce memory copy are presented. The streaming gateway used in the Next-generation broadcasting (NGB) and the Next-generation on-demand (NGOD) system is taken as an example to demonstrate and evaluate our strategies. Experimental results from an x86 host and an embedded system prove that our strategies can reduce CPU overhead by 15% to 45%, and optimize the linear space complexity to a constant one.