Research Of MPEG-4 File Stripping Strategy And Flow Control Mechanism

With the development of Internet, cluster and multimedia technology, multimedia information becomes representation of next Internet information. Multimedia information compress technology is one of the key technologies in multimedia communication area. So the international coding standard MPEG-4 becomes focus of the research. The advantage of MPEG-4 coding standard is that the multimedia files using MPEG-4 coding need less storage space and network transporting bandwidth than other MPEG coding standards. These characters can benefit the performance of Video on Demand Server on cluster.According to the logical character of multimedia files, This article uses a UDFS(Uniform Description File Striping Method) strategy to strip MPEG-4 files. This method strips file after analyze the inside logic of this file. It is much fitter for the character of multimedia files than the method of stripping according to files' physical position. Stream files' information which UDFS method created can help VoD server dispose transporting different format files transparently. It enhance the expand ability of VoD server. This article also bring forward a file redundancy algorithm named RAS(Strip File Redundancy Algorithm based on Statistic), and use Chained Decluster distribution algorithm to distribute strip files. Using this file redundancy and distribution algorithm can benefit VoD server's load balance and fault tolerance abilities. The experiment result shows that the file redundancy and distribution algorithm can enhance the performance of our VoD server very well.This article creates stream information layer in stripping file process after analyzing the character of MPEG-4 standard file. This layer helps server control stream flows. The article brings forward file level flow control mechanism, this mechanism use stream information layers to choose strip files with less data rate to send when networks is congested. The result of experiment shows that this mechanism can decrease sending rate when network is congested, and can enhance our VoD server's performance.