ISO Base Media File Format And It's Extension In AVS Video Stream

With the rapid development of computer and network technique in recent years, multimedia application plays more and more important role in people's life. Audio and video application is the primary one, in which the media file storage format is a key part. As is well known, pure video stream only can be played orderly, and can't be random accessed or played in network. File format is designed to solve these problems.This thesis introduces the ISO base media file format in detail, which is defined in MPEG-4 Standard and derived from MOV file format. In physical structure, this format is object-oriented, every objects called 'atoms' have their specific layers; and in logic structure, file is composed with tracks, mainly media tracks and hint tracks, which are used to playback and stream in network. There can be several audio and video tracks in one file without any interference. Also there can be more than one hint tracks to serve one media track, which will not affect the local playback.Similarly the media data, stored as it is in a protocol-unaware fashion, can be streamed with any one of it's hint tracks. The protocol information is built in such a way that the streaming servers need to know only about the protocol and the way it should be sent; the protocol information abstracts knowledge of the media so that the servers are, to a large extent, media-type agnostic. They are two important characteristics in ISO file format. In the second chapter, all main atoms' structure and usage are set forth. Then, it's explained how to use informations in atoms via local playback and network streaming process.At present, many file formats are derived from ISO file format and defined in specs, such as MP4, AVC, MPEG-21, JPEG, 3gpp and etc. This thesis will explain how to encapsulate AVS video stream, to accelerate the...