说明：  ISO/IEC 14496-1,MPEG4的系统层文档,各种描述子详细介绍了Video和Audio ES的组成结构,解码时音视频数据的获取就是建立在此部分理论基础之上的,学习MPEG4编解码必备手册.
(ISO/IEC 14496-1, MPEG4 system level documentation, various detailed description of the Video and Audio ES composition, audio and video decoding data access is established in this part of the theoretical basis, learning MPEG4 codec required manual.)