But there are many MPEG-7 self-defined description schemes in the standard of MPEG-7, these description schemes are defined with special language, which usually named DDL.

• 但MPEG-7的描述中使用了多媒体描述模式(MDS)和描述定义语言(DDL)，这对于一般的开发人员来讲过于复杂和缺乏可操作性。