ISO/IEC 23001-4:2017定义了能够描述可重构视频编码（RVC）框架中编解码器配置的方法和一般原则。它主要解决可重构视频方面的问题，并且只关注RVC框架内视频编解码器配置的表示
在RVC框架的范围内，规范性地指定了两种语言，即FNL和RVC-BSDL。FNL是一种描述FND的语言，也称为“FUs网络”。RVC-BSDL是ISO/IEC 23001-5中定义的BSDL的相关子集。该RVC-BSDL还包括进一步扩展的可能性，这些扩展对于提供视频比特流的完整描述是必要的。

ISO/IEC 23001-4:2017 defines the methods and general principles capable of describing codec configurations in the reconfigurable video coding (RVC) framework. It primarily addresses reconfigurable video aspects and will only focus on the description of representation for video codec configurations within the RVC framework.
Within the scope of the RVC framework, two languages, namely FNL and RVC-BSDL, are specified normatively. FNL is a language that describes the FND, also known as "network of FUs". RVC-BSDL is a pertinent subset of BSDL defined in ISO/IEC 23001？5. This RVC-BSDL also includes possibilities for further extensions, which are necessary to provide complete description of video bitstreams.