ISO/IEC 23001-4:2014 defines the methods and general principles capable of describing codec configurations in the so-called reconfigurable video coding (RVC) framework. It primarily addresses reconfigurable video aspects and focuses 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.