Conformance for xvc is defined as follows:

A bitstream is a conforming xvc bitstream if and only if the current version of the reference xvc decoder successfully decodes the bitstream and returns “Conformance verified.”.

An encoder is a conforming xvc encoder if and only if it produces conforming xvc bitstreams.

A decoder is a conforming xvc decoder if and only if it produces identical output as the current version of the xvc reference decoder for all conforming xvc bitstreams.

Implementations of xvc encoders and xvc decoders may include methods that are not included in the xvc reference encoder and that are not included in the reference decoder. Although this is perfectly valid, the xvc licenses and the xvc indemnification clause are limited to the methods that are included in the current version of the xvc reference software.