First few word: Codec identification is actually most important part of the container, because all other so technically great features are "under the hood". Fourcc is among the few things that users (even windows one!) are aware these days . Second: The real issue is not how we will save and name codecs. The real issue is how to prevent propagation of existing fourcc schemes into nut, with all their drawbacks. What I think we may need: format_id - mandatory field. identification of the format, by standard or bitstream syntax. e.g. "mpeg2","h264","theora", "vorbis". profile - optional field. depends on the specifications (e.g. main simple, etc...). This field informs that full possibilities of the format are not used. encoder - optional. Identifier of the encoder used to create the stream. Could be used to workaround bugs. Or blame for poor quality. fourcc - optional. Backward compatible code if the format have such. Same as the file transcoded or one from the "clean list". Used only by decoders that don't have format_id table. --- At first decoders will use only fourcc, because that's what they know. When nut is widely accepted there will be more decoders that use format_id, and not fourcc. When other format dies, so will do fourcc. You may wonder what's the difference between format_id and fourcc. Think of format_id as trademark. Lusers may load fourcc with all the crap from avi and qt, but format_id is reserved only for official standards and bitstreams. Of course anybody could try to make up new format_id for existing standards. However giving that there are other means for having clean separations (profile,encoder), it could not happen by accident. The profile field is needed to prevent spamming and spawning of new format_id's for newer versions of the stream (e.g. theroa3.4.12). It could also be used by hardware players/stream servers to pick up streams they can play. The encoder field is the field that is supposed to take all the spam from the clone codec makers. It should describe exactly the encoder and to even allow workarounding the know encoder bugs.(e.g. xvid id and bitstream version that is increased every time encoder bug is found and fixed) P.S. Even if you don't accept format_id and leave only the fourcc, I would be happy if you think a little about profile and encoder_id.