Hi, Paul Jessop here. I appear a long way up the thread and have been away enjoying the peace and quiet. I run the International ISRC Agency (as well as the US Agency). I hope this means I know how these systems work, what they can do and what they cannot do.
I was asked to comment on ISRC not appearing in MP3s as ID3 tags even though there is now a mechanism to carry an ISRC in a BWAV file (thanks to the great work by Barry Grint at MPG). I think these address two different objectives.
The master BWAV file carries the assigned ISRC to make sure that it is not used in the wrong project by mistake and that the correct ISRC is delivered with the recording when it is sent to online services etc.
The consumer MP3 (and AAC etc) has already gone through these quality assurance processes and while it might be useful for a media player to have access to the track's ISRC to look up more information in services like Discogs, it's not a showstopper if it doesn't. The important thing is that the ISRC was delivered (in an out of band electronic message) to the online service and will be reported back to the owner (direct or via a distributor) so that the owner knows what tracks sold (or were streamed) and in what quantity so it can fulfil its own obligations to pay artists etc. That does not depend on the ISRC being in the coded music file the consumer received.
There is one "use case" I am aware of. When micro-webcasters purchase track for streaming from an online service they need to be able to find the ISRC if they are to report it to the licensor. For that reason in particular I am trying to get the online services to include the ISRC in downloads. I'm not sure that they are particularly motivated though.
Much water has passed under the bridge since I was last here. We have been working very hard to create a registry for ISRCs. This won't distribute royalties or enforce payment from bad actors, but it will mean that when you get a royalty statement quoting a particular track with its ISRC, you can be sure that both you and the reporting entity are referring to the same track.
As always I'm happy to assist with queries either here or via the firstname.lastname@example.org