I was having a go at it myself - if you check the "Dumping GD-ROM discs..." topic in this subforum, you'll see the crude method that I used (summary: convert a raw ripped game data ISO to BIN, then literally join the ripped audio tracks in a seperate BIN file from the game onto the beginning of the data file, since the CDDA comes before the game data) which completely failed.
Inserting the CDDA tracks into a self-boot CDI would be more pratical, but I don't know of any program that can do this. Since inserting the audio tracks would probably require them being converted them to WAV (if you have them ripped in a single RAW or BIN format file, which are technically the same thing anyway
) and then being seperated into their respective tracks.
It's highly unlikely that any program out there could do this; only way I could see any program being able to do it automatically (and accurately!) is if it analysed the table of contents (TOC) file from whatever DC game the audio is from, matched the LBA values & running time lengths / gaps between each track to the RAW/BIN (or WAV) file, and then cut each of the tracks to their respective seperate files.
Once you've got around that, it'd then be a lot more viable to make something to inject the individual tracks before the beginning of the data track (and obviously adjust any relevant disc layout details in the CDI so that everything can be correctly read - this is where my crude BIN/CUE method falls apart, because joining two files together with the "copy /b" command typically doesn't adjust the disc layout details for you, and so it doesn't work at all when mounted - like having to write the damned CUE sheet in the first place isn't hard enough
).
