The VG Resource

After extracting the files from Transformers: The Game (Wii), many of the audio files are in the standard .dsp format. The music files, however, are in a .gcm format, which is the format that most GameCube roms are stored in (if not .iso). How could I convert them to a more standard format? Has anyone else seen this before?

I am new to ripping Wii files btw.

Any help would be appreciated, thanks!