IIRC, GPM stored user uploads in MP3. If you uploaded a non-MP3 file, it was transcoded into a MP3 during upload. It is this file that GPM takeout is providing.

IIRC, GPM stored user uploads in MP3. If you uploaded a non-MP3 file, it was transcoded into a MP3 during upload. It is this file that GPM takeout is providing. Separate from that, GPM matched your uploaded MP3 file against the service music corpus, and if there was a match, the service streamed the canonical version. Originally the streaming service used 320 kbps MP3, but later the service switched to 256 kbps AAC. GPM takeout does not provide the canonical version.