@himey @HomerJAU
I did some testing with MKA and M4A atmos files neither are playing gapless in Kodi 19.3. They both have a half second gap. I tested between The Beatles Polythene Pam and She Came In Through the Bathroom Window, an obvious gapless situation.
For the MKA: I used MAKEMKV to generate the MKV from the disc, then MKVToolNix to split by chapter.
For the M4A: I used Music Media Helper to split the MKV by chapter to M4A.
As far as tagging you can tag MKA files in mp3 tag using the Musicbrainz source. And obviously M4A modules can be tagged in Picard directly.
I assume gapless for MKA should be working. Any settings to change to get it to work or properties of the file to look at?
thanks!