I have an MKV file with both EAC3 and TrueHD audio tracks. The former is set as the default track, according to MKVToolNix (see screenshot).
However, the Apple TV wants to play back the file with the TrueHD audio selected, thus causing a transcode (a photo is attached for this also). The EAC3 track allows for Direct Play, which is preferred. I can manually change tracks of course, but why is the Apple TV not honouring the default audio track flag in the MKV?
My guess it it plays whichever track comes first (lower ID number). Try swapping the track order. You can do this with ffmpeg -map option, or maybe with mkvtoolnix too.
We do not use the default track flag. We look for the first track that matches your language preference. Sometimes the default flag may be on your non-preferred language, or the entirely wrong track.
OK, thanks for clarifying. Glad to know that my Plex install is working as designed (even if I’m not crazy about the choice to ignore default flags!).
My reasoning for wanting Plex to use the default flags is that one can change the default flag on an MKV without having to re-multiplex the file, so if you have a file like the one I mentioned earlier in the thread, you can quickly reassign the default flag at the file level. Just my two cents!
This is not true if the first track is mono. Plex will always pick a stereo track over a mono track even if the mono track is first/default/forced. This is a big issue with older films where the film audio is mono and the commentary is in stereo. The commentary will play instead of the film audio.
