As someone else said, this almost always comes down to the device they’re using. Especially if it’s a Playstation console or a Smart TV (in my experience) as they don’t support x265 codec or have .ass support, or both

I shoved that whole nuke up my pussy

Are you after wireless or wired earbuds? And what kind of music do you generally listen to?

every phone had a different format, i remember the Razr had a deprecated tool to convert .mp3 to a format it could read and limited it to like…30sec audio snippets?