IssueTracker

The Android Media Store tries to detect the encoding in tags in music (even if the file format specifies a certain encoding) and misdetects the encoding often, which causes characters to be shown incorrectly, especially in non-english languages and it does so in non-intuitive ways (as the detection apparently depends not only on the characters themselves, but also on the characters around them).

This is easily reproducible if you create two files (for example FLAC, but other formats should work as well) with the title tags set to "Der aaaaaaaaüsterer" and "Der aaaaaaaaüsteraa". Even though the files only differ in those two bytes (see screenshot 1), one of the files is shown correctly (detected as UTF-8), one is shown incorrectly (detected as Latin-1) (see screenshot 2).

This issue is known since 2014, but has been closed as it was stale:
https://issuetracker.google.com/issues/37013213

But this is still an issue and it affects all media players I've tested, as they all use the Media Store API.