convert: Doesn't convert lossless AIFF on import

[Freso]

The convert plugin doesn't register an AIFF file with a pcm_s16be stream as lossless, and thus imports as-is when never_convert_lossy_files is set.

beet -vv import and beet config output: https://gist.github.com/Freso/01e5185503ec40b78e8b43bdcc98c241
Pre-tagged data of the imported files (via ffprobe): https://ptpb.pw/APyUNbU6z8_185dEUL7rYMMAyAow

[Freso]

Trying to run the convert command post-import also makes convert not convert them, due to the never_convert_lossy_files setting I guess.

[sampsyo]

Well, that would do it! There's a hard-coded list of lossless format names, and it doesn't include AIFF:

beets/beetsplug/convert.py

Line 42 in 0f4b454

LOSSLESS_FORMATS = ['ape', 'flac', 'alac', 'wav']

I'll add AIFF to the list. Thanks for pointing this out.

[Freso]

Hm. That's a bit of a shortsighted approach though, we should look into doing something more clever. ".aif" can contain lossy formats too, just like ".ogg" can contain FLAC audio. Should I open a new ticket for this?

[sampsyo]

Sure! The thing to do, I suppose, would be to add a lossy field to MediaFile that more accurately detects lossiness per-format.