More Compliant Vorbis Comment Ratings (RATING=0-100 scale)

mojolo commented 3 years ago

Another Ratings issue/request....

Current QL Behavior

Currently, QL stores vorbis comment (FLAC, OGG, etc) ratings on a floating point scale of 0.0 - 1.0 in the rating:quodlibet@lists.sacredchao.net tag, eg:

rating:quodlibet@lists.sacredchao.net=0.8

The proposed change

While there is no officially defined standard for storing ratings in Vorbis Comments, there is a commonly used informal standard. This request is therefore two-fold:

Use an integer scale of 0-100 for Vorbis Comment ratings.
Store Vorbis Comment ratings in a simpler RATING tag (without an email), eg:

rating=80

Benefits of this change

This change will increase compatibility with other players and taggers because:

Many music players and taggers implement integer ratings and don't understand floating point ratings well.
Many music players and taggers read and write to the simpler RATING vorbis comment and are not configurable.

For example:

Kid3 uses a scale of 0-100 for Vorbis comments (0-255 for POPM). There's no support for floating point numbers.
Musicbee uses 0-255 for POPM and the informal standard for Vorbis Comment ratings: 0-100 scale and the RATING tag. See this thread.
Musicbrainz API uses a 0-100 ratings scale.
The Vorbis Comments entry on Wikipedia indicates that "Most applications also support common de facto standards, such as DISCNUMBER, RATING... Ratings are usually mapped as 1-5 stars with 20,40,60,80,100 as the actual string values."

Any issues this might cause

Possibly substantial refactoring of quodlibet's rating code.
Issues updating users' existing library/tags that use the current rating system.

bassstorm commented 3 years ago

Just to add, that I see even ratings like 0.6000000000000001 in my library.

declension commented 3 years ago

The real problem for all these kind of changes is the migration of all user's existing tag values

bassstorm commented 3 years ago

Perhaps, with help of operon should be no hassle to run a massive update once...

declension commented 3 years ago

Perhaps, with help of operon should be no hassle to run a massive update once...

The problem is that's a CLI and fairly separate; we have a basic but little-used migrations system, but this would require something a lot slower and scarier for every use (or optional I guess)

declension commented 3 years ago

One option I realised is QL could probably just write the simplified rating=80 as well.

And then read it (converting to QL internal floating point) if found but no other specific-email rating found - else ignore

bassstorm commented 3 years ago

And then read it (converting to QL internal floating point) if found but no other specific-email rating found - else ignore

I'm not quite sure I got the second part...

MountainX commented 2 years ago

I would like to add that this issue is the only thing preventing me from switching to QL. I love everything else about QL and I want to switch to it, but most of my music consists of flac files and they already have ratings of 0-100, as described above in this issue.

When I try to manage my music via QL, it creates a ratings disaster. All songs are displayed with the maximum (i.e., 10 of 10) stars rating. I am also unable to use QL ratings in a way that is compatible with any other application I use (whether Dolphin file manager, any other music player or any of the tag editors I use, or even just directly examining the tag contents with a library like Mutagen).

If I set QL to save ratings and play counts, it removes the existing ratings and does not add any rating or playcount in any tags that I can find, so I simply lose my existing ratings.

I am reading through the other issues to learn more. If I see that all my issues are not currently reported, I will add a new issue. I am learning Python and I hope to be able to contribute to QL in the future -- assuming I can actually begin using it, which depends on finding some resolution to this particular issue first.

declension commented 2 years ago

Another (riskier but universal) option perhaps (need to think more) is to consider any FLAC rating <1 as "old" when reading, and multiply by 100, and write all modified files with integer 0..100 scale. Eventually (or with a force write on all library) everyone's libraries are migrated.

MountainX commented 2 years ago

I'm starting to see the momentum shift toward the 0.0 to 1.0 scale. It now looks to me like the 0 to 100 scale in FLAC / Vorbis metadata is going to be the "old" way... Obviously, this is just one person's opinion.

Previously I have referenced this specific page (issue) multiple times in support of the 0 to 100 scale, but I'm abandoning support for it now and I'm on board with the 0..1 scale. Also, this issue [https://github.com/quodlibet/quodlibet/issues/3812#issuecomment-932235113], mentions an "advanced config setting" but since I decided to stick with the 0..1 scale, I did not try it.

sammypanda commented 4 months ago

I would say 0-100 scale is better, why use a decimal when it isn't needed especially given the quirks.

Or just the option to change the modifier for the ratings tag in the config.

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