The POPM frame stuff (in_mp3 & ml_local) that Benski posted in your thread was included in 5.572
However, we didn't document it, because it's a work in progress.
We disabled it by default, and to enable it you need to manually set:
So... the newer ml_local.dll fixes two 5.57-specific bugs related to ratings:
1. Rating is lost when updating mp3 file info
ie. rate a file in winamp, then view File Info (Alt+3) for that file,
and the rating you just set is gone.
2. When writeratings=1 is set in gen_ml.ini, m4a files temporarily lose metadata & format info when you rate them.
ie. add an album of m4a files to the playlist,
rate the first track,
then try to play it - and notice how it skips to the next track.
If you view File Info for that 1st track, the metadata & format info are empty.
However, when you rate track 2, then track 1 becomes playable again,
and the metadata & format info return,
but then track 2 is affected by the bug instead.
The only way to fix it was to make a physical copy of the last track and rate that last.
Then all the album tracks were ok, and you could then close winamp and delete the copied file
(Windows wasn't letting you delete said file, because it was locked whilst Winamp was open).
The new ml_local fixes all that.
The first bug occurred regardless of the writeratings setting, but was caused by the implementation of that feature.
Oh, and it also fixes the tabbing order of Director & Producer in the Edit Selected Items (Ctrl+E) dialog.
Re: "what if the ML already has ratings? which takes precedence? what scale is being used to represent the ratings? 0-255?"
Well, if you've already rated an mp3 in Winamp before the popm feature was implemented/enabled,
then the rating will only be stored in the ML database.
If you rate it again in Winamp, then both the mldb entry and id3v2 popm field will be updated,
so Winamp will then read the new value.
If you rate it externally with a program/app that writes ratings to the popm frame (ID3FID_POPULARIMETER),
then as with all things when edited externally,
you will need to refresh the metadata in the library for Winamp to be able to see it.
ie. Media Library -> Local Media view -> song(s) -> right-click -> Read metadata on selected items
Yes, we're using the WMP-style 0-255 scale for ID3FID_POPULARIMETER
The ID3FN_RATING field stores the Rating within the POPM frame.
Though note that the IDFN_RATING is not standardized.
e.g. Some players/systems use a 1-10 scale, and then divided by 2,
some use just 1-5,
some use 0-255 (and the scale might not always coincide with wmp's version above)
etc etc etc.
At the moment, I think we read popm 0-255, but write 1-5,
which is why currently, eg. a 1-5 star rating in Winamp only shows as 1 star in Windows, heh
(I guess this will need changing).
By the way, I strongly recommend that you DO NOT use Windows Explorer / WMP in Windows 7 to edit any tags whatsoever, including star Ratings, because it destroys custom TXXX frames such as Album Artist and ReplayGain:
That's a pretty bad bug in Win7, and I'm quite amazed that it hasn't been patched yet.