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[bunglemebaby]

After installing MC v14.0.46 (from v14.0.45) and running and Auto-Import many (thousands out of ~15K) of my files' ratings have been changed.  I loaded a library backup and did a "Update Tags From Library" and all appeared well. Then I did another Auto-Import and the ratings were again changed (I think for even more files this time, but I'm not certain of that). I have not touched these files with any other program.

I suspect that this:

3. Changed: Revised MP3 ID3v2 rating tag writing conversion formula to better match Windows.

has something to do with my problem, but I'm certainly not sure. I'm not really sure what better matching Window's rating tag effects, but I did use WMP once upon a time and rated plenty of music with it.

Any thoughts or things to look at?

Thanks,
JB

[Alex B]

The Rating tag uses the POP aka Popularimeter ID3v2 tag (only in MP3 files).

Here is the definition:

Popularimeter

The purpose of this frame is to specify how good an audio file is. Many interesting applications could be found to this frame such as a playlist that features better audiofiles more often than others or it could be used to profile a person's taste and find other 'good' files by comparing people's profiles. The frame is very simple. It contains the email address to the user, one rating byte and a four byte play counter, intended to be increased with one for every time the file is played. The email is a terminated string. The rating is 1-255 where 1 is worst and 255 is best. 0 is unknown. If no personal counter is wanted it may be omitted. When the counter reaches all one's, one byte is inserted in front of the counter thus making the counter eight bits bigger in the same away as the play counter ("PCNT"). There may be more than one "POPM" frame in each tag, but only one with the same email address.

<Header for 'Popularimeter', ID: "POPM">
Email to user   <text string> $00
Rating          $xx
Counter         $xx xx xx xx (xx ...)

(AFAIK, the counter part is not used in any program)


I checked three programs: MC13, MC14 (the latest build), and WMP11. All programs wrote different POPM values. The MC13 values are most logical because there is also the "unrated" zero value, but I guess MC must follow Microsoft because portable and other device manufacturers are more likely to support the MS standards. However, it is even more important to include read support for the old MC tags.

Here are the POPM values:

Code: [Select]

MC13

rating 1 = 51
rating 2 = 102
rating 3 = 153
rating 4 = 204
rating 5 = 255


MC14

rating 1 = 1
rating 2 = 65
rating 3 = 128
rating 4 = 192
rating 5 = 255


WMP11

rating 1 = Windows Media Player 9 Series  1
rating 2 = Windows Media Player 9 Series  64
rating 3 = Windows Media Player 9 Series  128
rating 4 = Windows Media Player 9 Series  196
rating 5 = Windows Media Player 9 Series  255
My suggestion for a fix:

- on a tag read

rating 1 = 1-51
rating 2 = 52-102
rating 3 = 103-153
rating 4 = 154-204
rating 5 = 205-255

- On a tag write use the exact WMP11 values, but also add the "Window Media Player 9 Series" string so that any external device or program that is designed to support the WMP ratings will probably understand the tag. This header string might also be useful in the future if a different scale is introduced. Then MC can be set to detect the used standard on a tag read.

EDIT

I attached two files:
- a screenshot of the POPM values in an old version of Mp3tag (the current version interprets the WMP ratings automatically and shows only the 0-5 "star" scale).
- a package of five small MP3 sample files with WMP11 ratings.

You must be logged in to the forum before the attachments are available.

[Alex B]

After installing MC v14.0.46 (from v14.0.45) and running and Auto-Import many (thousands out of ~15K) of my files' ratings have been changed.  I loaded a library backup and did a "Update Tags From Library" and all appeared well. Then I did another Auto-Import and the ratings were again changed (I think for even more files this time, but I'm not certain of that). I have not touched these files with any other program.

If you did the library restore and tag update with an earlier build of MC14 (or MC13) you just reverted the changes in the older program version and in the file tags. The new build interprets the POPM file tags differently when the files are imported or the library is updated from the tags.

You can restore an older MC13/14 library backup file using the new MC14 build and it should show the correct ratings. You can save the tags with the new build, but it will use the new scale.

[bunglemebaby]

You can restore an older MC13/14 library backup file using the new MC14 build and it should show the correct ratings. You can save the tags with the new build, but it will use the new scale.

Indeed, that did work well. I actually did use the latest version of 14 to do the 'update tags from library' before. I'll assume user error and move on with life.

Thanks for the info and pointer. They are much appreciated.

Regards,
JB

[Matt]

Thanks to Alex for all the good information.

And sorry for the confusion.  The beauty of standards are that there are so many to choose from!