Trackstat and Musicbrainz

[yocky]

As I understand it, tagging files with Musicbrainz will enable my ratings to survive when I rename or move the files (or both) because the files are uniquely identified by the Musicbrainz IDs rather than location and filename.

First of all, is my understanding correct? And if so then would the ratings survive being moved/renamed in any circumstance or would I require a full rescan followed by a restoration of the ratings from a backup file? I ask because my few tests of this have resulted in my rating being lost...but I haven't tried the complete rescan yet.

[erland]

As I understand it, tagging files with Musicbrainz will enable my ratings to survive when I rename or move the files (or both) because the files are uniquely identified by the Musicbrainz IDs rather than location and filename.

First of all, is my understanding correct?

Yes, but if you have a lot of compilation albums you might get an issue.
The issue is that some time ago Musicbrainz changed principes so they don't identify a track uniquely, instead identify a recording. If you have a normal album and compilation album with with the same song, this results in that they typically get the same musicbrainz id and in such setup TrackStat musicbrainz logic doesn't work reliably for these tracks. THere is an option in TrackStat settings page where you can disable musicbrainz logic if you are affected by this problem.

And if so then would the ratings survive being moved/renamed in any circumstance or would I require a full rescan followed by a restoration of the ratings from a backup file? I ask because my few tests of this have resulted in my rating being lost...but I haven't tried the complete rescan yet.

To things have to happen for it to work:
1. You have to do either an incremental scan or a full rescan after you have added musicbrainz tags to the files, else the tags aren't available in the LMS database.
2. TrackStat needs to perform its refresh operation once after the full rescan, this should happen after a rescan or at server startup unless you have explicitly disabled refresh in TrackStat settings page.

After this you should be able to:
1. Rename/move a file
2. Perform a rescan (incremental or full) to detect its new location/name
3. Let TrackStat perform its refresh operation after the rescan (or at server startup) which will result in that your ratings are restored.

If it doesn't work, I would suggest two things:
1. Install the free Database Query plugin and run the "TrackStat inconsistency/problems" and "Squeezebox Server inconsistency/problems" queries and see if they indicate and problems. You can also try the other Squeezebox Server and TrackStat queries to verify that you really have musicbrainz id's in the database.
2. Verify in the LMS/SBS server.log file that you get a message like "TrackStat: Synchronizing TrackStat data, please wait..." in the server.log file after a rescan is performed, if no such message exists it's an indication that the refresh operation has been disabled.

As a side note, if you have explicitly disabled automatic refresh, there is a button to do a manual refresh in the backup section of TrackStat settings page.

[yocky]

Thanks for all that. I'll do some more testing tonight.

As an aside, I'm attempting to tag these files with Musicbrainz IDs via MP3Tag. If I use that program and use Musicbrainz as the info source, is that tagging the files sufficiently? In which field is this new info going? Is it possible to identify a file that's had Musicbrainz IDs applied after the event, and if so how?

[erland]

As an aside, I'm attempting to tag these files with Musicbrainz IDs via MP3Tag. If I use that program and use Musicbrainz as the info source, is that tagging the files sufficiently? In which field is this new info going? Is it possible to identify a file that's had Musicbrainz IDs applied after the event, and if so how?

I don't know the details about how musicbrainz tags are stored in the files, it's Logitech code that scans them into the database and I just use what's there.
Mp3Tag usually does the right thing so I suspect that's the case also for musicbrainz tags.
There is a specification from musicbrainz.org for it which you can find here:
http://wiki.musicbrainz.org/MusicBrainz_Tag

I don't think there is any way to detect if a file has an old or new musicbrainz identity. The effect of the changed principle Musicbrainz did was just that some tracks changed musicbrainz identities. Most tracks have the same musicbrainz identtiies as before, i think it's mainly tracks on compliation albums that might have got a changed identity. The only way to be sure is probably to retag the whole library, but that could be a lot of work so I'm not sure it's worth the trouble unless you get some problems related to it. The old principle was preferred from a TrackStat perspective as it results in unique track identities.

[yocky]

Right, I'm getting nowhere fast with this.

I took 2 albums and ran some tests.

I rated a few tracks on Album1 then rescanned. I tagged Album1 and Album2 with Musicbrainz tags via MP3Tag and then rescanned. I rated some tracks on Album2 and rescanned. Then I moved Album1 and Album2 to a different folder and rescanned. I checked the server log and Trackstat was performing a refresh after each scan....but my ratings were gone from each album.

What am I doing wrong?

Having missed your Database Query advice to start with, I tried that. The Trackstat Inconsistencies showed a few problems but none relating to the albums I'm referring to. The Server Inconsistencies showed just one problem, an album with no songs (not related to the 2 albums I'm talking about, but how do I find an album by its ID number?). The Trackstat statistics query just gave me a list of basic statistics relating to number of times songs/albums and artists had been played/rated, no mention of Musicbrianz. The Squeezebox Server stats query just runs for ever with no results and makes the server completely unresponsive. How long should that run for on a library with 25k tracks?

[erland]

Right, I'm getting nowhere fast with this.

Can you mail me a small track which you have tagged with Mp3Tag so I can take a look at how the tags look like ?

[yocky]

Can you mail me a small track which you have tagged with Mp3Tag so I can take a look at how the tags look like ?

Sure, I've sent you the smallest one I was testing with this morning (to your Hotmail address).

I'd be interested to know what you're going to look for.

[erland]

Sure, I've sent you the smallest one I was testing with this morning (to your Hotmail address).

Did you send the right one ?
I can't find any musicbrainz tags at all in the one you sent.
What does the "View tags" item in the LMS web interface in when viewing details of the song say in your setup ?
If you don't see any tags there named something like MUSICBRAINZ_* it means that you do something wrong when changing the tags because they aren't written properly to the file.

I'd be interested to know what you're going to look for.

I was just going to look at how the tags look like, but as said above it seems like there isn't any musicbrainz tags at all in the file which also would explain why TrackStat isn't able to keep statistics when you move/rename the file.

[yocky]

Thanks for looking.

Right well that explains a lot, and yes I sent the right one. In fact I suspected that that that might be the problem. That's why I was asking in a previous post how I could tell if Musicbrainz tags had been applied. I didn't know about the "View Tags" option or I could have checked that myself.

I just tagged another (already rated) album with Musicbrainz own tagger Picard and sure enough I can see the Musicbrainz tags and the ratings survived a move. So given that I'd much rather use MP3Tag, what am I doing wrong? (Not that you're obliged to offer me support for a random piece of software you have nothing to do with.)

[erland]

So given that I'd much rather use MP3Tag, what am I doing wrong? (Not that you're obliged to offer me support for a random piece of software you have nothing to do with.)

Unfortunately I've only used Mp3Tag for some basic things, where it has worked excellent, so I'm afraid I can't say what' wrong.

It's probably better to ask in the ripping/tagging section of the forum, but some things to try:
- Can you modify other tags ?
- If not, verify that you can write to the music files, maybe they are write protected ?
- Also, remember to save in Mp3Tag, if I remember correctly the tags aren't actually written to the file before you select to write/save the changes.
- There is a preference setting in Mp3Tag where you can select which tag types it should write, it's important that you have told it to write v2 tags and not just v1 tags as the v1 version of the standard doesn't support custom tags such as musicbrainz tags. However, it looked like your file had v2 tags, just not musicbrainz tags, so I suspect this isn't the issue.

But ask in the ripping/tagging section of the forum if the above doesn't help and someone that really knows Mp3Tag can help you find the cause.