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Author Topic: Where Does Media Center Store ID Tag Data?  (Read 2168 times)

sarcanon

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Where Does Media Center Store ID Tag Data?
« on: February 20, 2021, 05:29:02 pm »

I'm a relatively new used of Media Center, so there's still a lot for me to learn about the theory of operation with large collections of music (almost exclusively classical and opera), because this is obviously a program with a very deep and mature feature set.

My question for the moment is, where are the ID Tag data stored? I initially thought that they were stored in the media files themselves. I deduced this from the fact that as I edited tags inside Media Center, I would see the file modified timestamps on the media files change simultaneously. However, I've just started to import a new set of music files into my library which consists of "monolithic" FLAC files, i.e., each media files contains an album with multiple tracks. These files are all accompanied by CUE files with some basic track details in them. Previously I've only ever had single-track FLAC files in my library.

However, when I modify ID tags for the music in these multi-track FLAC files, I observe that the file modified timestamp does not change, yet the modified tag data appear to persist even after quitting and re-launching Media Center. Which leads me to the conclusion that the ID Tag data is being persisted somewhere else, perhaps in an internal database of some kind?

1. Where can I find out more about where Media Center stores ID tag data, and how it is synchronized with the tag data in the media files themselves?

2. If Media Center is storing ID tag data in an internal database, how do I sync these tags with the multi-track media files? I am worried that if I ever had to rebuild my Media Center library, I would lose all my changes to any metadata that wasn't stored in the media files (or the CUE files) independently of Media Center.

I hope this all makes sense, and I apologize if this has all been asked and answered before. I did some cursory searching of the archives before posting, but I was not able to find anything relevant to my queries.

Many thanks in advance.


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JimH

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Re: Where Does Media Center Store ID Tag Data?
« Reply #1 on: February 20, 2021, 06:02:56 pm »

They can be stored in the file or not, depending on how you've set MC.

The options page has a search window at the bottom.

The wiki has a lot of information about tags.
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wer

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Re: Where Does Media Center Store ID Tag Data?
« Reply #2 on: February 20, 2021, 07:03:36 pm »

Welcome to the forums, sarcanon.

Your question is well though out, which is both rare and appreciated. :)

If you google "jriver tagging" you'll find quite a bit of info, including that wiki article...

But in short, it works like this:

MC is a database; all tagging information is always stored inside MC's proprietary database.
In addition, MC can write tag information to media files. In order for this to happen, a couple of things must be true:

1. MC must be configured to be allowed to write tags (this is the "Update tags when file info changes" option).
2. For each and every field, there is an option to write that field to file tags or not. If that is not enabled, the info will only reside in the database.

Finally, if MC is configured to write tags to the media files, the media file itself must support tagging.  WAV files have very limited tagging support. ISO files have none at all.

For those sorts of files to be tagged with any arbitrary info you want, you can configure MC to use "sidecar" files for those file types. In that case, MC will write an XML file next to each media file, to contain its tag info that the file itself can't hold.

MC has two reciprocal commands (accessible via right-click menu): "Update library from tags" and "Update tags from library".  When these are invoked against the selected files, MC will either read the tag information from the file and replace the library data with what it finds, or write the library data to the file, overwriting what is in the file currently.

I always suggest that people configure MC too always write all the tag information they care about to the media files (using sidecars as necessary, as it is for video files for example).  That way, if the file is shared, or moved to a different PC, the metadata goes with it.  Likewise, if something happens to your library, you can retrieve the metadata from the tags.

Be warned, there are some fields I would not write to file tags. "Last Played" is one example. If you write this to the file, the file will be modified every time you play it, which means it will always be dirty for backup. In my view, that is worse than losing the "Last Played" data if you lost the library.

Regarding synchronization, if the appropriate options are turned on, MC will constantly update file tags as you make changes in the database.  If you want to try to do sneaky things and update tags in the files and are hoping MC will automatically synchronize those changes too, be careful, but you can turn on "Run Auto Import in background" and enable the "Update for external changes" option. That way, MC will periodically note that the files have been modified, re-read the tags, and update the library as needed (although it will not delete data from the library just because you have cleared a tag in a file).

I hope this helps.
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sarcanon

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Re: Where Does Media Center Store ID Tag Data?
« Reply #3 on: February 21, 2021, 10:54:54 am »

If you google "jriver tagging" you'll find quite a bit of info, including that wiki article...

Finally, if MC is configured to write tags to the media files, the media file itself must support tagging.  WAV files have very limited tagging support. ISO files have none at all.

For those sorts of files to be tagged with any arbitrary info you want, you can configure MC to use "sidecar" files for those file types. In that case, MC will write an XML file next to each media file, to contain its tag info that the file itself can't hold.

MC has two reciprocal commands (accessible via right-click menu): "Update library from tags" and "Update tags from library".  When these are invoked against the selected files, MC will either read the tag information from the file and replace the library data with what it finds, or write the library data to the file, overwriting what is in the file currently.

I hope this helps.

Thank you for that very thorough and enlightening reply. A follow-up question, if I may.

Regarding support for tags, I found a page in the Wiki titled "File Types and Tags", but it was empty. So I could not find what support that multi-track FLACs provide. I know from experience that single-track FLACs do support tags, but the multi-track FLACs are my concern at the moment.

I modified my options thusly:

Update tags when file info changes: Checked
Sidecar tagging Mode: Save in both sidecar and internal tags (if supported)
Write to external sidecar files for media types: Audio;Data;Video

I then modified some tags in JRiver in a multi-track FLAC file. Highlighting all 12 tracks from the album contained in the multi-track FLAC, I then selected Update Tags (from Library) from the contextual menu. JRiver then presented a dialog saying "12 files updated (12 failures)" and then listed the full paths on disk for each of the 12 tracks it attempted to modify (but failed). However no details were provided as to why the operation failed. Just to confirm, I looked in the directory in Windows File Explorer and saw that no files were modified or added in the directory containing the FLAC that I had intended to modify.

The media file is on a hard disk volume that is not write-protected, so there's no reason why it should not have been able to write the changes out to disk. Is there a debug log file somewhere that I can consult to determine why the updates failed?

Many thanks in advance.


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wer

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Re: Where Does Media Center Store ID Tag Data?
« Reply #4 on: February 21, 2021, 01:00:56 pm »

I think your only hope of tagging multi-track flac files is to use cuesheets. But you will have no end of trouble.

I would strongly suggest you just split them into multiple flacs.  MC supports gapless playback so it will not hinder your playing of the tracks, but will make your management of them infinitely easier.

Learning about logging here: https://wiki.jriver.com/index.php/Logging
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sarcanon

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Re: Where Does Media Center Store ID Tag Data?
« Reply #5 on: February 21, 2021, 01:38:43 pm »

I think your only hope of tagging multi-track flac files is to use cuesheets. But you will have no end of trouble.

I would strongly suggest you just split them into multiple flacs.  MC supports gapless playback so it will not hinder your playing of the tracks, but will make your management of them infinitely easier.

Learning about logging here: https://wiki.jriver.com/index.php/Logging

Thank you for your reply.

Any suggestions for an application for splitting FLAC files? This would be for Windows, and preferably an application with solid support for batch handling large sets (3,000+), or a command line tool that I can script. I've tried an Medieval Software and found it wanting.
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wer

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Re: Where Does Media Center Store ID Tag Data?
« Reply #6 on: February 21, 2021, 01:56:11 pm »

I don't have the problem myself, but I think most people use cuetools. It's lossless and gapless.
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Awesome Donkey

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Re: Where Does Media Center Store ID Tag Data?
« Reply #7 on: February 21, 2021, 04:15:06 pm »

CueTools is great for splitting. Avoid Medieval, as it introduces sector boundary errors (SBEs) when splitting tracks. CueTools does not.
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