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Author Topic: PUBLISHER tag behavior for FLAC files  (Read 4350 times)

Frobozz

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PUBLISHER tag behavior for FLAC files
« on: May 05, 2009, 03:00:20 am »

I have noticed some strange behavior with the PUBLISHER tag in FLAC files.  If I edit the Publisher tag using Mp3tag and edit the same Publisher tag using Media Center I end up with two copies of the PUBLISHER tag in the FLAC file.  I'm not sure if it is Mp3tag or Media Center that is not always recognizing the Publisher tag written from the other application.  Or is it expected behavior for that particular tag?

I'm using MC 13.0.152

Here's a screenshot of the Mp3tag dialog showing all tags in the file.  Note that there are two Publisher tags.  One written from Mp3tag and one written from Media Center.

http://pix01.com/2b@0Lrf
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Alex B

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Re: buggy? PUBLISHER tag behavior for FLAC files
« Reply #1 on: May 05, 2009, 05:35:13 am »

MC13 creates a tag frame that is named "Publisher" also inside the FLAC file.

Mp3tag writes the field contents to an "Organization" tag frame. It converts the displayed name to "Publisher". Unfortunately it does not provide any visual indication when such conversion happens.

The reason for the behavior may be historical. In MP3/ID3v2 tags similar info is saved to the standardized TPUB (aka Publisher) frame. For some reason the Ogg Vorbis developers decided to define a frame named Organization for the same info (FLAC uses same the physical tag format): http://www.xiph.org/vorbis/doc/v-comment.html.

Obviously the Mp3tag developer wanted to provide a system that can tag Publisher info to both formats using the same visible tag name.

A workaround in MC would be to create an "Organization" user field. If you want you can change its displayed name to Publisher, but in that case you may need to change the displayed name of the original Publisher field to something else in order to avoid confusion inside MC.
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Frobozz

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Re: PUBLISHER tag behavior for FLAC files
« Reply #2 on: May 05, 2009, 08:12:19 pm »

I need to read up on the various tagging standards and best practices.  I only have a limited understanding of the details.  The Vorbis doc was informative.  I'll have to read up on ID3 info.

The Vorbis doc says it is permissible to have multiple entries of the same field name:
Quote
Field names are not required to be unique (occur once) within a comment header. As an example, assume a track was recorded by three well know artists; the following is permissible, and encouraged:

              ARTIST=Dizzy Gillespie
              ARTIST=Sonny Rollins
              ARTIST=Sonny Stitt
So the files I have with two PUBLISHER tags aren't wrong.  It causes unexpected behavior when it is assumed to be a single entry field, but is not wrong.

In my little experimentation is seems that MC is reluctant to read in the PUBLISHER tag even if the PUBLISHER field in the database is empty.  Even after doing a "update library from tags".  I find that odd, but there is likely a reason for that behavior.

I manually entered label and catalog numbers for some albums in the PUBLISHER tag using Mp3tag.  I also entered the same info in the COMMENT tag so even if the PUBLISHER tag gets whacked or MC doesn't want to read it, the info is still there in the COMMENT tag and should be safe.
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Alex B

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Re: PUBLISHER tag behavior for FLAC files
« Reply #3 on: May 06, 2009, 02:53:45 am »

Quote
...So the files I have with two PUBLISHER tags aren't wrong. It causes unexpected behavior when it is assumed to be a single entry field, but is not wrong.

In my little experimentation is seems that MC is reluctant to read in the PUBLISHER tag even if the PUBLISHER field in the database is empty.  Even after doing a "update library from tags".  I find that odd, but there is likely a reason for that behavior. ...

In your case the files don't have two Publisher tags. The files have an Organization tag and a Publisher tag.

MC reads and writes "Publisher" and displays it is "Publisher". As I said, the displayed name can be changed but that affects only the display.

MP3tag reads and writes "Organization" and displays it as "Publisher". (When only Mp3tag is used for tagging a Publisher value.)

MC can read, write and display "Organization" if you create a user tag with the name Organization. The displayed name can be changed.


In general, I don't think MC is designed to handle separate tags that have the same names, but your issue is different.
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Frobozz

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Re: PUBLISHER tag behavior for FLAC files
« Reply #4 on: May 06, 2009, 05:08:18 am »

Can you recommend a utility that will show the true ID3 tags in an MP3 and the true Vorbis tags in a FLAC?  It would seem that all of my tagging tools are giving me an altered view.
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Alex B

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Re: PUBLISHER tag behavior for FLAC files
« Reply #5 on: May 06, 2009, 06:13:31 am »

MC has a pretty good "tag dump". It comes directly from the file. Select a file and click the first line in Action Window > Tag to open the Detailed Format Information window. It doesn't always show everything (not all possible tags & formats are compatible with it), but, for instance, this Publisher/Organization behavior can be seen.

Here's an example of the displayed info (you can do "right-click > copy to clipboard" in the format window):

Quote
Free Lossless Audio Codec (FLAC)
  44.1 kHz Sample Rate
  16 Bits Per Sample
  2 Channels

  Min Block Size = 4096
  Max Block Size = 4096
  Min Frame Size = 5792
  Max Frame Size = 11797
  Padding Block = 7868 bytes

Vorbis Comment Block (364 bytes):
  Vendor String = reference libFLAC 1.2.1 20070917
  BPM = 66
  INTENSITY = 4
  JR_DATE = 39448
  PEAK LEVEL = 0.6700699925422668
  Organization = tagged by mp3tag
  REPLAY GAIN = -7.447390079498291
  replaygain_track_gain = -1.46 dB
  replaygain_track_peak = 0.670074
  Title = Lamb
  TOOL NAME = Media Center
  TOOL VERSION = 13.0.163
  Date = 2008
  PUBLISHER = tagged by mc

A hex editor can show everything. Depending on the format the tags may be in the beginning of the file or in the end of the file (or in both places, like when the files have ID3v1 and ID3v2 tags). Here' s a free hex editor that can open big files easily: http://mh-nexus.de/en/hxd/ .
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Frobozz

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Re: PUBLISHER tag behavior for FLAC files
« Reply #6 on: May 06, 2009, 08:08:09 am »

MC has a pretty good "tag dump". It comes directly from the file. Select a file and click the first line in Action Window > Tag to open the Detailed Format Information window.

Oh cool.  I didn't even know MC did that kind of a tag view.
Now I see what is going on.  Thanks!
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