Hi,

I'm using gstreamer on Debian GNU/Linux unstable.
I noticed gstreamer (matroskademux) can't read the ARTIST tag in a Matroska file.

I made a Matroska file with some tags using mkvmerge.
mkvinfo shown all the tags I added to the file.
But gst-launch could not find the ARTIST tag while other tags could be found properly.

How to reproduce the problem:

1) Here is a xml file to describe the tags.

  % cat tags.xml 
  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE Tags SYSTEM "matroskatags.dtd">
  <Tags>
    <Tag>
      <Simple>
        <Name>ARTIST</Name>
        <String>ARTIST string</String>
      </Simple>
      <Simple>
        <Name>GENRE</Name>
        <String>GENRE string</String>
      </Simple>
      <Simple>
        <Name>TITLE</Name>
        <String>TITLE string</String>
      </Simple>
      <Simple>
        <Name>ALBUM</Name>
        <String>ALBUM string</String>
      </Simple>
    </Tag>
  </Tags>

2) Then I made a file "test.mkv" with tags.xml as following:

  % mkvmerge -o test.mkv --tags 0:tags.xml /usr/share/sounds/startup3.wav
  mkvmerge v4.6.0 ('Still Crazy After All These Years') built on Mar 11 2011 08:54:33
  '/usr/share/sounds/startup3.wav': Using the WAV demultiplexer.
  '/usr/share/sounds/startup3.wav' track 0: Using the PCM output module.
  The file 'test.mkv' has been opened for writing.
  Progress: 100%
  The cue entries (the index) are being written...
  Muxing took 0 seconds.

3) The tags ARTIST, GENRE, TITLE and ALBUM are correctly added to the file test.mkv.

  % mkvinfo -t test.mkv
  + EBML head
  |+ EBML version: 1
  |+ EBML read version: 1
  |+ EBML maximum ID length: 4
  |+ EBML maximum size length: 8
  |+ Doc type: matroska
  |+ Doc type version: 2
  |+ Doc type read version: 2
  ...snip...
  |+ Tags
  | + Tag
  |  + Simple
  |   + Name: ARTIST
  |   + String: ARTIST string
  |   + TagLanguage: und
  |   + DefaultLanguage: 1
  |  + Simple
  |   + Name: GENRE
  |   + String: GENRE string
  |   + TagLanguage: und
  |   + DefaultLanguage: 1
  |  + Simple
  |   + Name: TITLE
  |   + String: TITLE string
  |   + TagLanguage: und
  |   + DefaultLanguage: 1
  |  + Simple
  |   + Name: ALBUM
  |   + String: ALBUM string
  |   + TagLanguage: und
  |   + DefaultLanguage: 1
  |  + Targets
  |   + TrackUID: 3391929919
  |   + TargetTypeValue: 50
  Statistics for track number 1: number of blocks: 26; size in bytes: 1768432;
  duration in seconds: 5.2; approximate bitrate in bits/second: 2720667

4) However, gst-launch found the tags GENRE, TITLE and ALBUM only.
It seems that matroskademux could not find the ARTIST tag.

  % gst-launch -t filesrc location=./test.mkv ! matroskademux ! fakesink
  Setting pipeline to PAUSED ...
  Pipeline is PREROLLING ...
  FOUND TAG      : found by element "matroskademux0".
       audio codec: Raw 16-bit PCM audio
     language code: und
  FOUND TAG      : found by element "matroskademux0".
             genre: GENRE string
             title: TITLE string
             album: ALBUM string
  container format: Matroska
  Pipeline is PREROLLED ...
  Setting pipeline to PLAYING ...
  New clock: GstSystemClock
  Got EOS from element "pipeline0".
  Execution ended after 5711643 ns.
  Setting pipeline to PAUSED ...
  Setting pipeline to READY ...
  Setting pipeline to NULL ...
  Freeing pipeline ...


According to the Matroska Tag Specifications[1], ARTIST tag is listed in the Official tags category.
It would be nice if matroskademux can read the ARTIST tag.
[1] Tag Specifications | Matroska
    http://www.matroska.org/technical/specs/tagging/index.html

I also tested with gstreamer 0.10.32, but the problem seems not be fixed.

Regards,