[FFmpeg-user] Metadata issue

[Ryan Strassburg]

When copying my AVI to a WMV using ffmpeg I am trying to add the “Comments” for the file – this is the label within Windows Explorer Properties Detail file dialog.
  FFMpeg insists on changing my “comment” metadata tag to “Description”, thus I end up with a “Description” property field instead of “comment” property field which is not read since it is the wrong name.

Is there a way to stop this? You can see in the command line I create a metadata tag called “comment”, but it is encoding it as “Description” which is wrong, and I will prove it...

E:\WORK>ffmpeg -i Star.Trek.DS9.S01E01.E02.Emissary.DVDRip.DivX-SFM.avi -vcodec copy -acodec copy -metadata Title="Star
Trek DS9 #01.01 & 02" -metadata WM/Genre="Science Fiction" -metadata WM/Category="TV Series" -metadata WM/SubTitle="Emis
sary" -metadata "comment"="When the troubled Commander Sisko takes command of a surrendered space station, he learns tha
t it borders a unique stable wormhole." "Star Trek DS9 #01.01-02 Emissary.wmv"
ffmpeg version N-47062-g26c531c Copyright (c) 2000-2012 the FFmpeg developers
  built on Nov 25 2012 12:25:21 with gcc 4.7.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runtime-cpudetect --enable-avisynth --enable
-bzlib --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enab
le-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroed
inger --enable-libspeex --enable-libtheora --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li
bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --enable-zlib
  libavutil      52.  9.100 / 52.  9.100
  libavcodec     54. 77.100 / 54. 77.100
  libavformat    54. 37.100 / 54. 37.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 23.102 /  3. 23.102
  libswscale      2.  1.102 /  2.  1.102
  libswresample   0. 17.101 /  0. 17.101
  libpostproc    52.  2.100 / 52.  2.100
Input #0, avi, from 'Star.Trek.DS9.S01E01.E02.Emissary.DVDRip.DivX-SFM.avi':
  Metadata:
    encoder         : Nandub v1.0rc2
  Duration: 01:30:49.53, start: 0.000000, bitrate: 1077 kb/s
    Stream #0:0: Video: msmpeg4v3 (DIV3 / 0x33564944), yuv420p, 512x384, 23.98 fps, 23.98 tbr, 23.98 tbn, 23.98 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16, 159 kb/s
Output #0, asf, to 'Star Trek DS9 #01.01-02 Emissary.wmv':
  Metadata:
    Description     : When the troubled Commander Sisko takes command of a surrendered space station, he learns that it
borders a unique stable wormhole.
    Title           : Star Trek DS9 #01.01 & 02
    WM/Genre        : Science Fiction
    WM/Category     : TV Series
    WM/SubTitle     : Emissary
    WM/EncodingSettings: Lavf54.37.100
    Stream #0:0: Video: msmpeg4v3 (DIV3 / 0x33564944), yuv420p, 512x384, q=2-31, 23.98 fps, 1k tbn, 23.98 tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, 159 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame=130658 fps=26692 q=-1.0 Lsize=  728452kB time=01:30:49.53 bitrate=1095.0kbits/s
video:602173kB audio:105896kB subtitle:0 global headers:0kB muxing overhead 2.878781%

*****
... So I manually added to the comment tag using Windows Explorer Property dialog, then run ffmpeg against this file:
Input #0, asf, from 'Star Trek DS9 #01.01-02 Emissary.wmv':
  Metadata:
    comment         : When the troubled Commander Sisko takes command of a surrendered space station, he learns that it
borders a unique stable wormhole.
    Title           : Star Trek DS9 #01.01 & 02
    genre           : Science Fiction
    WM/Category     : TV Series
    WM/SubTitle     : Emissary
    encoder         : Lavf54.37.100
  Duration: 01:30:49.53, start: 0.000000, bitrate: 1095 kb/s
    Stream #0:0: Video: msmpeg4v3 (DIV3 / 0x33564944), yuv420p, 512x384, 23.98 tbr, 1k tbn, 1k tbc
    Stream #0:1: Audio: mp3 (U[0][0][0] / 0x0055), 48000 Hz, stereo, s16, 32 kb/s

*****
So Windows is erasing the “Description” tag and replacing it with “comment”. Windows Media Format SDK states this metadata tag is “Description” which maps from “PKEY_Comment”, in any case it would be nice to be able to force this tag to remain named as “comment” regardless.

Best Regards,
Ryan Strassburg