[FFmpeg-trac] #6103(undetermined:new): When trying to set the audio track metadata language to 'und' (undefined) ffmpeg switches to 'eng' (English)

[FFmpeg]

#6103: When trying to set the audio track metadata language to 'und' (undefined)
ffmpeg switches to 'eng' (English)
-------------------------------------+-------------------------------------
             Reporter:  vsanchez     |                    Owner:
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:
              Version:  unspecified  |  undetermined
             Keywords:  metadata     |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
-------------------------------------+-------------------------------------

Comment (by peter_b):

 Just ran into the same thing.
 btw: This issue also affects other "less common"
 [https://en.wikipedia.org/wiki/List_of_ISO_639-2_codes ISO639-2 codes]
 like
 "[https://www.loc.gov/standards/iso639-2/php/langcodes_name.php?code_ID=367
 qaa-qtz] (=Reserved for local use)" or
 "[https://www.loc.gov/standards/iso639-2/php/langcodes_name.php?code_ID=504
 zxx] (=No linguistic content)" for example.


 Here's a commandline and the complete, uncut console output for
 reproduction:

 {{{
 $ ffmpeg -y -f lavfi -i "sine=frequency=1000:duration=1" -c:a pcm_s16le
 -metadata:s:a:0 language=und delme.mov
 }}}

 {{{
 ffmpeg version N-92314-g323c2cf Copyright (c) 2000-2018 the FFmpeg
 developers
   built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.10) 20160609
   configuration: --prefix=/usr/local --enable-gpl --enable-nonfree
 --enable-version3 --enable-postproc --enable-ffplay --enable-swscale
 --enable-avfilter --enable-pthreads --enable-bzlib --enable-zlib --enable-
 decoder=png --enable-encoder=png --samples=../fate-suite --enable-
 libfreetype --enable-libopenjpeg --disable-decoder=jpeg2000 --enable-
 libvpx --enable-libvorbis --enable-libx264 --enable-libx265
   libavutil      56. 21.100 / 56. 21.100
   libavcodec     58. 34.100 / 58. 34.100
   libavformat    58. 19.102 / 58. 19.102
   libavdevice    58.  4.106 / 58.  4.106
   libavfilter     7. 39.100 /  7. 39.100
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
   libpostproc    55.  2.100 / 55.  2.100
 Input #0, lavfi, from 'sine=frequency=1000:duration=1':
   Duration: N/A, start: 0.000000, bitrate: 705 kb/s
     Stream #0:0: Audio: pcm_s16le, 44100 Hz, mono, s16, 705 kb/s
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_s16le (native) -> pcm_s16le (native))
 Press [q] to stop, [?] for help
 Output #0, mov, to 'delme.mov':
   Metadata:
     encoder         : Lavf58.19.102
     Stream #0:0(und): Audio: pcm_s16le (sowt / 0x74776F73), 44100 Hz,
 mono, s16, 705 kb/s
     Metadata:
       encoder         : Lavc58.34.100 pcm_s16le
 [Parsed_sine_0 @ 0x3aec580] EOF timestamp not reliable
 size=      87kB time=00:00:01.00 bitrate= 711.1kbits/s speed= 150x
 video:0kB audio:86kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 0.777778%
 }}}


 Reading the resulting file shows "eng" (English) instead of "und"
 (Undetermined)

 {{{
 $ ffprobe-git -loglevel quiet -show_entries
 stream=index,codec_name,codec_type:stream_tags=language -i delme.mov
 }}}

 {{{
 [STREAM]
 index=0
 codec_name=pcm_s16le
 codec_type=audio
 TAG:language=eng
 [/STREAM]
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/6103#comment:3>
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