[FFmpeg-trac] #5121(undetermined:new): Wrong sample rate read from / written to opus webm file

[FFmpeg]

#5121: Wrong sample rate read from / written to opus webm file
-------------------------------------+-------------------------------------
             Reporter:  pszemus      |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 As reported in https://bugzilla.mozilla.org/show_bug.cgi?id=1227153 trying
 to create a 24kHz opus at webm file produces a file that has 48kHz written to
 an opus header (?). What's strange is that MediaInfo shows this sample
 rate correctly.

 How to reproduce:
 {{{
 $ ffmpeg -i
 http://www.soundsnap.com/audio/play/72210%3A1448291371%3Ab4326304c013a3a61b3b87d83158c91b
 -c:a libopus -b:a 64k -ar 24000 /tmp/tmp.webm
 ffmpeg version N-77704-g68eb208 Copyright (c) 2000-2016 the FFmpeg
 developers
   built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-4)
   configuration: --prefix=/home/pszemus/ffmpeg/build --enable-pic
 --enable-pthreads --enable-libmp3lame --enable-version3 --enable-libfaac
 --enable-gpl --enable-nonfree --enable-libvpx --enable-libvorbis --enable-
 libopus --enable-libx264 --enable-libwebp --enable-protocol=https
 --enable-openssl --extra-cflags=-I/opt/WP/common.libs/include --extra-
 ldflags='-L/opt/WP/common.libs/lib -ldl'
   libavutil      55. 12.100 / 55. 12.100
   libavcodec     57. 21.100 / 57. 21.100
   libavformat    57. 21.100 / 57. 21.100
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6. 23.100 /  6. 23.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
 [mp3 @ 0x2ae63a0] Skipping 0 bytes of junk at 0.
 [mp3 @ 0x2ae63a0] Estimating duration from bitrate, this may be inaccurate
 Input #0, mp3, from
 'http://www.soundsnap.com/audio/play/72210%3A1448291371%3Ab4326304c013a3a61b3b87d83158c91b':
   Metadata:
     title           : PleaseRefesh2015_1
     date            : 2015
     track           : 1
   Duration: 00:00:04.13, start: 0.000000, bitrate: 192 kb/s
     Stream #0:0: Audio: mp3, 44100 Hz, stereo, s16p, 192 kb/s
 Output #0, webm, to '/tmp/tmp.webm':
   Metadata:
     title           : PleaseRefesh2015_1
     date            : 2015
     track           : 1
     encoder         : Lavf57.21.100
     Stream #0:0: Audio: opus (libopus), 24000 Hz, stereo, s16, 64 kb/s
     Metadata:
       encoder         : Lavc57.21.100 libopus
 Stream mapping:
   Stream #0:0 -> #0:0 (mp3 (native) -> opus (libopus))
 Press [q] to stop, [?] for help
 size=      37kB time=00:00:04.13 bitrate=  73.7kbits/s speed=15.4x
 video:0kB audio:35kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 5.376523%
 }}}
 {{{
 $ ffmpeg -i /tmp/tmp.webm
 ffmpeg version N-77704-g68eb208 Copyright (c) 2000-2016 the FFmpeg
 developers
   built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-4)
   configuration: --prefix=/home/pszemus/ffmpeg/build --enable-pic
 --enable-pthreads --enable-libmp3lame --enable-version3 --enable-libfaac
 --enable-gpl --enable-nonfree --enable-libvpx --enable-libvorbis --enable-
 libopus --enable-libx264 --enable-libwebp --enable-protocol=https
 --enable-openssl --extra-cflags=-I/opt/WP/common.libs/include --extra-
 ldflags='-L/opt/WP/common.libs/lib -ldl'
   libavutil      55. 12.100 / 55. 12.100
   libavcodec     57. 21.100 / 57. 21.100
   libavformat    57. 21.100 / 57. 21.100
   libavdevice    57.  0.100 / 57.  0.100
   libavfilter     6. 23.100 /  6. 23.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
 Input #0, matroska,webm, from '/tmp/tmp.webm':
   Metadata:
     title           : PleaseRefesh2015_1
     encoder         : Lavf57.21.100
   Duration: 00:00:04.14, start: 0.007000, bitrate: 73 kb/s
     Stream #0:0: Audio: opus, 48000 Hz, stereo, fltp (default)
 At least one output file must be specified
 }}}
 {{{
 $ mediainfo /tmp/tmp.webm
 General
 Unique ID                                :
 23699742163318188445154506414781705045
 (0x11D46780E7425B3B392AC806ACE92B55)
 Complete name                            : /tmp/tmp.webm
 Format                                   : WebM
 Format version                           : Version 4 / Version 2
 File size                                : 37.2 KiB
 Duration                                 : 4s 135ms
 Overall bit rate                         : 73.6 Kbps
 Track name                               : PleaseRefesh2015_1
 Writing application                      : Lavf57.21.100
 Writing library                          : Lavf57.21.100

 Audio
 ID                                       : 1
 Format                                   : Opus
 Codec ID                                 : A_OPUS
 Duration                                 : 4s 135ms
 Channel(s)                               : 2 channels
 Channel positions                        : Front: L R
 Sampling rate                            : 24.0 KHz
 Bit depth                                : 16 bits
 Compression mode                         : Lossy
 Default                                  : Yes
 Forced                                   : No
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/5121>
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