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• How to detect audio sampling rate with avprobe / ffprobe ?

  8 août 2013, par Devy

  I am using libav 9.6, installed via Homebrew.

  $ avprobe -version
  
  avprobe version 9.6, Copyright (c) 2007-2013 the Libav developers
  
    built on Jun  8 2013 02:44:19 with Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn)
  
  avprobe 9.6
  
  libavutil     52.  3. 0 / 52.  3. 0
  
  libavcodec    54. 35. 0 / 54. 35. 0
  
  libavformat   54. 20. 3 / 54. 20. 3
  
  libavdevice   53.  2. 0 / 53.  2. 0
  
  libavfilter    3.  3. 0 /  3.  3. 0
  
  libavresample  1.  0. 1 /  1.  0. 1
  
  libswscale     2.  1. 1 /  2.  1. 1

  Even though the sampling rate is displayed in the stdout in the command line output, the -show_format option doesn't surface the sampling rate information for the audio file at all.

  Here is the BASH terminal output :

  $ avprobe  -v verbose -show_format -of json  sample.gsm
  
  avprobe version 9.6, Copyright (c) 2007-2013 the Libav developers
  
    built on Jun  8 2013 02:44:19 with Apple LLVM version 4.2 (clang-425.0.24)
  
  (based on LLVM 3.2svn)
  
    configuration: --prefix=/usr/local/Cellar/libav/9.6 --enable-shared
  
  --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree
  
  --enable-hardcoded-tables --enable-avresample --enable-vda --enable-gnutls
  
  --enable-runtime-cpudetect --disable-indev=jack --cc=cc --host-cflags=
  
  --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame
  
  --enable-libxvid --enable-avplay
  
    libavutil     52.  3. 0 / 52.  3. 0
  
    libavcodec    54. 35. 0 / 54. 35. 0
  
    libavformat   54. 20. 3 / 54. 20. 3
  
    libavdevice   53.  2. 0 / 53.  2. 0
  
    libavfilter    3.  3. 0 /  3.  3. 0
  
    libavresample  1.  0. 1 /  1.  0. 1
  
    libswscale     2.  1. 1 /  2.  1. 1
  
  [gsm @ 0x7f8012806600] Estimating duration from bitrate, this may be inaccurate
  
  Input #0, gsm, from 'sample.gsm':
  
    Duration: 00:03:52.32, start: 0.000000, bitrate: 13 kb/s
  
      Stream #0.0: Audio: gsm, 8000 Hz, mono, s16, 13 kb/s
  
  {  "format" : {
  
      "filename" : "sample.gsm",
  
      "nb_streams" : 1,
  
      "format_name" : "gsm",
  
      "format_long_name" : "raw GSM",
  
      "start_time" : "0.000000",
  
      "duration" : "232.320000",
  
      "size" : "383328.000000",
  
      "bit_rate" : "13200.000000"
  
    }}

  And the python code example :

  >>> filename = 'sample.gsm'
  
  >>> result = subprocess.check_output(['avprobe', '-show_format', '-of',
  
  'json', filename])
  
  avprobe version 9.6, Copyright (c) 2007-2013 the Libav developers
  
    built on Jun  8 2013 02:44:19 with Apple LLVM version 4.2
  
  (clang-425.0.24) (based on LLVM 3.2svn)
  
  [gsm @ 0x7fe0b1806600] Estimating duration from bitrate, this may be
  
  inaccurate
  
  Input #0, gsm, from 'sample.gsm':
  
    Duration: 00:03:52.32, start: 0.000000, bitrate: 13 kb/s
  
      Stream #0.0: Audio: gsm, 8000 Hz, mono, s16, 13 kb/s
  
  >>> print result
  
  {  "format" : {
  
      "filename" : "sample.gsm",
  
      "nb_streams" : 1,
  
      "format_name" : "gsm",
  
      "format_long_name" : "raw GSM",
  
      "start_time" : "0.000000",
  
      "duration" : "232.320000",
  
      "size" : "383328.000000",
  
      "bit_rate" : "13200.000000"
  
  }}

  So I am aware that sampling rate could be a stream specific display to be shown in -show_format option results. But there isn't any other options to detect the sampling rate on a specific audio stream even though it's possible to set it with -ar when re-encoding it.

  I filed a ticket to libav but I am just curious if there is any other way to extract sampling rate from libav probing utils. I appreciate the answer beforehand.

  PS : it would be the same question for the upstream project of ffmpeg (ffprobe) in this case.

• find in bash to convert files with ffmpeg - paths being changed

  20 avril 2017, par J V

  Trying to convert a bunch of files with ffmpeg and find.

  find -name "*.mkv" | while read f
  
  do ffmpeg -i "$f" -c copy -y "${f%.*}.mp4"
  
  done

  This should work right ? It results in :

  + read f
  
  + ffmpeg -i '/file.mkv' -c copy -y '/file.mp4'
  
  ffmpeg version N-61155-g61ff043 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Mar  7 2014 19:17:59 with gcc 4.8 (Debian 4.8.2-16)
  
  /file.mkv: No such file or directory

  So I naturally try sticking the missing dot in front of the variable :

  find -name "*.mkv" | while read f
  
  do ffmpeg -i ".$f" -c copy -y ".${f%.*}.mp4"
  
  done

  The result :

  + read f
  
  + ffmpeg -i '../file.mkv' -c copy -y '../file.mp4'
  
  ffmpeg version N-61155-g61ff043 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Mar  7 2014 19:17:59 with gcc 4.8 (Debian 4.8.2-16)
  
  ../file.mkv: No such file or directory

  It’s specifically removing the dot at the worst possible time. Any idea what’s causing this and how to fix it ?

  PS : -print0 in find has the same problem, and none of the files have newlines etc.

  Edit : As requested, the echo. The echo works as expected :

  find -name "*.mkv" | while read f
  
  do echo ffmpeg -i "$f" -c copy -y "${f%.*}.mp4"
  
  done
  
  
  
  + read f
  
  + echo ffmpeg -i './file.mkv' -c copy -y './file.mp4'
  
  ffmpeg -i ./file.mkv -c copy -y ./file.mp4

  Edit2 : With a file with a space and one without, the filename without is changed. If I rm the one with a space the one without works fine.

  $ ls
  
  + ls
  
  file.mkv  file two.mkv
  
  $ find -name "*.mkv" | while read f; do ffmpeg -i "$f" -c copy -y "${f%.*}.mp4"; done
  
  + find -name '*.mkv'
  
  + read f
  
  + ffmpeg -i './file two.mkv' -c copy -y './file two.mp4'
  
  ffmpeg version N-61155-g61ff043 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Mar  7 2014 19:17:59 with gcc 4.8 (Debian 4.8.2-16)
  
    configuration: --arch=amd64 --enable-pthreads --enable-libopencv --enable-librtmp --enable-libopenjpeg --enable-libopus --enable-libspeex --enable-libtheora --enable-vaapi --enable-runtime-cpudetect --enable-libvorbis --enable-zlib --enable-swscale --enable-libcdio --enable-bzlib --enable-libdc1394 --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-libpulse --enable-vdpau --enable-libvpx --enable-gpl --enable-x11grab --enable-libx264 --enable-filters
  
    libavutil      52. 66.101 / 52. 66.101
  
    libavcodec     55. 52.102 / 55. 52.102
  
    libavformat    55. 33.101 / 55. 33.101
  
    libavdevice    55. 11.100 / 55. 11.100
  
    libavfilter     4.  3.100 /  4.  3.100
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 18.100 /  0. 18.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Input #0, matroska,webm, from './file two.mkv':
  
    Metadata:
  
      COMPATIBLE_BRANDS: isommp42
  
      MAJOR_BRAND     : mp42
  
      MINOR_VERSION   : 0
  
      ENCODER         : Lavf55.33.101
  
    Duration: 00:08:15.54, start: 0.000000, bitrate: 194 kb/s
  
      Stream #0:0(und): Audio: aac, 44100 Hz, stereo, fltp (default)
  
      Metadata:
  
        CREATION_TIME   : 2014-03-07 04:33:17
  
        LANGUAGE        : und
  
        HANDLER_NAME    : IsoMedia File Produced by Google, 5-11-2011
  
  Output #0, mp4, to './file two.mp4':
  
    Metadata:
  
      COMPATIBLE_BRANDS: isommp42
  
      MAJOR_BRAND     : mp42
  
      MINOR_VERSION   : 0
  
      encoder         : Lavf55.33.101
  
      Stream #0:0(und): Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, stereo (default)
  
      Metadata:
  
        CREATION_TIME   : 2014-03-07 04:33:17
  
        LANGUAGE        : und
  
        HANDLER_NAME    : IsoMedia File Produced by Google, 5-11-2011
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  size=   11698kB time=00:08:15.53 bitrate= 193.4kbits/s    
  
  video:0kB audio:11614kB subtitle:0 data:0 global headers:0kB muxing overhead 0.724668%
  
  + read f
  
  + ffmpeg -i /file.mkv -c copy -y /file.mp4
  
  ffmpeg version N-61155-g61ff043 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Mar  7 2014 19:17:59 with gcc 4.8 (Debian 4.8.2-16)
  
    configuration: --arch=amd64 --enable-pthreads --enable-libopencv --enable-librtmp --enable-libopenjpeg --enable-libopus --enable-libspeex --enable-libtheora --enable-vaapi --enable-runtime-cpudetect --enable-libvorbis --enable-zlib --enable-swscale --enable-libcdio --enable-bzlib --enable-libdc1394 --enable-frei0r --enable-gnutls --enable-libgsm --enable-libmp3lame --enable-libpulse --enable-vdpau --enable-libvpx --enable-gpl --enable-x11grab --enable-libx264 --enable-filters
  
    libavutil      52. 66.101 / 52. 66.101
  
    libavcodec     55. 52.102 / 55. 52.102
  
    libavformat    55. 33.101 / 55. 33.101
  
    libavdevice    55. 11.100 / 55. 11.100
  
    libavfilter     4.  3.100 /  4.  3.100
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 18.100 /  0. 18.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  /file.mkv: No such file or directory
  
  + read f

• RTMPE FFMPEG on Linux [on hold]

  31 août 2015, par user3317118

  I’m getting download on Windows but on Linux can not, gives this error.
  [![enter image description here][1]][1]

  bebetoalves: ~/Web $ ffmpeg -f concat -i ep.txt -codec copy theroyalrangers.mkv  

  ffmpeg version 2.7.2 Copyright (c) 2000-2015 the FFmpeg developers
  built with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  configuration : —disable-yasm

  libavutil 54. 27.100 / 54. 27.100
  libavcodec 56. 41.100 / 56. 41.100
  libavformat 56. 36.100 / 56. 36.100
  libavdevice 56. 4.100 / 56. 4.100
  libavfilter 5. 16.101 / 5. 16.101
  libswscale 3. 1.101 / 3. 1.101
  libswresample 1. 2.100 / 1. 2.100

  [concat @ 0x1bf4260] Impossible to open ’rtmpe ://viacomnickstrmfs.fplive.net/viacomnickstrm/gsp.alias/me
  diabus/kids.com/2015/08/26/11/22/23884690/HDXPR510A1_884690_5801915_1280x720_3500_h32.mp4’

  ep.txt : Protocol not found
  bebetoalves : /Web $