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• FFMpeg Concatenation Filters : Stream specifier ':0' in filtergraph matches no streams

  7 février 2017, par Anthony Eden

  I am developing an application that relies heavily on FFMpeg to perform various transformations on audio files. I am currently testing my FFMpeg configuration on the command line.

  I am trying to concatenate multiple audio files which are in different formats (Primarily MP3, MP2 & WAV). I have been using the official TRAC documentation (https://trac.ffmpeg.org/wiki/How%20to%20concatenate%20(join%2C%20merge)%20media%20files#differentcodec) to help me with this and have created the following command :

  ffmpeg -i OHIn.wav -i OHOut.wav -filter_complex '[0:0] [1:0] concat=n=2:a=1 [a]' -map '[a]' output.wav

  However, when I run this on Mac OS X using version 2.0.1 of FFMpeg, I get the following error message :

  Stream specifier ':0' in filtergraph description [0:0] [1:0] concat=n=2:a=1 [a] matches no streams.

  Here is my full output from the terminal :

  ~/ffmpeg -i OHIn.wav -i OHOut.wav -filter_complex '[0:0] [1:0] concat=n=2:a=1 [a]' -map '[a]' output.wav
  
  
  
  ffmpeg version 2.0.1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Aug 15 2013 10:56:46 with llvm-gcc 4.2.1 (LLVM build 2336.11.00)
  
    configuration: --prefix=/Volumes/Ramdisk/sw --enable-gpl --enable-pthreads --enable-version3 --enable-libspeex --enable-libvpx --disable-decoder=libvpx --enable-libmp3lame --enable-libtheora --enable-libvorbis --enable-libx264 --enable-avfilter --enable-libopencore_amrwb --enable-libopencore_amrnb --enable-filters --enable-libgsm --arch=x86_64 --enable-runtime-cpudetect
  
    libavutil      52. 38.100 / 52. 38.100
  
    libavcodec     55. 18.102 / 55. 18.102
  
    libavformat    55. 12.100 / 55. 12.100
  
    libavdevice    55.  3.100 / 55.  3.100
  
    libavfilter     3. 79.101 /  3. 79.101
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  
  Input #0, wav, from 'OHIn.wav':
  
    Duration: 00:00:06.71, bitrate: 1411 kb/s
  
      Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  Guessed Channel Layout for  Input Stream #1.0 : stereo
  
  Input #1, wav, from 'OHOut.wav':
  
    Duration: 00:00:07.19, bitrate: 1411 kb/s
  
      Stream #1:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  Stream specifier ':0' in filtergraph description [0:0] [1:0] concat=n=2:a=1 [a] matches no streams.

  I do not understand why this does not work. FFMpeg shows that the streams 0:0 and 1:0 exist in the source files. The only other similar problems online have surrounded the use of the single quote in Windows, however testing of this confirm it does not apply to my Mac command line.

  Any help would be much appreciated.

• node.js live streaming ffmpeg stdout to res

  24 mai 2014, par blasteye

  I want node.js to convert an extremly long audio file to mp3, and the second data is available on stdout, node.js should send it to the client for them to play.

  I’ve written the following, and while it works, the html5 audio/video tag waits until ffmpeg is 100% done transcoding, where-as I want to start playing the video while ffmpeg is doing its thing.

  var ffmpeg = childProcess.spawn('ffmpeg', [
  
     '-i', params.location, //location of the specified media file
  
     '-f', 'mp3',
  
     'pipe:1'
  
   ]);
  
   res.writeHead(200, {
  
     'Content-Type': 'audio/mp3'
  
   });
  
   ffmpeg.stdout.pipe(res);

  EDIT 1 : Not sure why, but if params.location points to a movie everything seems to work. But if its an audio file, ffmpeg doesn’t seem to be outputting to stdout until its 100% converted.

  EDIT 2 : Turns out that you can’t dump an mp4 file to stdout due to the fact that mp4 files are non Causal (http://en.wikipedia.org/wiki/Causal_system). THerefore if you use webm it works. Just make sure to compile ffmpeg with webm support (for homebrew users : brew install ffmpeg —with-vpx —with-vorbis ).

  I’ve uploaded a github gist showing two functions to send live mp3/webm transcodes : https://gist.github.com/cobookman/c1a9856a4588496b021a

• ffmpegthumbnailer issue : dyld : Library not loaded : /usr/local/lib/libavutil.52.18.100.dylib

  18 octobre 2013, par scientiffic

  When I try to run ffmpegthumbnailer, I get the following error :

  dyld: Library not loaded: /usr/local/lib/libavutil.52.18.100.dylib
  
    Referenced from: /usr/local/bin/ffmpegthumbnailer
  
    Reason: image not found
  
    Trace/BPT trap: 5

  I installed ffmpeg using the directions here :

  http://ffmpeg.org/trac/ffmpeg/wiki/MacOSXCompilationGuide

  In my /usr/local/lib folder, I have the file "libavutil.a", but not the one specified in the error mesage.

  How can I solve this error ?

  This is what I was using to try to generate a thumbnail :

  ffmpegthumbnailer -i /public/uploads/tmp/1382121359-37490-7826/thumb_Untitled.mov -o /public/uploads/tmp/1382121359-37490-7826/tmpfile.png -c png -q 10 -s 158