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• Is there a command to extract frames from a video to a txt file (binary or string) using ffmpeg ?

  1er novembre 2019, par Core taxxe

  How can you extract the frames from a video into a txt (or other) file with ffmpeg ?
  OS : Windows 10 64x
  Language : Python

  Tried extracting the frames as images but this is to slow (extracting and writing toi a single txt file)

• How to configure linking so that compiled binary finds libraries ?

  5 octobre 2015, par Jean Jordaan

  I’m compiling ffmpeg. Configuration :

   --prefix=/home/john/zope/engage/zeocluster/ffmpeg/parts/ffmpeg-build
 --extra-cflags='-I/home/john/zope/engage/zeocluster/ffmpeg/parts/x264-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/ogg-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/theora-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/lame-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/faac-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/faad-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/vpx-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/vorbis-build/include
 -I/home/john/zope/engage/zeocluster/ffmpeg/parts/ffmpeg-build/include'
 --extra-ldflags='-L/home/john/zope/engage/zeocluster/ffmpeg/parts/x264-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/ogg-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/theora-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/lame-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/faac-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/faad-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/vpx-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/vorbis-build/lib
 -L/home/john/zope/engage/zeocluster/ffmpeg/parts/ffmpeg-build/lib'

  The build completes fine, and LD_LIBRARY_PATH=./parts/ffmpeg-build/lib:./parts/x264-build/lib ./parts/ffmpeg-build/bin/ffmpeg runs the binary.

  Why is that LD_LIBRARY_PATH necessary ? Didn’t I already tell the compiler to link against these libraries ?

• Converting a binary stream to an mpegts stream

  22 décembre 2018, par John Kim

  I’m trying to create a livestream web app using NodeJS. The code I currently have emits a raw binary stream from the webcam on the client using socket IO and the node server receives this raw data. Using fluent-ffmpeg, I want to encode this binary stream into mpegts and send it to an RTMP server in real time, without creating any intermediary files. Could I somehow convert the binary stream into a webm stream and pipe that stream into an mpegts encoder in one ffmpeg command ?

  My relevant frontend client code :

  navigator.mediaDevices.getUserMedia(constraints).then(function(stream) {
  
      socket.emit('config_rtmpDestination',url);
  
      socket.emit('start','start');
  
      mediaRecorder = new MediaRecorder(stream);
  
      mediaRecorder.start(2000);
  
  
  
      mediaRecorder.onstop = function(e) {
  
          stream.stop();
  
      }
  
  
  
      mediaRecorder.ondataavailable = function(e) {
  
        socket.emit("binarystream",e.data);
  
      }
  
  }).catch(function(err) {
  
      console.log('The following error occured: ' + err);
  
      show_output('Local getUserMedia ERROR:'+err);
  
  });

  Relevant NodeJS server code :

  socket.on('binarystream',function(m){
  
      feedStream(m);
  
  });
  
  
  
  socket.on('start',function(m){
  
      ...
  
      var ops=[
  
          '-vcodec', socket._vcodec,'-i','-',
  
          '-c:v', 'libx264', '-preset', 'veryfast', '-tune', 'zerolatency',
  
          '-an', '-bufsize', '1000',
  
          '-f', 'mpegts', socket._rtmpDestination
  
      ];
  
      ffmpeg_process=spawn('ffmpeg', ops);
  
      feedStream=function(data){
  
          ffmpeg_process.stdin.write(data);
  
      }
  
      ...
  
  }

  The above code of course doesn’t work, I get these errors on ffmpeg :

  Error while decoding stream #0:1: Invalid data found when processing input
  
  [NULL @ 000001b15e67bd80] Invalid sync code 61f192.
  
  [libvpx @ 000001b15e6c5000] Failed to decode frame: Bitstream not supported by this decoder

  because I’m trying to convert raw binary data into mpegts.