Recherche avancée

Sur d’autres sites (16547)

• How do I end s pipe ?

  5 septembre 2019, par Leo

  I have trouble using ’ffprobe’ from node.js. I need the audio lengths MP3 files. There is an npm package, ’get-audio-duration’ for this.

  The package calls ’ffprobe’ through an ’execa’ command. It works well for .flac files both when when using a filename and a stream. However for .mp3 files it fails for streams.

  I suspected some problems with ’execa’ so I checked from the command line (on Windows 10) :

  type file.mp3 | ffprobe -

  (Where I left out the parameters to ffprobe for clarity.)

  This kind of works, but says duration=N/A.

  It looks to me like ffprobe didn’t get the info that the input is finished. Or, it dint care about it. (There is a 4 year old bug report about this on the ffmpeg issue site which was closed for no obvious reason.)

  Is it possible to somehow tell ffprobe that the pipe has ended ?

• FFMPEG - Pipe PCM to STDOUT in real-time for Node.js

  20 août 2019, par bloom.510

  I am able to stream realtime PCM data from my system’s loopback driver that I can either encode raw or in WAV format using FFMPEG.

  How can I pipe the PCM to stdout as its being recorded in real-time ?

  I’m batting around in the dark here. So far I’ve tried logging stdout in Node.js, as well as creating a named pipe and listening for changes to it. None of these has returned any output.

  The basic shell command captures the audio :

  ffmpeg -f alsa -i loopout -f s16le -acodec pcm_s16le out.raw

  Using child_process.spawn() in Node.js :

  let ffmpeg = spawn('ffmpeg', [
  
      '-f', 'alsa', '-ac', '2', '-ar', '44100', '-i',
  
      'loopout', '-f', 's16le', '-acodec', 'pcm_s16le', 'out.raw',
  
  ]);

  However :

  // this never logs anything
  
  ffmpeg.stdout.on('data', (data) => {
  
      console.log(data.toString());
  
  });
  
  
  
  // this outputs what you would see in the terminal window
  
  ffmpeg.stderr.on('data', (data) => {
  
      console.log(data.toString());
  
  });

  Is there a way to access a readable stream of this file as its being created ?

  Or perhaps there is a way to stream the PCM to an RTP server and forward it as a buffer over UDP to an Express server ?

  Whatever the methodology is, the ultimate goal is to access it as a stream in Node.js and convert it into an ArrayBuffer.

• Pipe FFMPEG MPEG-DASH livestream to AWS S3

  17 août 2019, par Alexander

  So I’m currently trying to livestream the rendering of a GPU-heavy video (renders about 1fps), encode it to a 30fps MPEG-DASH livestream and output this to AWS S3 so Shaka Player can display the live rendering.

  The first issue is that the livestream keeps looping, it doesn’t stop after the rendering for loop is done.

  I use a python script to pipe the output of the rendering to FFMPEG, and pipe the output of FFMPEG to the aws s3 cli like this :

  p1 = Popen(['ffmpeg', '-y', '-hwaccel', 'cuvid', '-f', 'image2pipe', '-r', '24', '-i', '-', '-c:v', 'h264_nvenc', '-b:v', '5M', '-f', 'dash', '-movflags', 'frag_keyframe+empty_moov', '-'], stdin=PIPE)#, shell=True) #'-method', 'PUT', 'https://example.s3.amazonaws.com/test1/test1.mpd'], stdin=PIPE)
  
  
  
  p2 = Popen(['aws', 's3', 'cp', '-', 's3://example/test1/test1.mpd'], stdin=p1.stdout)
  
  
  
  
  
  #The following commented aws s3 sync command uploads successfully to S3
  
  #but the issue here is that it stops after the syncing is done and its hacky
  
  #p1 = Popen(['ffmpeg', '-y', '-vsync', '0', '-hwaccel', 'cuvid', '-f', 'image2pipe', '-r', '24', '-i', '-', '-c:v', 'h264_nvenc', '-b:v', '5M', '-f', 'dash', '-movflags', 'frag_keyframe+empty_moov', 'test2.mpd'], stdin=PIPE)#, shell=True) #'-method', 'PUT', 'https://teststream.s3.amazonaws.com/test1/test1.mpd'], stdin=PIPE)
  
  #p2 = Popen(['aws', 's3', 'sync', '.', 's3://teststream/test1', '--exclude', '"*"', '--include', '"*.m4s"', '--include', '"*.mpd"'], stdin=PIPE)
  
  
  
  #pseudocode
  
  for ci,(content,contentName) in enumerate(content_loader):
  
      im = renderframe(content)
  
      im.save(p1.stdin, 'PNG')
  
  
  
  p1.stdin.close()
  
  p1.wait()
  
  p2.stdin.close()
  
  p2.wait()