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• reading ffmpeg output and sending it to a form

  3 juillet 2013, par Aeon2058

  I can run arguments through ffmpeg just fine, but I need to be able to read its output LIVE as it streams (as you may know, ffmpeg can take a while, and it updates its stderr twice a second with current frame, etc).

  I have a form called prog that was declared globally with ProgressForm prog = new ProgressForm(); The user inputs a folder of video files, some data is gathered, and then a button is pushed to start the encoding process with ffmpeg. The button_click event creates a new thread like so :

   runFFMpeg = new Thread(run_ffmpeg);
  
   runFFMpeg.start();

  runFFMpeg was initialized globally earlier with private Thread runFFMpeg;.

  Now I have the method run_ffmpeg :

  private void run_ffmpeg()
  
  {
  
      string program = "C:\\ffmpeg64.exe";
  
      string args = //some arguments that I know work;
  
  
  
      ProcessStartInfo run = new ProcessStartInfo(program,args);
  
      run.UseShellExecute = false;
  
      run.CreateNoWindow = true;
  
      run.RedirectStandardOutput = true;
  
      run.RedirectStandardError = true;
  
      Process runP = new Process();
  
      runP = Process.Start(run);
  
      runP.WaitForExit();
  
  
  
      //NOW WHAT?
  
  
  
   }

  I'm not sure what to do now to get the data LIVE, but if I can, I would be updating prog, which has a number of controls, including progress bars, etc. Typical output (that I'm interested in) looks like "frame= 240 fps= 12.8 q=0.0 size= 1273802kB time=00:00:08.008 bitrate=4415.2kbits/s dup=46 drop=0". I know how to parse that to get what I need, I just need that line !

• Extract every frame form a variable-frame-rate video with ffmpeg

  25 septembre 2013, par Xocoatzin

  I'm trying to extract all the frames on several videos. Those videos were captured on a camera that saves the output with a variable frame rate, thus, some frames are closer together in time than others (from 27 to 30 fps according to mediainfo)

  This frames are to be synchronized with some metadata, so I not only need to extract them but also keep the information of the [relative] time each frame of the video has been shot.

  I've been using ffmpeg to extract video frames, the challenge comes when the video frame rate is not constant any more. Any other method or program different than ffmpeg is ok as far as it can get the job done.

• How do I close a Node.js FFMPEG child process that is actively streaming from a live capture source ?

  1er juin 2013, par RickZ

  I'm new to Node.js and have figured out how to utilize child.spawn to launch an instance of FFMPEG that is being used to capture live video and send it over to Adobe Media Server via rtmp.

  Every example I've seen of FFMPEG being used in conjunction with Node.js has been with a time limited sample, so the child process closes once FFMPEG reaches the end of the file it is converting.

  In this case, there is no "end of file".

  If I instantiate :

      var ffmpeg = child.spawn('ffmpeg.exe', [args]);

  it creates the live feed.

  I have tried immediately shutting the child process down with a :

      setTimeout(function() {
  
          ffmpeg.stdin.resume();
  
          ffmpeg.stdin.write('insert command to echo q to close FFMPEG');
  
          ffmpeg.stdin.end();
  
      });

  However, that does not seem to work. I continue to see my rtmp feed on my test box.

  Is there any way to pass FFMPEG a shut down command via stdin in Node.js ?

  Thanks in advance !

  Rick