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• Extract individual frames from video and pipe them to StandardOutput in FFmpeg

  13 novembre 2019, par Nicke Manarin

  I’m trying to extract frames from a video using FFmpeg. But instead of letting FFmpeg write the files to disk, I’m trying to get the frames directly from StandardOutput.

  I’m not sure if it’s feasible. I’m expecting to get each frame individually as they get decoded by reading and waiting until all frames are extracted.

  With the current code, I think that I’m getting all frames at once.

  ---

  Command

  ffmpeg -i "C:\video.mp4" -r 30 -ss 00:00:10.000 -to 00:01:20.000 -hide_banner -c:v png -f image2pipe -

  Code

  var start = TimeSpan.FromMilliseconds(SelectionSlider.LowerValue);
  
  var end = TimeSpan.FromMilliseconds(SelectionSlider.UpperValue);
  
  
  
  var info = new ProcessStartInfo(UserSettings.All.FfmpegLocation)
  
  {
  
      Arguments = $" -i \"{VideoPath}\" -r {fps} -ss {start:hh\\:mm\\:ss\\.fff} " +
  
          "-to {end:hh\\:mm\\:ss\\.fff} -hide_banner -c:v png -f image2pipe -",
  
      CreateNoWindow = true,
  
      ErrorDialog = false,
  
      UseShellExecute = false,
  
      RedirectStandardError = true,
  
      RedirectStandardOutput = true
  
  };
  
  
  
  var process = new Process();
  
  process.StartInfo = info;
  
  process.Start();
  
  
  
  while (!process.StandardOutput.EndOfStream)
  
  {
  
      if (_cancelled)
  
      {
  
          process.Kill();
  
          return;
  
      }
  
  
  
      //This returns me the entire byte array, of all frames.
  
      var bytes = default(byte[]);
  
      using (var memstream = new MemoryStream())
  
      {
  
          process.StandardOutput.BaseStream.CopyTo(memstream);
  
          bytes = memstream.ToArray();
  
      }
  
  }

  ---

  I also tried to use process.BeginOutputReadLine() and wait for each frame in OutputDataReceived. But it returns parts of each frame, like the 10 first bytes, than other 50 bytes, it’s erratic.

  Is there any way to get the frames separately via the output stream ?

• Heroku. Flask. App works correct on local machine but works incorrect on Heroku

  19 juin 2016, par andrey durov

  I use ffmpeg buildpack.
  heroku run "ffprobe http://91.192.180.66:1935/tv-channels/stream02/playlist.m3u8" works correct.

  My code :

  <?php 
  
  // require('../vendor/autoload.php');
  
  function run($url){
  
      $testArr=[];
  
      exec("timeout 20s ffprobe $url".' 2>&1',$output);
  
      foreach ($output as $i) {
  
          if (strpos($i, 'kb/s') !== false) {
  
      array_push($testArr,$i);
  
  }
  
  print_r("test<br />");
  
      }
  
      print_r($testArr);
  
      if ($testArr){
  
          return "good";
  
      }
  
      else{
  
          return "bad";
  
      }
  
  }
  
  
  
  print_r(run("http://91.192.180.66:1935/tv-channels/stream02/playlist.m3u8"));
  
  return "ok";
  
  
  
  
  
   ?>

  It works correct on local machine, and returns :

  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  test
  
  Array ( [0] => Stream #0:2: Audio: aac (LC) ([15][0][0][0] / 0x000F), 48000 Hz, stereo, fltp, 108 kb/s ) good

  On heroku it works incorrect and returns :

  test
  
  Array ( ) bad

  My Procfile :

  web: vendor/bin/heroku-php-apache2 web/

  Source :
  https://github.com/taketa/testStream.git

  I’am new in Flask and has no idea how to fix it. Very need your help
  Thanks.

• ffmpeg using php exec on korean filename exit code 1

  8 avril 2019, par Marc

  I can’t convert a video file. Example :

  exec(ffmpeg -i 01.시대조감.wmv 0001.mp4 -hide_banner, $output, $exit_code);

  Just returns exit code -1