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• How do I get the last line of a popen() callback in every iteration ?

  29 mai 2017, par Mike

  I’m trying to create a progress bar with FFMPEG using php and AJAX. When a user uploads a video file I want to be able to display the current percent until completion. I have managed to get everything working but I have one issue.

  The data returns what I want, but it also returns all the data from the previous iterations... like it just keeps stacking everything on top rather than flushing out the data from previous iterations. I tried to work with tail thinking it would return only the last line, but it did not return anything.

  Here is the code I’m working with :

  encode.php

  $video_path = 'test.mp4';
  
  $cmd        = 'ffmpeg -i ' . $video_path .' -y -hide_banner output.mp4 2>&1';
  
  
  
  while (@ ob_end_flush());
  
  
  
  $proc = popen($cmd, 'r');
  
  
  
  while (!feof($proc))
  
  {
  
  
  
      $file = escapeshellarg(fread($proc, 4096));
  
      //$line = `tail -n 1 $file`; // <-tried this with no luck
  
      echo fread($file, 4096) . "\n";
  
      @ flush();
  
  }
  
  return 'complete';
  
  pclose($proc);

  The above code returns :

  // first iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s
  
  
  
  // second iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s    
  
  frame=   54 fps= 12 q=29.0 size=     329kB time=00:00:00.16 bitrate=16146.6kbits/s 
  
  
  
  // third iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s    
  
  frame=   54 fps= 12 q=29.0 size=     329kB time=00:00:00.16 bitrate=16146.6kbits/s    
  
  frame=   57 fps= 11 q=29.0 size=     464kB time=00:00:00.26 bitrate=14233.2kbits/s 

  As you can see the data stacks, I need only the new line of data, not the data stacking.

  ** EDIT ** this has been marked as a duplicate, rather than me explain how it’s different, I’d like to hear how this is the same thing ? I am not writing to a log file and, like most people, do not feel that’s a good solution.

• Does simple rescaling from 1080p to frame height of 720 lead to 720p ?

  12 août 2015, par nburk

  I want to convert a 1080p to 720p and also lower resolutions eventually.

  I have been using ffmpeg for all my video processing activities so far, and would simply approach this task using the following command :

  ffmpeg -i tos.mov -vf scale=-1:720 tos_0x720.mov

  I understand that this will rescale my video to a new frame size having 720 pixels set as a fixed height and the width dynamically calculated.

  What I am not sure about are the implications regarding the quality factors of the video when using ffmpeg this way.

  1. Is it valid to assume that running this command will output a perfect HD 720p quality video ?
  2. What would be a benefit of using dedicated video conversion software to accomplish my goal compared to running the above command ?

• ffprobe failed to execute command

  31 août 2020, par Ted Bed

  I'm trying to get a frame from a video in a temp location but I get an error like this :

  


  Uncaught Alchemy\BinaryDriver\Exception\ExecutionFailureException: ffprobe failed to execute command '/usr/bin/ffprobe' '/tmp/phpfwEh9u' 


  


  Which is weird because I have another script that does the exact same thing but there is no error. Are there any reasons for why this could be happening ? Could there be any factors causing this in my script :

  


  $sec = 1;
$movie =  $filentmpname;
$thumbnail = 'thumbnail_uploads/' . $imfileid;

$ffmpeg = FFMpeg\FFMpeg::create();
$video = $ffmpeg->open($movie);
$frame = $video->frame(FFMpeg\Coordinate\TimeCode::fromSeconds($sec));
$frame->save($thumbnail);