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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.

• How can I encode RGB images into HDR10 videos in ffmpeg command-line ? [closed]

  5 juin 2024, par F.X.

  How can I encode HDR10 videos from RGB images using the ffmpeg command-line, with the proper color and luminance metadata ?

  


  There are a lot of ffmpeg command-line examples floating around when searching information about how to encode HDR10 streams properly, but I didn't find any that has a comprehensive list of all the parameters you can tune when using RGB frames as inputs.

  


  For example :

  


  

  • This article has a lot of information, but uses an existing video as input.

  


  • Similarly, this article uses an existing video as input

  


  


• avcodec/dpx : Move need_align to act per line

  14 novembre 2015, par Michael Niedermayer

  avcodec/dpx : Move need_align to act per line
  Fixes out of array read
  
  Fixes : 61cf123c081ee2bb774d307c75bdb99e/asan_heap-oob_1224f76_5546_bee833ffae73f752b489b9eeaac52db7.dpx
  Found-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/dpx.c