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• FFMPEG MP4 conversion takes so long its not practical

  30 avril 2018, par Chrisco420365

  I want to start out by saying that I’m not just stating the fact that FFMPEG to MP4 conversion is so slow, but I’m hoping someone here can help me with this as I’ve searched around and haven’t really found out what to do in order to fix my problem.

  So I found a script that seems to do the job for me, it inputs several video file formats and will in turn convert to MP4 which I will later allow the web user to watch online.

  Two main things are done in this script by FFMPEG, a still image is captured in .jpg format and the video is converted to MP4. After some tweaking the script seems to work but at first I thought that it wasn’t working, that it was simply halting my server.

  Let me back up for a minute... I am using FFMPEG on my development server, which is really just my crappy laptop with XAMPP installed on Windows 10 and only 2GB of RAM. Once I have the site working perfectly I will move from my crappy laptop development environment to probably a entry level dedicated server hosting plan from Godaddy or other, since at first I expect the traffic to my website to be very low.

  The problem I am having is I am testing out the script that I will show you, and even with a 10MB video, it takes over 2 minutes to finish. Meanwhile the upload progress bar shows 100% since the upload is in fact complete, but no message for the user to know that something is going on behind the scenes. Obviously that I can figure out how to fix myself, maybe even just put a message letting them know that it will be a few minutes. When I tried a video that is 120MB, it took over 5 minutes which means I had to not only modify my php.ini file to allow for such script execution times, but it also makes it so that I can do nothing on the website while this is happening.

  Not only can I not even so much as scroll the page up or down, but if I try to open another tab and load my website it just sits there with a blank screen as if its trying to access my site. Obviously it’s because FFMPEG is using up all system resources during its conversion of the video file. If I open file explorer and click once on the video file that is being created, and continue clicking once on it I’ll see the file size of this file slowly get larger and larger, which is obvious since the file is being filled. This problem of course is with no users on it other than myself since its in its development stage, so I wonder what it will be like on a dedicated server with users online. Will the other users not be able to do anything for however many minutes until whoever is uploading a video has their video finished ?

  Should it be necessary for me to increase the max execution time in the php.ini file to more than 5 minutes for a 120MB file ? What will happen if a user tries to upload a file larger than 120MB ? Should I cut them off at 500MB perhaps ?

  I love the fact that my users will be able to upload videos and I can get thumbnails and even convert to MP4 to display using HTML5 but not thrilled if noone, including the user uploading the video, can use the site as the system resources are pegged. The last time I uploaded a video on YouTube I think I remember a message saying that it would take several minutes to finish but I don’t remember the website just completely stopping for several minutes. Perhaps this is because I’m running on my insignificant laptop ?

  While searching for answers to this I did come across some people complaining about it being slow but didn’t find any solutions and in fact don’t think I saw people saying it completely locked up the website until finished. As I said, I’d hate for others not to be able to get to my website or be kicked off simply because someone is uploading a video.

  Perhaps this is a common issue that can be resolved with a powerful enough dedicated server once I move to production ? I would greatly appreciate any and all suggestions on how to resolve this so the user may at least continue using other areas of our website, while the conversion is taking place. I can send them an alert once the conversion is finished. If there are any suggestions as to a minimum dedicated server specs that would help alleviate this from happening, I am all ears ! :) Thanks !

  Here is the script that I’m currently using :

  <?php
  
  include_once($_SERVER['DOCUMENT_ROOT'].'/includes/dbc.php');
  
  // size input prevents buffer overrun exploits.
  
     function sizeinput($input, $len){
  
          (int)$len;
  
       (string)$input;
  
       $n = substr($input, 0,$len);
  
       $ret = trim($n);
  
       $out = htmlentities($ret, ENT_QUOTES);
  
       return $out;
  
  }
  
  
  
   //Check the file is of correct format.  
  
   function checkfile($input){
  
      $ext = array('mpg', 'wma', 'mov', 'flv', 'mp4', 'avi', 'qt', 'wmv', 'rm');
  
      $extfile = substr($input['name'],-4); 
  
      $extfile = explode('.',$extfile);
  
      $good = array();
  
      $extfile = $extfile[1];
  
      if(in_array($extfile, $ext)){
  
            $good['safe'] = true;
  
           $good['ext'] = $extfile;
  
      }else{
  
            $good['safe'] = false;
  
     }
  
       return $good;
  
   }
  
  
  
   $user_id = $_SESSION['user_id'];
  
   // if the form was submitted process request if there is a file for uploading
  
   if($_POST && array_key_exists("vid_file", $_FILES)){
  
                             //$uploaddir is for videos before conversion
  
                            $uploaddir = 'temp/';
  
                             //$live_dir is for videos after converted to flv
  
          $live_dir = 'library/';
  
                              //$live_img is for the first frame thumbs.
  
          $live_img = 'thumbs/';      
  
                             $seed = time();       
  
          $upload = $seed;
  
          $uploadfile = 'temp/'.$upload.'.mp4';        
  
          $vid_title = sizeinput($_POST['vidTitle'], 50);
  
          $vid_title = sanitizeString($vid_title);
  
          $vid_desc = sizeinput($_POST['vidDesc'], 2000);
  
          $vid_desc = sanitizeString($vid_desc);
  
          $vid_cat = (int)$_POST['vidCat'];
  
          $safe_file = checkfile($_FILES['vid_file']);
  
          if($safe_file['safe'] == 1){
  
              if (move_uploaded_file($_FILES['vid_file']['tmp_name'], 'temp/'.$upload.'.mp4')) {
  
                     echo "File was successfully uploaded.<br />";
  
                      //$base = basename($uploadfile, $safe_file['ext']);
  
                      $new_file = $seed.'.mp4';
  
                      $new_image = $seed.'.jpg';
  
                      $new_image_path = "thumbs/".$seed.'.jpg';
  
                      $new_flv = "library/".$new_file;
  
                      //exec('ffmpeg -i '.$uploadfile.' -an -ss 00:00:01-r 1 -vframes 1 -f mjpeg -y '.$new_image_path);
  
                      exec('ffmpeg  -i '.$uploadfile.' -f mjpeg -vframes 1 -s 300x300 -an '.$new_image_path.'');
  
                      //ececute ffmpeg generate flv
  
                        exec('ffmpeg -i '.$uploadfile.' -f mp4 '.$new_flv);
  
                         //execute ffmpeg and create thumb
  
  
  
  
  
              echo 'Thank You For Your Video!<br />';
  
                         //create query to store video
  
  
  
          $sql = "INSERT INTO videos (`user_id`, `title`,`desc`, `file`, `thumb`) VALUES('".$user_id."','".$vid_title."','".$vid_desc."','".$new_file."','".$new_image."')";
  
  
  
  
  
                      echo '<img src="http://stackoverflow.com/feeds/tag/&#039;.$new_image_path.&#039;" style='max-width: 300px; max-height: 300px' /><br />
  
                            <h3>'.$vid_title.'</h3>';
  
                      mysqli_query($link, $sql) or die(mysqli_error($mysql));
  
               } else {
  
                      echo "Possible file upload attack!\n";
  
                      print_r($_FILES);
  
               }
  
  
  
          }else{
  
  
  
               echo 'Invalid File Type Please Try Again. You file must be of type 
  
               .mpg, .wma, .mov, .flv, .mp4, .avi, .qt, .wmv, .rm';
  
  
  
          }
  
   }
  
   ?>

• Can I know which byte range to read from a remote mp4 file for FFMpeg to decode a keyframe ?

  12 octobre 2023, par db9117

  I need to decode a of keyframe of a video file (mp4, h264 encoded). I know the timestamp of the keyframe I want to extract/decode. I want to minimize amount of data being read in memory. For this, I need to know beforehand exactly the minimal byte range I would require that encompasses this keyframe. How do I know what is the minimal byte range in the whole mp4 byte stream I need to read in order to be able to decode the keyframe ?

  


  I currently find the appropriate keyframe in the index_entries contained in the header. I get its byte position (pos attribute) and timestamp (timestamp attribute). I calculate the range as follows :

  


  startBytes : minimum of :

  


  

  1. the pos of the keyframe

  


  2. the pos of the nearest index entry in the audio stream happening at or before the keyframe's timestamp.

  


  


  This way when it's decoding the frame, if it also needs the audio content for demuxing, it would have it.

  


  endBytes : maximum of :

  


  

  1. the pos of the next frame in the video stream's index, after the keyframe

  


  2. the pos of the next frame in the audio stream's index after the timestamp of the wished keyframe.

  


  


  This way I know that I have everything up until the next frame in the index, which theoretically should be enough to decode the keyframe only.

  


  I then read the appropriate byte range.

  


  When I try to decode the frame, I run in a loop until I succeed :

  


  

  • avcodec_read_frame

  


  • avcodec_send_packet

  


  • avcodec_receive_frame

  


  


  I ignore AVERROR(EAGAIN) errors.

  


  avcodec_receive_frame fails multiple times with error AVERROR(EAGAIN) which I ignore, until it fails saying that the memory it wants to read isn't available (wants to read after endBytes). I explicitly tell it to fail if it wants to read more than it has already read.

  


  Note : for other keyframes at other positions in other videos, it sometimes succeeds (probably because the range is big enough by chance), but it fails more often than not.

  


  My question is : Why is the end of the range not enough to be able to decode only the one keyframe ? Is there any way to more precisely calculate the exact range in bytes I would need in order to decode a particular keyframe ?

  


• Révision 20668 : Amélioration du debug des traductions :

  24 juin 2013, par Eric Lupinacci

  - on normalise le nom des classes et leur coloration : vert pour les chaines ok, jaune pour les chaines provenant du module écrire et rouge pour les chaines non trouvées
  - on repère dans la bulle d’info le module qui contient la chaine traduite en le mettant entre deux étoiles
  - on évite de passer dans le traitement minimal qui enlève les underscores si on est en var_mode=traduction