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• Why does HTML5 video with very large h.264 encoded mp4 (with +faststart, ie metadata at beginning), take ages to load ?

  15 septembre 2015, par Tom Jenkinson

  The video is rendered with ffmpeg with the "faststart" flag added meaning the metadata should be at the start of the file, and the server appears to be handling partial content requests correctly, so why does it need to have downloaded so much of the video before the player becomes enabled and can play the video ? I am testing it in Google Chrome.

  Once the player becomes enabled I can seek around to various points in the video pretty instantly and see the new partial content requests being made.

  Here is a link to the video : http://iptv.la1tv.co.uk/unibrass.mp4

  Here is a jsbin with the video tag : https://jsbin.com/rahewidoru . It takes a few minutes but does work after it loads.

  Any suggestions ?

  I realise there are other methods like HLS and dash which use chunks, but I would like to know why it isn’t working this way because I can’t find anywhere that provides a reason as to why it doesn’t work well.

• Seeking with the activeX VLC plugin has a bad response rate

  24 juin 2017, par Vitalis Hommel

  I am using axVLCPlugin.input.time = pos; where pos is the new time to browse through a video clip in small resolution (240p) in a VLC activeX part of my program using a slider, which updates pos.

  On an older laptop this worked flawlessly, with no delay. On my new laptop, this works only with significant delay, meaning that once I enter a new position, it takes about 1 second to show this position of the video on screen in the VLC activeX plugin. Previously it was instant.

  Is this

  1. a VLC issue(2.2.6 umbrella) ?
  2. a Visual Studio issue(VS 2017) ?
  3. a video encoding issue(ffmpeg version N-86482-gbc40674 - ffmpeg -i inputfile.extension output.mp4) ?
  4. a video codec issue ?

  EDIT : fortunately I found that the activex-plugin has an output. This is what it gives me : https://pastebin.com/GEKb22Gg - still unclear what that means

  How to track down the cause and solve it ?

• ffmpeg not returning duration, cant play video until complete. Stream images 2 video via PHP

  17 février 2014, par John J

  I am real struggling with ffmpeg. I am trying to convert images to video, I have an ip camera which I am recording from. The recordings are mjpegs 1 frame per image.

  I am trying to create a script in php so I can recreate a video from date to date, this requires inputting the images via image2pipe and then creating the video.

  The trouble is, ffmpeg does return the duration and start stats, so I have no way of working out when the video is done or what percentage is done. The video won't play until its finished, and its not a very good UE.

  Any ideas of how I can resolve this, the video format can be anything I am open to suggestions.

  PHP :

  //Shell command
  
  exec('cat /image/dir/*.jpg | ffmpeg -y -c:v mjpeg -f image2pipe -r 10 -i - -c:v libx264 -pix_fmt yuv420p -movflags +faststart myvids/vidname.mp4 1>vidname.txt 2>&1')
  
  
  
  //This is loaded via javascript when the video is loaded (which is failing due to stats being wrong
  
  $video_play = "<video width="\&quot;320\&quot;" height="\&quot;240\&quot;" src="\&quot;myvids/vidname.mp4\&quot;" type="\&quot;video/mp4\&quot;\" controls="\&quot;controls\&quot;" preload="\&quot;none\&quot;"></video>";

  Javascript :

  //Javascript to create the loop until video is loaded
  
  <code class="echappe-js">&lt;script&gt;<br />
  
             $(document).ready(function() {<br />
  
                  var loader = $(&quot;#clip_load&quot;).percentageLoader();<br />
  
                  $.ajaxSetup({ cache: false }); // This part addresses an IE bug. without it, IE will only load the first number and will never refresh<br />
  
                  var interval = setInterval(updateProgress,1000);<br />
  
                  function updateProgress(){ $.get( &quot;&amp;#39;.base_url().&amp;#39;video/getVideoCompile_Process?l=&amp;#39;.$vid_name.&amp;#39;-output.txt&amp;amp;t=per&quot;, function( data ) { if(data=&gt;\&amp;#39;100\&amp;#39;){ $(&quot;#clip_load&quot;).html(\&amp;#39;&amp;#39;.$video_play.&amp;#39;\&amp;#39;); clearInterval(interval); }else{loader.setProgress(data); } });                    }<br />
  
              });<br />
  
              &lt;/script&gt;
  
  

  PHP (page is called via javascript :

  //This is the script which returns the current percentage
  
  $logloc = $this->input->get('l');
  
  $content = @file_get_contents($logloc);
  
  
  
  if($content){
  
      //get duration of source
  
      preg_match("/Duration: (.*?), start:/", $content, $matches);
  
  
  
      $rawDuration = $matches[1];
  
  
  
      //rawDuration is in 00:00:00.00 format. This converts it to seconds.
  
      $ar = array_reverse(explode(":", $rawDuration));
  
      $duration = floatval($ar[0]);
  
      if (!empty($ar[1])) $duration += intval($ar[1]) * 60;
  
      if (!empty($ar[2])) $duration += intval($ar[2]) * 60 * 60;
  
  
  
      //get the time in the file that is already encoded
  
      preg_match_all("/time=(.*?) bitrate/", $content, $matches);
  
  
  
      $rawTime = array_pop($matches);
  
  
  
      //this is needed if there is more than one match
  
      if (is_array($rawTime)){$rawTime = array_pop($rawTime);}
  
  
  
      //rawTime is in 00:00:00.00 format. This converts it to seconds.
  
      $ar = array_reverse(explode(":", $rawTime));
  
      $time = floatval($ar[0]);
  
      if (!empty($ar[1])) $time += intval($ar[1]) * 60;
  
      if (!empty($ar[2])) $time += intval($ar[2]) * 60 * 60;
  
  
  
      //calculate the progress
  
      $progress = round(($time/$duration) * 100);
  
      if ($this->input->get('t')=='per'){
  
          echo $progress;
  
      }else{
  
              echo "Duration: " . $duration . "<br />";
  
              echo "Current Time: " . $time . "<br />";
  
      echo "Progress: " . $progress . "%";}
  
  }else{ echo "cannot locate";}

  Thanks