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• How To Play Hardware Accelerated Video on A Mac

  28 mai 2013, par Multimedia Mike — General

  I have a friend who was considering purchasing a Mac Mini recently. At the time of this writing, there are 3 desktop models (and 2 more “server” models).

  
  
  

  The cheapest one is a Core i5 2.5 GHz. Then there are 2 Core i7 models : 2.3 GHz and 2.6 GHz. The difference between the latter 2 is US$100. The only appreciable technical difference is the extra 0.3 GHz and the choice came down to those 2.

  He asked me which one would be able to play HD video at full frame rate. I found this query puzzling. But then, I have been “in the biz” for a bit too long. Whether or not a computer or device can play a video well depends on a lot of factors.

  Hardware Support
  First of all, looking at the raw speed of the general-purpose CPU inside of a computer as a gauge of video playback performance is generally misguided in this day and age. In general, we have a video standard (H.264, which I’ll focus on for this post) and many bits of hardware are able to accelerate decoding. So, the question is not whether the CPU can decode the data in real time, but can any other hardware in the device (likely the graphics hardware) handle it ? These machines have Intel HD 4000 graphics and, per my reading of the literature, they are capable of accelerating H.264 video decoding.

  Great, so the hardware supports accelerated decoding. So it’s a done deal, right ? Not quite…

  Operating System Support
  An application can’t do anything pertaining to hardware without permission from the operating system. So the next question is : Does Mac OS X allow an application to access accelerated video decoding hardware if it’s available ? This used to be a contentious matter (notably, Adobe Flash Player was unable to accelerate H.264 playback on Mac in the absence of such an API) but then Apple released an official API detailed in Technical Note TN2267.

  So, does this mean that video is magically accelerated ? Nope, we’re still not there yet…

  Application Support
  It’s great that all of these underlying pieces are in place, but if an individual application chooses to decode the video directly on the CPU, it’s all for naught. An application needs to query the facilities and direct data through the API if it wants to leverage the acceleration. Obviously, at this point it becomes a matter of “which application ?”

  My friend eventually opted to get the pricier of the desktop Mac Mini models and we ran some ad-hoc tests since I was curious how widespread the acceleration support is among Mac multimedia players. Here are some programs I wanted to test, playing 1080p H.264 :

  • Apple QuickTime Player
  • VLC
  • YouTube with Flash Player (any browser)
  • YouTube with Safari/HTML5
  • YouTube with Chrome/HTML5
  • YouTube with Firefox/HTML5
  • Netflix

  I didn’t take exhaustive notes but my impromptu tests revealed QuickTime Player was, far and away, the most performant player, occupying only around 5% of the CPU according to the Mac OS X System Profiler graph (which is likely largely spent on audio decoding).

  VLC consistently required 20-30% CPU, so it’s probably leveraging some acceleration facilities. I think that Flash Player and the various HTML5 elements performed similarly (their multi-process architectures can make such a trivial profiling test difficult).

  The outlier was Netflix running in Firefox via Microsoft’s Silverlight plugin. Of course, the inner workings of Netflix’s technology are opaque to outsiders and we don’t even know if it uses H.264. It may very well use Microsoft’s VC-1 which is not a capability provided by the Mac OS X acceleration API (it doesn’t look like the Intel HD 4000 chip can handle it either). I have never seen any data one way or another about how Netflix encodes video. However, I was able to see that Netflix required an enormous amount of CPU muscle on the Mac platform.

  Conclusion
  The foregoing is a slight simplification of the video playback pipeline. There are some other considerations, most notably how the video is displayed afterwards. To circle back around to the original question : Can the Mac Mini handle full HD video playback ? As my friend found, the meager Mac Mini can do an admirable job at playing full HD video without loading down the CPU.

• How to create video and audio files for the Media Source Extension API ?

  5 décembre 2018, par Aman

  I have created a video player from the Media Source Extension API. I have split the video and audio from the original.mp4 (1 minute duration). I have split the video and audio into small 5 second files (12 files in total). I’m getting each one of them and playing them together. But the video stops playing at around 45-47 seconds. I cannot understand to why the video is stopping/buffering. I cannot understand whether the problem is in the javascript code or the video files ?

  I have uploaded all the resources here (https://drive.google.com/file/d/1NHc_yNRU0tvaU18aohLy74Js3y7UHD4N/view?usp=sharing). And written the commands I used to construct my video and audio files below. I have also noticed that this problem only occurs with Google Chrome and works perfectly and smoothly on Microsoft Edge. Thanks

  Making the Media files:

  Extracting video from original.mp4: MP4Box -single 1 original.mp4

  Extracting audio from original.mp4: MP4Box -single 2 original.mp4

  Splitting the video and audio into 5 second parts: ffmpeg -ss starting-time -to end-time -i (video.mp4 OR audio.mp4) (video_part.mp4 OR audio_part.mp4)

  Fragmenting all the video and audio parts: MP4Box -dash 1000 -rap -frag-rap(video_part.mp4 OR audio_part.mp4)

  Then using the fragmented video and audio files to be played via the Media Source Extension API video player. e.g. (video_part_dashinit.mp4 OR audio_part_dashinit.mp4)

• Run ffmpeg using shell_exec from a file called by AJAX

  20 décembre 2012, par user1255617

  Good morning,

  I will do my best to phrase a "thoughtful" and "helpful" question for all regarding running FFMPEG using shell_exec from a file called by AJAX. First I will start by listing my current code.

  AJAX script

          <code class="echappe-js">&lt;script&gt;<br />
  
              var xmlhttp;<br />
  
              if (window.XMLHttpRequest){// code for IE7+, Firefox, Chrome, Opera, Safari<br />
  
                xmlhttp=new XMLHttpRequest();<br />
  
              }else{// code for IE6, IE5<br />
  
                xmlhttp=new ActiveXObject(&quot;Microsoft.XMLHTTP&quot;);<br />
  
              }<br />
  
              xmlhttp.onreadystatechange=function(){<br />
  
                if (xmlhttp.readyState==4 &amp;amp;&amp;amp; xmlhttp.status==200){<br />
  
                    //Do something<br />
  
                }<br />
  
              }<br />
  
              xmlhttp.open(&quot;GET&quot;,&quot;video_convert.php&quot;,true);<br />
  
              xmlhttp.setRequestHeader(&quot;Content-type&quot;,&quot;application/x-www-form-urlencoded&quot;);<br />
  
              xmlhttp.send(id=&amp;lt;?php echo $video_upload_result; ?&gt;);<br />
  
          &lt;/script&gt;
  
  

  PHP Code

  $destination = "files/videos/";
  
  $ffmpeg = '/ffmpeg/ffmpeg';
  
  $videoid = mysql_clean($_GET['id']);
  
  
  
  $sql = "SELECT file_name FROM cb_video WHERE videoid = '$videoid' ";
  
  $result = mysql_query($sql);
  
  $row = mysql_fetch_assoc($result);
  
  
  
  $file_old = glob('files/videos/'.$file_name.'.*');
  
  
  
  shell_exec($ffmpeg." -i '/var/www/html/".$file_old[0]."' -ar 44100 /var/www/html/".$destination.$file_name.".flv");

  FFMPEG is installed and working properly as I have used it elsewhere on the site and have attempted a file conversion using PuTTY. I am able to run a PHP file called by AJAX as I have done it in a separate instance on this site. The only thing I can think of is that the shell_exec isn't running properly, which I have used elsewhere, since it is in a separate file called by ajax or else it is being closed pre-maturely. I have also tested this code in a main file and it works properly until I try to call the separate file with it in it.

  So, my question is can this code actually work and if so what steps should I take to get it working ?

  Also I would greatly appreciate it if before closing my questions I had a chance to defend or rephrase them to properly suit this boards high standards for questions if I have somehow failed it in any way.

  Thank you.