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• PHP and ffmpeg - Converting to H.264 on the fly for JW Player

  10 mai 2012, par vertigoelectric

  So the project I'm working on has tons of MP4 files already on the server that need to be played in an embedded player. Ideally we'd like to use the JW Player which is already set up for most of the videos. Unfortunately, a lot of the older videos are MPEG-4 encoded and require additional plugins to play in the browser.

  What I'd like to do is be able to transcode these videos on the fly to a format that JW Player supports, such as H.264. Now, I'm part way there because I can get it to convert the old MP4 files, but I'm having difficulty passing the data directly to the player.

  This is my current script doing the converting (this is media_converted.php) :

  <?php
  
      error_reporting(0);
  
      if (!isset($_GET["MediaName"])) {
  
          $_GET["MediaName"] = "GSX238";
  
      }       
  
      require_once("php/media_center_functions.php");
  
      $MediaURL = ConstructVideoURLInternap($_GET["MediaName"]);  
  
      header("Content-Transfer-Encoding: binary");
  
      //header('Content-type: video/mp4');
  
      //$calculatedFileSize = filesize($MediaURL);
  
      //header("Content-Length: {$calculatedFileSize}");
  
  
  
      $cmd = 'ffmpeg -i "'.$MediaURL.'"  -vcodec libx264 -acodec copy -f mp4  -moov_size 32000 "_temp/'.time().'_temp.mp4"  2> _temp/media_converter_output.txt';
  
      passthru($cmd);
  
  
  
  ?>

  I'm trying to take the above file and pass it to the JW Player as the video source : in the JW Player's variable scripting, like so :

  so.addVariable('file','media_converted.php?MediaName=12345');

  While I believe this should work, it's just not.

  Even when the conversion seems to work and be sending to the player, it's hard to tell because I think the browser is trying to download the entire file before playing anything. Obviously I can't make the user wait like that.

  I've looked into qt-faststart, and I was able to use it on my computer to modify the file so that it can start playing while it's being loaded. Unfortunately, this requires two steps. I first have to completely convert the file, then when it's done I have to use qt-faststart.exe on it. Again, this doesn't isn't really an on-the-fly solution. I'm sure there has to be some way to do produce similar results in a single command to be output to the player... right ?

  There is more video data on the server than I currently have space for on my hard drive, so to permanently re-encode each video, even in batches, would be troublesome, because I'd have to download some, convert, reupload, download more, etc. If I have to do that, I will, but I would prefer to leave them as is and be able to transcode on the fly.

  Any ideas ?

• Is there a way to calculate a average bitrate of video stream for each second ? Using ffmpeg or gsteamer toolkits [closed]

  15 mai 2012, par IOException

  I've encoded some video sample by different x264 presets. I already gathered some metric for each preset's file sample (PSNR,SSIM http://en.wikipedia.org/wiki/Structural_similarity)
  Now I am curious in instant (every seconds) file sample's bitrate, to compare them.

  I found out simple solution by googling around :

  http://akuvian.org/src/mplayer/avi_bitrate.pl
  This works on AVI files (regardless of codec), so you'd have to remux it first.
  Requires perl, mplayer, and gnuplot.

  I works for me

• Convert a video to audio on an android device (Java)

  25 mai 2012, par user1237578

  My problem is very basic, yet I find it incredibly hard to find a solution.

  I have made an android app which downloads videos from a server and is then supposed to convert them into mp3, because it's for music downloads. The problem now is that I can't really find a lightweight way of converting the videos.

  I have looked into a suitable ffmpeg library/wrapper already, but couldn't find a simple solution to use on the android. I'm already using ffmpeg on my windows machine, but it is console-based.

  All I need to do is convert mp4 into mp3 but somehow there doesn't seem to by any simple solution to find, also I'd rather not use an external web service because I can't rely on a website to always function, while my app should.

  I hope I've made myself clear, and thanks for taking the time to read this.