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• Is there a difference between these two ffmpeg commands to extract an image from a video file ?

  22 septembre 2022, par Fractale

  I don't really understand the first one but it looks to be the popular option.

  


  The second one is the one I made on my own reading the man page but I'm not sure I do it right.

  


  ffmpeg -i inputfile.mkv -vf "select=eq(n\,0)" output_image.jpg
ffmpeg -i inputfile.mkv -frames:v 1 output_image.jpg



  


• PHP-FFMpeg prerequisites

  20 février 2014, par Jesse Adam

  
  I'm attempting to implement https://github.com/PHP-FFMpeg/PHP-FFMpeg

  I copied the src/FFMpeg folder to my includes folder and made sure my autoloader knows where to find everything.

  as a test I made a script that simply does :

  $ffmpeg = FFMpeg\FFMpeg::create();
  
  $video = $ffmpeg->open('video.mpg');

  I get :

  Fatal error: Class 'Doctrine\Common\Cache\ArrayCache' not found in /var/www/php/include/FFMpeg/FFProbe.php on line 203 

  My question is : does PHP-FFMPeg require Doctrine, because that is not stated in the documentation. What version do I need ? Are there other prerequisites ?

  I could create a new question for this, but I'm not sure if I should. I now have PHP-ffmpeg implemented. I'm using Laravel, however that should be irrelevant for this question. I'm trying to enable progress monitoring. It works, however I need to pass in an ID so I can update the correct key in memcache.

  $id = 12345;
  
  $format->on('progress', function ($audio, $format, $percentage) {
  
      //this works perfect, but doesn't tell me which item is being updated 
  
      Cache::put("progress", $percentage,  .25);
  
  
  
      //this does not work as I am unable to pass in $id, if I add it as the 4th argument above it will display the number of threads or something
  
      //Cache::put("{$id}_progress", $percentage,  .25);          
  
  });

  I need clarification on the "on" method. I looked through https://ffmpeg-php.readthedocs.org/en/latest/_static/API/ and was not able to figure out how this method works. Any help would be appreciated.

• Play video files online sequentially without delay/buffering between videos

  26 février 2015, par Marko

  Is it possible to play video online that’s made of two or more video files ?

  Since my original post wasn’t clear enough, here’s expanded explanation and question.

  My site is hosted on Linux/Apache/PHP server. I have video files in FLV/F4V format. I can also convert them to other available formats if necessary. All videos have same aspect ratio and other parameters.

  What I want is to build (or use if exist) online video player that plays video composed of multiple video files concatenated together in real-time, i.e. when user clicks to see a video.

  For example, visitor comes to my site and sees video titled "Welcome" available to play. When he/she clicks to play that video, I take video files "Opening.f4v", "Welcome.f4v" and "Ending.f4v" and join/merge/concatenate them one after another to create one continuous video on the fly.

  Resulting video looks like one video, with no visual clues, lags or even smallest observable delay between video parts. Basically what is done is some form of on-the-fly editing or pre-editing, and user sees the result. This resulting video is not saved on the server, it’s just composed and played that way real-time.

  Also, if possible, user shouldn’t be made to wait for this merging to be over before he/she sees resulting video, but to be able to get first part of the video playing immediately, while merging is done simultaneously.

  Is this possible with flash/actionscript, ffmpeg, html5 or some other online technology ? I don’t need explanation how it’s possible, just a nod that it’s possible and some links to further investigate.

  Also, if one option is to use flash, what are alternatives for making this work when site is visited from iphone/ipad ?