在JAVASCRIPT中运行FFMPEG命令

Question

I'm trying to extract some frames from a video with ffmpeg when the video file is selected (not submittet) so i can create a video thumbnail preview. All i could come up with was this php version, but i'd like the preview to be live, so it needs to be a javascript function. For a js noob, how do i make javascript do the same as this php?

  <input type="file" name="video" onchange="JSfunction-that-extracts-video-frames();"/>

  <?php 
         $ffmpeg = "/usr/local/bin/ffmpeg";
         $size = "320x180";
         $videoFile = $_FILES['file']['tmp_name'];

         for($num = 1; $num <= 15; $num++)
         {
           $interval = $num * 3;
           shell_exec("$ffmpeg -i $videoFile -an -ss $interval -s $size videos/$num.png");
         }
   ?>

Answer 1

I would recommend making PHP save the screenshot into a folder or Base64 it. Then once PHP has done it, use AJAX to display the screenshot the client. Loading the screenshot dynamically for the client via plain javascript wouldn't work properly.