HTML5 video of type video/mp4 playing audio only

I have an app built with codeigniter and launched in Facebook. This app should allow users to upload videos of type mp4. The videos upload fine. I had set the mime type in mimes.php as `'mp4' => array('video/mp4', 'application/octet-stream')`. I uploaded a video that showed up as type application/octet-stream when I checked with codeigniters file upload class. But I uploaded another video with ext .mp4 and it was uploaded successfully. The video that plays fine shows up as type application/octet-stream when I echo the file type, but the video that only plays audio shows up as type video/mp4. However when I try to view the video in my interface, using HTML5 video, it plays, but only audio. You can hear the sound as the video plays but I can't see the video itself. How do i fix this? EDIT: The video that plays only sound can be seen here You can see the video if you view it on my machine in a video player, but it only plays audio on the web. The code that displays the video is ``` <video width="410" controls> <source src=" <?php echo base_url().$upload_path.'/'.$videos_dir.'/'. $item['name'];?>" type="video/mp4"> Your browser does not support the video tag. </video> ```