Started using Firefox about a month ago. I have a Synology diskstation that runs their Photostation 6 software. It essentially uploads all the photos and video from your Iphone automatically and puts them on the diskstation and they can be looked at via a webbrowser. The files are in the original Apple format: video is .mov in the mp4 container. I can view the videos using Chrome. I can view them using IE. I can view them in Windows 7 natively. When using Firefox (38.01) I get the following error: "Error loading media. File could not be played" using the debug console - it looks like the player being used is JW Player 6.5.3609 Premium. When right clicking in Chrome or IE - the same player is being used without any problems. I updated all the plug ins, all of Apple's are there. Bottom line - the PC plays the files, two other browsers play them on the same computer, Firefox is the only one that doesn't. My laptop running Firefox on Windows 8.1 also doesn't play the videos through Firefox. Chrome and IE on the laptop work.