![Firefox 49 error Firefox 49 error](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2016-09-29-13-37-52-ec2966.png)
Firefox 49 error "This browser does not support video playback" playing mp4 videos in Twitter in Win 8.1 with Flash Player 23.0.0.162 | Forum pomocy dla programu Firefox | Pomoc Mozilli
![HLS/MP4/etc Video Playback (Unless of course, Microsoft Windows 10 Media Feature Pack was included) not working or playing or (re)loading (example: Twitter, or et cetera, or other) in Windows 10 Safe Mode : HLS/MP4/etc Video Playback (Unless of course, Microsoft Windows 10 Media Feature Pack was included) not working or playing or (re)loading (example: Twitter, or et cetera, or other) in Windows 10 Safe Mode :](https://preview.redd.it/fo9jc8samwc81.png?width=1920&format=png&auto=webp&s=89d392854d65904782cd93c679966ef8d0097354)
HLS/MP4/etc Video Playback (Unless of course, Microsoft Windows 10 Media Feature Pack was included) not working or playing or (re)loading (example: Twitter, or et cetera, or other) in Windows 10 Safe Mode :
![Firefox 35.0 launches with new Hello video chat and MP4 playback on Mac - Gear | siliconrepublic.com - Ireland's Technology News Service Firefox 35.0 launches with new Hello video chat and MP4 playback on Mac - Gear | siliconrepublic.com - Ireland's Technology News Service](https://www.siliconrepublic.com/wp-content/uploads/2014/12/201501/firefox-logo-718x523.jpg)