![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 | Firefox Support Forum | Mozilla Support 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 | Firefox Support Forum | Mozilla Support](https://assets-prod.sumo.prod.webservices.mozgcp.net/media/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 | Firefox Support Forum | Mozilla Support
Zed A. Shaw, Writer on Twitter: "Watch Firefox lie. See how it reports that the video cannot be played, but then whoAAAAA! Magic it plays just fine. Maybe it can't be *streamed*,
![Firefox won't play many videos, sounds and other Html5 applications but Youtube is fine. | Firefox Support Forum | Mozilla Support Firefox won't play many videos, sounds and other Html5 applications but Youtube is fine. | Firefox Support Forum | Mozilla Support](https://assets-prod.sumo.prod.webservices.mozgcp.net/media/uploads/images/2015-09-21-15-49-24-ed9117.png)
Firefox won't play many videos, sounds and other Html5 applications but Youtube is fine. | Firefox Support Forum | Mozilla Support
![Enable all video codecs on Firefox (MSE & h.264, Media Source Extensions, MSE & WebM VP9, h.264) - YouTube Enable all video codecs on Firefox (MSE & h.264, Media Source Extensions, MSE & WebM VP9, h.264) - YouTube](https://i.ytimg.com/vi/R4No4kv3TA8/maxresdefault.jpg)