MIME type for playing mp4 video in firefox

Forgive me mates but this is the only thread i find about mp4 video playback issue. i just have a very related and similar problem. May I post it here to look for an answer. Did you ever know the output format - FBR? because recently i used this video screen capture program that is BB Flashback, to record HD quality videos. However, the output video generated by this application was an FBR video file. I couldn't play it in windows media player or vlc. Later I found this article (http://www.videoconverterfactory.com/tip...o-mp4.html) and required that first of all, i must convert FBR file to mp4 format . What i want to know is whether converting video is the only available method to fix this playback issue because video compression always causes quality loss to some degree (the original video is 1080p 60 fps) and if there is an alternative method such as changing a file's .extension or trying another more compatible media player?