Amazon Kindle Fire is my current portable video player. Kindle Fire’s 1024×600 wide display is better to watch movie, music video than iPad 1024×768 display. No black bar on top and bottom of the screen. However, the default video player in Kindle Fire is not perfect to do the task. Therefore, I pick my favourite video player from Samsung Galaxy S II ~ MoboPlayer. MoboPlayer is working perfect on Kindle Fire. The 2 features that I like most ~ adjust volume and brightness with slide up and down.
There is still a small bar at the bottom while playing video with MoboPlayer on Amazon Kindle Fire stock software. Not actually full screen mode. But you can have full screen mode in CM7 ROM. Hardware decoding is depending on Kindle Fire codec support. Playback 1080p MP4 video is smooth. Other format which lack of hardware codec support like RMVB, MOV, MKV can only support up to 480p mode smoothly. Another video player that I like ~ DicePlayer failed to run on Kindle Fire at all. So MoboPlayer is the best free Android video player on Kindle Fire (at least for me).