Playing video on an Android device can sometimes be a bit of a chore. The platform's native media framework has very limited support for mainstream formats and can really only play H.264 video that is in an MP4 or 3GP container. If you are using an mkv container or your video is encoded with wmv or xvid, it isn't going to play unless you reencode it or use a third-party video player that doesn't rely on Android's media framework.

After testing a number of third-party players, I finally found one called RockPlayer that performs relatively well and handles a broad enough selection of formats to satisfy my needs. Created by Chinese mobile software vendor Redirect Intelligence, it uses the excellent open source FFmpeg library to handle video decoding.

The free version of the program is fully-functional, but ad-supported. The advertisements will only show up when the playback controls are active. This means that you will sometimes see ads at the bottom of the screen when you are seeking, for example, but not while you are simply watching a video. It will also display a little red RockPlayer logo in the top left-hand corner at all times, including during regular playback. Users can remove the ads and the persistent logo if they pay $9.99 to upgrade to the full version.

When you launch RockPlayer, the program will show you a simple file manager interface that you can use to navigate to the video files that you have stored on your device's SD card. When you select a video in the built-in file manager, it will start playing.

You can tap the screen to toggle the visibility of the playback controls, which include a play/pause button, a seek slider, fast-forward and rewind buttons, a button that will optionally stretch the video to fill the screen, and a button to display information about the file that is currently playing. When the controls are visible, the current time and the percentage of remaining battery life will show up in the top right-hand corner.

RockPlayer is simple and predictable. It will handle pretty much anything that is supported by FFmpeg and it offers reasonable playback performance on standard-definition content, without the stuttering that I have experienced in some of the alternatives. It didn't fare particularly well with a 1080p clip, however. The $9.99 asking price for full activation is a little bit too much, but I'm pretty satisfied to use the free version with the logo. One free alternative that looks promising is arcMedia, but it's not quite as mature yet. For now, I think that RockPlayer is best choice for xvid and mkv support.