The Samsung Galaxy 10.1" tablets currently don't have an AC3 audio codec. This means that you are pretty much out of luck for watching most xvid videos without doing a little extra work. The best solution that I have found is to convert only the audio to aac (mp4) and reassemble your video into an mkv video file. It takes a bit of time, but because you are only re encoding the audio, it takes a fraction of the time of other methods. Assuming you have a Windows PC, go to the vid2eva support forums and download "VID2EVA-2010-12-14.zip." It is all you will need. You will find a PDF inside which detail the steps needed to install it. Once installed as per the instructions, you run the config application (advanced options) and change the outbound audio to MP4. After this is done, all you have to do is right click the video file and tell it to convert the audio. If you plan on playing the videos from your PC, I registered and have been using Little Player which has a server (PC) element and seem to work pretty well, having smooth play back in hardware mode. There are plenty of different ways to play video - I am just sharing what works for me.