What are the optimal settings for a video that will be played on a Galaxy Tab 10.1? What are the best size, compression settings, and format for making video for playback on a Galaxy Tab 10.1?
Video

The Galaxy Tab 10.1 will work best with MP4 files (H.264 encoding) at 720p (1280x720). Do not use Entropy Coding. I'm noticing a few problems with it; it could be the video / my setup though and not the device itself.

Use a constant bitrate at a reasonable quality level (RF:20 should be good, or around 1000kbps). Maximum B-Frames should be set to 0, and Reference frames to 4 or 5.

Audio

As far as audio goes you should be fine with most anything; a samplerate of 48 and a bitrate of 160 should be good. Make sure to downmix to stereo. AAC is probably you best bet for the codec.

Summary

More information can be found here and here (though you might want to experiment a bit with some of the advanced settings if you feel that you need them—Probably not a big deal though).

Audio: AAC with Bitrate of 160, Samplerate of 48; downmix to stereo
Video: H.264 in an MP4 wrapper at 720p (1280x720) at a constant bit rate