I've managed to write a limited video player able to view a .3gp file from internet. The video will be shown centered full screen, maintaining the video aspect ratio. Also, rotations don't interrupt the video, which keeps playing without problems.
Everything seems fine, but... on my HTC Legend when you rotate back to portrait, the video is corrupted, and instead of showing full screen it is displayed at its native pixel size. But rotating again to landscape works and is shown perfectly. Any ideas why? Unfortunately I don't have more hardware to test this on and I've run out of ideas to test.
You can get the full example source code from https://github.com/gradha/Android-video-stream-rotation. Here are screen captures of me opening the application, rotating to landscape, touching the screen to display the video controls, then rotating back to portrait to see the corruption.