When you hit the zoom key (which is a 2x screen size increase, therefore 2 x 2 = 4), you are quadrupling the number of bits per frame that the processor has to deal with. PocketMatrix doesnot encode the video to address this. If they did, they would have to, as a minimum, half the frame rate during the encode.There just isn't enough processing power within any of the StrongARM processor based PDA's to view an MPEG4 based video clip with a screen resolution of 320 x 240 at nothing more than 10 - 12 fps (with audio reduced to a single channel, etc.)
So unless you like to watch videos with a 10 to 12 fps frame rate, (somewhat jerky) most people encode with 20 - 24 fps for a smaller screen resolution and use the zoom feature to watch only specific segments of their movie.
