Here's a link to a datasheet of a "video rate JPEG compression chip". The chip processes one VGA sized frame in about 20 ms. That are 50 frames per second (1 / 0.020) ! It can process a 1280 x 1024 pixel image in about 80 ms (=12 fps). I did the math for a 1280 x 720 pixel frame as explained on page 3 of the datasheet and calculated 17 fps. Mind you this data sheet is from ten years ago. When 17 fps, 720p video was possible ten years ago what's possible today? On the other hand many of the 2007 cameras have a 30 fps, 640 x 480 movie mode and a 15 fps, 1280 x 720 movie mode. Do manufacturers still use 10 year old solutions? It seems so.
