What is the correct dimentions for fullscreen video format on the iPhone

Question

I wan't to play video in fullscreen mode on the iPhone, but when I try to figure out how to transcode my videos I get confused about the video format specification from Apple on http://www.apple.com/iphone/specs.html

Video formats supported: H.264 video, up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second, Low-Complexity version of the H.264 Baseline Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; H.264 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Baseline Profile up to Level 3.0 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats

Why is the recommended dimention 640 by 480 pixels when the fullscreen is 480 by 320? (it doesn't even add up in ratio)

And if the ratio is correct why is it so? (Different pixel ratios?)

Answer 1

For pixel-exact video display on the iPhone, you'll want to use 480 x 320 H.264 with the settings they describe. I have an example video here that plays at fullscreen on the iPhone.

Videos with supported sizes that they describe will play, but will be scaled to the screen. You'll see black bars on the sides of the screen, unless you double-tap to zoom in on the video.