I've been scouring the web for video specs along the lines of the iOS Human Interface Guidelines for graphics and icons (https://developer.apple.com/library/ios/#documentation/UserExperience/Conceptual/MobileHIG/IconsImages/IconsImages.html#//apple_ref/doc/uid/TP40006556-CH14-SW1) but the most I can find is a mention in the section on "Media Layer" under "Video Technologies" (http://developer.apple.com/library/ios/#documentation/miscellaneous/conceptual/iphoneostechoverview/MediaLayer/MediaLayer.html).
Specifically:
The video technologies in iOS support the playback of movie files with the .mov, .mp4, .m4v, and .3gp filename extensions and using the following compression standards:
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, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats
H.264 video, up to 768 Kbps, 320 by 240 pixels, 30 frames per second, Baseline Profile up to Level 1.3 with AAC-LC audio up to 160 Kbps, 48 kHz, 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, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats
My question: are these the only options across all platforms? So an H.264 video at 640x480 and 30fps is going to have the same quality on an iPhone with retina or an iPad with non-retina or an iPad mini? Or should we use, say, a 640x1136 video for iPhone 5, a 320x480 video for iPhone 4 (non-retina), and a 2048x1536 video for iPad with retina?
