What size are HD video files on the iPhone 4?
Apple offers the iPhone 4 in two capacities, with 16GB or 32GB flash drives. Video recording quality has been vastly improved with the addition of full 720p resolution HD at 30 frames per second. This also means that more disk space is required to store video files.
12 minutes of HD video will take up approximately one (1) GB of space on your iPhone 4. This equates to approximately five (5) GB of file size for one hour of HD video recording.
The iPhone 4 also features a front-facing camera that records video at lower VGA quality.