How many HD video minutes do I get per 1GB of free storage?

The iPhone 4S takes video at 1080p and 30 fps and initial tests are showing that video takes 200MB per minute. At roughly 12 GB per hour, what seemed staggering a year ago is now quite quaint with the iPhone 4 recording at less than 5 GB / hour.

MacWorld reports that an hour of iPhone 4 video is 4.8 gig.

The iPhone records its 720p HD video at around 10 megabits (Mbps) per second. That translates to about 80MB per minute, as we noted above, or a staggering 4.8GB per hour. (Hope you sprung for the 32GB model!)

I just made a 15.5 minute test video with my iPhone 5S. File size is 1.31 GB, or 85 MB/minute. 7 GB of storage would handle 82 minutes of video.

Of course the complexity of the video and audio should have an effect on the compression, so this is just a rough guideline.