With the improved camera and video on iPhone 3G S, should you go 32GB?

by Justin Horn on Jun 10th, 2009 @ 7:50 pm

UPDATE Check out the updated version for the iPhone 4S

UPDATE Check out the updated version comparing the 3GS to the iPhone 4

Ultimiately the choice between the 16GB and 32GB iPhone 3G S is one you will have to make for yourself (or have already made with your pre-order) becuase I don’t know how many pictures, videos, or songs you want on your phone. My goal with this post is to provide you with all the facts to make this decision a bit easier.

Math Warning
If you don’t like math you may want to skip to the conclusion at the bottom of the post!

Pictures
The current iPhone at 2.0MP has an average files size of about 800 KB (0.78MB). The move to 3.0MP should make the average size about 1.3MB. So assuming you have 500 pictures on your iPhone the difference between the 3G and 3G S would be about 260MB, not that big of a deal. It isn’t till you get up to about 2000 3G S pictures that you start to feel the difference, eating an extra gigabyte of space over the 3G.

Video
Since the 3G doesn’t officially support video we can’t make a comparison, but let’s review the details to see how much space you’ll need for all those spontaneous videos. Video recording on the iPhone 3G S will be VGA 640 x 480 at 30 frames per second. The bit depth on the current iPhone 3G is 24, so let’s just assume is the same in the 3G S for the calculations below.

We’ll start out by letting Adobe do some of the math for us:

To calculate the size in kilobytes (K) of one frame of uncompressed video, use the following formula:

Frame size K = ( [Pixel Width x Pixel Height x Bit Depth] / 8 ) / 1024

Where 8 represents an 8-bit byte, and 1024 equals the number of bytes per kilobytes. For example, the size in kilobytes of an uncompressed frame of full-size (640 x 480), 24-bit video is:

Frame size K = ( [640 x 480 x 24] / 8 ) / 1024 = 900K

To determine the file size of one second of uncompressed video, multiply the image size by the number of frames per second (fps). For example, one second of uncompressed, full-size, full-speed (30 fps), 24-bit video is:

900K x 30 = 27 MB

To determine how compression affects file size, divide the file size by the compression ratio. For example, a 10:1 compression ratio will make a 27 MB file 2.7 MB.

Note: Although I have spent a good amount of time researching the H.264 compression ratio and feel pretty confident with the result I did have troubling finding an exact number. So with that in mind and the fact that we don’t know exactly how Apple will implement the video and compression your results may vary.

Based on my research I found the compression ratio of standard MPEG-4 is about 30-40:1 and the newer H.264 (or MPEG-4 AVC) which the iPhone uses is about 1.5 – 2x better. For my cacluations below I will use a H.264 compression ratio of 60:1, just about in the middle of what I found. So adjusting the above results for our 60:1 compression ratio let’s find how much space is needed per second. Then using that result we’ll figure out how much space we would need for a video fanatic that has 500 minutes of video:

27 MB/s  /  60 = 0.45 MB/s

500 min * 60 s / min = 30,000 s

30,000 s * 0.45 MB/s = 13,500 MB or 13.18 GB

So with about 500 minutes of video you will need about 13GB of space! I guess 500 seems like a lot, but right now I have about 400 pictures on my 3G. I could definatley see myself having between 100 and 200 2 to 3 minute videos so it’s not that far fetched! Although, with the ability to upload directly to YouTube you could dump your videos on there (expect for those “special” videos) and delete them off the phone to save space. With the built in support for YouTube you would still be able to show off your videos right on your iPhone 3G S without issue.

Conclusion
The jump to the 3.0MP camera won’t affect your space enough for you to warrant an upgrade to 32GB if you are currently happy with your 8GB or 16GB iPhone, but if you are planning on keeping a lot of videos on your iPhone 3G S I would definitely recommend going with the 32GB model. If you can live with uploading your videos to YouTube or moving them to your computer then you might be good with the 16GB.

Follow me on Twitter @justin_horn



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Apples & Oranges, iPhone

Comments

    1.
  1. [...] I’ve got it "kinda" figured out and wrote up a big long post on my blog about it here: With the improved camera and video on iPhone 3G S, should you go 32GB? | When Will Apple? I basically boiled it down to 0.45 MB/s. This number could vary though depending the compression [...]

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  3. [...] took a small video and came out to 0.48MB/s just a bit more than my 0.45MB/s estimate. tweetmeme_url = [...]

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  5. [...] year ago today, I created a post to help those getting ready to buy the iPhone 3GS decide if going 32GB was wroth the extra $100. Today I’m going to ask the same question of the upcoming iPhone 4 using the same template as [...]

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  7. [...] Jablickar.cz (via AppleInsider) were sent some pictures and videos taken with an iPhone 4 from a Czech user testing it. So I immediately went to check my numbers from my post, “With iPhone 4’s improved camera and HD video, should I go 32GB?” [...]

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