iPhone 4S 1080p Gb/Hour requirements?

[bniu]

I agree the jump from 480p to 720p is more dramatic than 720p to 1080p, but that's not a good reason not to move forward with technology. 1080p is still noticeably better than 720p if you have a good enough screen to watch it on.

only problem is my big screen tv at home is a six year old 720p screen and I've been dragging my feet on replacing it until 3D big screens get cheaper...

 

[AdrianK]

No way. That's about what the iPhone 4 720p does. I might be wrong with my guess, but this is way under.

Apple bumped the H264 profile to main - it was baseline for the 4 - probably because they have more horsepower available for encoding with the A5. This means that can get a better picture at the same bitrate.

Picture quality at a given resolution isn't just about bitrate, the types of frames used in the encode (as determined by the profile) are very important as well. Encodes with the same bitrate and resolution look a lot different with Main and Baseline.

Just realized you said my way was more complex, but the better way takes more steps.

We both found the bitrate using a constant for quality, but yours took more steps, surely a more a efficient method is a better method? That's not the problem though, the constant you used for quality was what you guessed for the iPhone 4, not the real value.

For predicting the bitrate apple would go for, it would make sense to assume that resolution:bitrate (for the same profile) would be 1:1. To work that out I used the bitrate from the iPhone 4 at 720p.

You didn't. You essentially performed the same calculation using your guessed 720p bitrate from last time. Which wasn't correct.

This turned out to be very close to actual video. My estimate for iPhone 4 720p HD video was 79MB a minute and real videos came out to about 83MB.

About 1 MB of this difference could be the audio recording

64kilobits/s * 60 seconds = 3840kilobits or 0.47megabytes.

Your 3.53megabyte difference (being 4.5% off the real value, according to your figures) was why we got different results for the same calculation. That's the bottom line, I used an exact value, you didn't.

This little amount could easily vary depending on what you are recording and how well the compression can work.

But that's not how it works. The iPhone aims to achieve the same target bitrate each time. If it starts dropping frames then each frame will just get more bits to utilise.

 

[HobeSoundDarryl]

only problem is my big screen tv at home is a six year old 720p screen and I've been dragging my feet on replacing it until 3D big screens get cheaper...

But even there, scaling down from 1080p to your current 720p screen is going to yield an excellent 720p picture for now and until you "stop dragging your feet." And if you shoot some good stuff in 1080p until you can get that new HDTV, it will probably be 1080p and all that video will look great... much better than upscaling from 720p to 1080p on your next set.

Big storage is cheap. Capture it at 1080p, render it at 720p for now and be ready for later. You won't be able to come back to now to re-shoot stuff in 1080p when your next television is in place.

I recall owning CDs and DVDs before I even owned players. Building up some footage before you can fully utilize it is just getting ready for when you can fully enjoy it.

 

[dizzy13]

Adrian, you talk a good game and it all sounds very technical, but you were wrong and I was right. Period.

 

[AdrianK]

No matter how close, your guess is irrelevant because the method you used to generate it is flawed, as I've explained quite clearly. So really you just generated a meaningless number.

 

[dizzy13]

LOL, Ok buddy.

I'd rather be flawed and smarter and correct. Than act like I'm the smartest kid in the room and then proven wrong.

 

[julesw]

not enough

I just shot a video today on my 4s, 16gb

24 mins of 1080p and it was full, and i don't have much else on the phone..
should have got a bigger memory

 

[nateo200]

iPhone 4S has gyro stabilization.

That means next to nothing to someone with shaky hands.

720p good enough for you? Great. Better hardware can usually easily handle lesser standards. If this camera can shoot 1920 x 1080 video it can probably easily handle (and continue to shoot) 1280 x 720 too. My 1080p camcorder has options for shooting at various resolutions, various bit rates, etc. Maybe this "camcorder" feature will too.

No, 4k is good enough for me. My point is 1080p is great but you shouldn't be a resolution whore. I shoot video in the maximum possible resolution and then downsample to 720p for proper looks. Do you really think 90% of consumers will need 1080p? I just think 60fps is a way better trade off if its not already possible...I can handle my HD DSLR handheld fine but with an iPhone things will get shaky regardless of what magical gyro technology Apple puts in. 60fps can really counter allot of shake...I use it allot for casual videos and it gives a traditional video look.