Meeting the high resolution challenge

(Also posted on Pacific Fibre’s blog)
The iPhone retina display is awesome – not quite perfect, but incredibly high resolution that you can look at for a long time.

It has 326 pixels per inch, and 0.614 total megapixels. That’s not a lot of megapixels when we compare to the latest cameras with well over 10 megapixels.

But what if we scale the retina display up? If we make a 14.2 inch diagonal (12.6*6.6 inch) screen, then the number of megapixels becomes 8.8. What’s more important about that particular size is that it’s one of the standards for 4k video – 2160×4096.

The screen I’m typing on is Apple’s latest – 27 inches, 2560×1440 pixels and 3.68 megapixels. It’s a pretty high pixel density screen, but it pales besides the retina resolution.

If we make a 27 inch retina resolution display then we’d need about 4320 x 7680 pixels, to give 33.2 megapixels. This happens to be the specification for Ultra High Definition TV (UHDTV) which is still in its early stages, but the Wiki page says that target dates are 2016 to 2020. HDTV resolution is more than current consumer digital cameras can handle, and more than the latest MacBook Pro’s video card can handle as well – it’s limited to 2560 by 1600 pixels. So for this to work we’ll need new computers, new screens and new TVs – and none of these will be cheap at first. But we’ll all want them.

The fun begins when we start estimating how much bandwidth delivering full screen video will require at these resolutions.

The uncompressed UHDTV streams are 24 Gbits/sec, or 2400Mbits/sec – which is about 800 times more capacity than the average premise in Australasia and a significant percentage of New Zealand’s current total purchased international capacity.

Compressing the streams helps a lot – apparently the video (sound is extra) can go to 180-600 Mbps, which is still well out of out league for premises in Australasia.

The 4K (or 14 inch retina display’s full screen video) stream would be about 6.6 Gigibits/sec uncompressed, and 48-160 Mbits/sec compressed using the same compression ratio. That’s still way out of New Zealand or Australia’s reasonable ballpark speed to the premise.

Even the iPhone 4’s retina display would need 444Mbits/sec to drive uncompressed full screen video, and 3-11 mbps per second compressed. Our 3G networks and fixed networks are capable of delivering those compressed speeds, though the averages are quite a bit lower. This meshes in with real-world experience – sometimes video works well, other times it does not.

It seems that UHDTV, arriving hopefully in 2016-2020, will be delivered via the Internet. That means we’ll need 100Mbit or 1Gbit fibre to our homes to receive the service – and we are actually on track for that with the UFB and NBN initiatives. It doesn’t seem too remote that SkyTV or other operators can serve broadcast TV over fibre at theses speeds, but there is certainly plenty of end to end work to do to get there. I’d far rather have ultra-high resolution TV than the silly 3D TV that manufacturers are trying to push at the moment.

But what if the YouTube and Skype standard resolutions increase from the current HD to UHD? All of a sudden we will each be able to stream individual videos at say 250 Mbits/sec.  If more 50,000 devices (that’s about 1 in 20 premises in New Zealand, though each premise has multiple devices) did this at once, at say 250 Mbits/sec on average, then we’d need 12.5 Terabits/sec of data being streamed – and much of this would be from offshore.

That’s a huge number – the entire Pacific Fibre cable, servicing Australia and New Zealand, is planned to be about 5.12 Terabits/sec at launch, while the entire unlit market capacity right now is not much more than that.

So clearly there is enough demand for a new cable system.

About Lance Wiggs

@lancewiggs
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7 Responses to Meeting the high resolution challenge

  1. Amnon says:

    It’s easy to mix up, but worth being clear on resolution versus pixel density.

    The iPhone retina display is awesome – not quite perfect, but incredibly high resolution that you can look at for a long time.

    The Retina display has a very high pixel density, but its resolution is quite low, as you say, at 960×640.

    The screen I’m typing on is Apple’s latest – 27 inches, 2560×1440 pixels and 3.68 megapixels. It’s a pretty high pixel density screen, but it pales besides the retina resolution.

    The 27″ display has a higher resolution, but a lower pixel density when compared with the Retina display. :)

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    • Amnon says:

      Whoops, it stripped out my quote tags. The 2nd and 4th paragraphs are quotes from your posts; the 3rd and 5th are my replies. :)

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      • Lance Wiggs says:

        fixed thanks. And yes – you are right the sentence should read:
        The screen I’m typing on is Apple’s latest – 27 inches, 2560×1440 pixels and 3.68 megapixels. It’s a pretty high pixel density screen, but it pales besides the retina screen’s pixel density

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  2. Craig says:

    This is a great post. When I hear people say that Australia has no need for the NBN and can just use wireless or 4g they obviously have no clue about the potential for high quality video streaming the NBN will deliver that wireless never can. Fiber is needed for the future. Wireless is for the boring and unimaginative.

    Like

  3. Adam says:

    With devices like a phone, you generally are closer to them than a computer screen or a TV, so the same pixel density on a computer screen as an iPhone would just be a waste. Your eyes would not be able to appreciate the additional pixels past a certain point.

    The same goes with TV. There have been studies done, and from memory, most people can’t tell the difference between a 720P picture and a 1080P picture on a 50″ screen at normal viewing distance, so going to something like 4K is really just a waste of pixels.

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    • Lance Wiggs says:

      Do you have a citation for those studies Adam?

      I for one will line up for SHDTV. First to replace the normal HDTV which isn’t perfect by any means, second to allow for even bigger screens and third to allow for super tablet experiences and minority report-type experiences.. L

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  4. It’s a great post. When I hear people say that Australia does not need the NBN and simply use 4G wireless obviously have no idea about the potential for transmission of high quality video wirelessly deliver NBN than ever. Fiber is necessary for the future. Wi-fi for the boring and unimaginative.

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