Sunday, 30 May 2010

The iPhone 4 screen - a multimedia flop?

    We all know that iPhone started out with that is know as the lowest resolution ever used on a modern touch screen phone - 480x320px and a non-standard 3:2 aspect ratio. Why apple chose this format  is not sure but it's certain that most Chinese gadgets and knock-offs use non standard screens and they are cheaper to get than the standard ones; we should also keep in mind that the success of the first iPhone was somewhat mediocre when compared to it's non-touch counterparts like N95 and later models.
     What does that mean for the end-user? First of all it means that watching shows on either iPhone or iPad will give you two nasty horizontal thick black stripes that will pointlessly draw power while not displaying anything and that the faulty aspect ratio leads to loss of screen estate. Second, the abysmal resolution in the first iPhone made it very hard to distinguish page elements without zooming in as most web-pages retain a compatibility width of 640px. Another fun thing would be for the fourth iPhone to be called HD as it's aspect ratio resembles more to TV's from the 80's than to anything we consider HD today.

     By now you must be thinking how about the screen size? Could Apple really switch to a standard resolution like 800x480 since there's plenty of devices out there using a 3.5" screen? The short answer is no. The long answer is that the iPhoneOS does not use a scalable UI and not having a scalable UI means either the iPhone UI will either have black bars like movies currently do or the UI elements will be stretched and deformed while the applications that aren't re-coded will suffer the same faith as the UI.
    So what did apple do to overcome this huge drawback? Well so far they have done nothing as the average iPhone user doesn't even know what resolution means. But now with the fourth device of the series, that has a surprising resemblance with Nokia's internet tablet N800, Apple seems to have decided to give iPhone an internet tablet worthy resolution that other OSes (Symbian and Android) have had for years.

     A new resolution, a new hope, right? Almost, but not quite. What Apple actually did was double the resolution: 480x320px to 960x640px while keeping the screen size. As a consequence one pixel was "split" in four, meaning that the power draw from the screen may have doubled (considering that the screen is responsible for 60% of the power consumption of the device under normal usage, yet another wave of complaints is to be expected regarding battery lifetime). 
    Right now you might think that this might actually work wonders on the display quality... unfortunately not. Even the best eyesight won't be able to tell if a screen has 900 pixels or 700 pixels in width. The human eye can see, under normal circumstances, approximately 200ppi (pixels per inch). Everything below that is bound to be disturbing. Everything above, requires you to stare for at least 60 seconds, time required by your eye's lens to accommodate, to a picture of 200ppi next to one of 250ppi, if you hope to see quality and detail differences.
    Although an upgrade was necessary the jump from  the mediocre 160ppi Apple has provided so far (see iPad for sub-mediocre 132!!!) to 320ppi is a waste of pixels and battery life.
    Further more existing applications and especially 3D games will not take any advantage of the new resolution and will continue to run on a 480x320px resolution. New games however will not only draw 4 times as much power due to the screen resolution but also due to the graphics chip that will have to deliver 4 times the computing power. Considering the stress on the CPU though, it is less likely even for new 3D games to benefit from the new resolution; either that or the quality and details will be decreased for the sake of the new resolution.

    The way apps behave on the iPad is a clear example of what you can expect them  to behave on iPhone 4S; however if they looked good at first on the first iPhones, they shouldn't look worse on the 4S as the display size and aspect ratio are kept (3.5"). As a reminder of what a faulty aspect ratio means, you can check Apple's own fake advertisement (made on the back of a "cut" Star Trek) and see what the DVD version of the movie actually looks like.

     John Gruber of Daring Fireball has an interesting story about the absence of certain iPhone apps — Stocks, Calculator, Clock, Weather, Voice Memos — on the iPad.
It seems that these apps, when scaled up to iPad’s bigger screen, simply didn’t look good enough to Steve Jobs, so he decided to scrap them. Gruber writes:
“Ends up that just blowing up iPhone apps to fill the iPad screen looks and feels weird, even if you use higher-resolution graphics so that nothing looks pixelated. So they were scrapped by you-know-who. Perhaps they’ll appear on the iPad in some re-imagined form this summer with OS 4.0, but when the iPad ships next month, there won’t be versions of these apps.”
  The iPhone users are the only users not to have experienced an AMOLED screen from their favorite brand yet. Keep in mind that the so called "Retina" display is nothing more then your average old TFT technology, that has the single advantage of having more ppi than usual TFT displays. TFT's main disadvantages are that it can't generate it's own light, always needing a backlit panel and because of that panel the "light leakage" phenomenon appears. On the other hand, without needing to be backlit, AMOLED is thinner, up to 30% more economical and provides much higher contrast rates as pixels will be turned off in black areas of a picture or movie whereas TFT has to struggle with the always-on backlight (see pic). AMOLED also provides an even lighting of the entire screen surface compared to TFT screens where you can always clearly see brighter and darker areas - "light leakage" (try it on a full white and full black picture in full-screen). 

Regarding sunlight, the TFT has the advantage of the backlit panel which can be pushed much further than readability actually requires it, so it is expected that Apple will take advantage of that in the first firmwares to back Steve Jobs's claims up, and then probably bring it down to normal levels in the 3rd firmware release or so, to conserve battery life. However TFT displays also have the disadvantage of the light having to go through the display pixel layer and light it, thus requiring much more power than an AMOLED to reach the same brightness. This also affects the viewing angles in the worst possible way (see first picture), but we expect better results than on the 3GS since the pixel size is reduced in iPhone 4; AMOLED is yet again the winner since it has no limits on the viewing angles! We don't want to suppose anything yet but the comparison AMOLED you see above belongs to the Samsung S8500 that has full-usage battery life of over three days! The best solution would have still been for Apple to use more up-to date technology.

Dead pixels
      Another issue the iPhones are currently facing are the dead pixels. Although it's something you might not expect this from a device with a resolution as small as 480x320px, the iPhone is still manufactured at Foxconn in China, the place where most mobile vendors assemble nothing more than their chargers. This might occur either due to mishandling or because of the lo-cost, no-name, no-brand TFT matrixes themselves.
     There are almost two million results on "iPhone dead pixel" in Google, a few thousand complaints on various Apple forums, and various sites with tips&tricks on how to fix your stuck/dead pixels on iPhone. 
     What is worriable is the circuit and sub-pixel complexity required for 320ppi - if there's thousands of complaints for 160ppi on 3GS, what's it gonna be for the new iPhone?

    Last but not least are the issues with the capacitative screens. Among those issues the one above is the worst. You probably know that iPhone's touch screen doesn't work with anything else but your finger. As much as this might sound like a minor inconvenient, the fact that the screen uses your electrons is the actual cause for dead pixels. By now you probably zapped yourself once or twice and know what static charge is. Well the picture above is exactly the result of what happens when static meets iPhone - dead pixels! 
   The other aspect is how much apple insisted on the capacitative screens being scratch proof. Well how scratch proof is that? The screen cracks easier than an eggshell on the slightest pressure or drop. And what good is a scratch-proof screen when the rest of the devices scratches worse than ice? I wont even mention the cracks anymore. For once I'd like to see a resistive screen on an iPhone, better scratched than cracked, this blogger says especially both the scratching and the lack of sensitivity have been greatly exaggerated.

Strong points:
  • The unusual resolution on iPhones makes them the worst possible candidate to enjoy multimedia and videos mostly because of the black bars (but also because of the lack of codecs: DivX, XviD, etc).
  • The aspect ratio on the iPhone is closer to old 4:3 television sets rather than anything HD.
  • The increase in pixels per inch is useless, as it cant be noticed by the naked eye, takes a microscope to see and great toll on the battery.
  • TFT technology depends on a backlit panel thus providing lower contrast, lower view angles and higher power requirements.
  • Considering the human eye limit, you won't be able to sense a difference in sharpness from 960x640px to 640x360px on a 3.5" screen - but again, your battery will.
      • Using a standard resolution on the iPhone would require for most of the software to be rewritten as the iPhone UI is not scalable.
      • The increased resolution should make browsing more pleasant but you'll have to zoom in if you want to be able to actually read the text.
      • Capacitive screens are prone to crack and develop dead pixels if not properly insulated/grounded.