25
Jul
eyeball

Super ultra mega HD resolution support is coming to a robot-themed OS near you, but before we get into that, let's talk about Android and DPI.

screens-ranges

Android devices come in tons of different resolutions, everything from a tiny 128x128 watch screen to the massive 2560x1600 resolution of the Nexus 10. Higher resolution screens need higher resolution apps with higher resolution image files. It doesn't make sense to serve up super-high resolution assets to low resolutions screens, so to make sure the right screens get the right size files, Android has several generalized DPI categories for image assets. Each of these categories matches up with a range of hardware screen DPIs:

  • Low DPI (LDPI) = 120DPI
  • Medium DPI (MDPI) = 160DPI (The T-Mobile G1)
  • High DPI (HDPI) = 240DPI (The Nexus S)
  • Extra High DPI (XHDPI) = 320DPI (The Galaxy Nexus/N4)
  • Extra Extra High DPI (XXHDPI) = 480DPI (the HTC One)

Apps contain folders for each of these densities, and there are usually a full set of app images in each folder. The low resolution devices get the low resolution images, the high res devices get the high res images. It's all about efficiently using memory by serving up only the correctly sized image assets for each resolution.

So, if you haven't guessed by reading the title yet, Google has added a new DPI category to Android: XXXHDPI. This is for screens with an approximate DPI of six hundred and forty. Did you think we were stopping at 1080p? Hahahaha.

In the Android source commit, Android engineer Dianne Hackborn tries to inject some sanity into the situation by saying:

Standard quantized DPI for extra-extra-extra-high-density screens. Applications should not generally worry about this density; relying on XHIGH graphics being scaled up to it should be sufficient for almost all cases.  A typical use of this density would be 4K television screens -- 3840x2160, which is 2x a traditional HD 1920x1080 screen which runs at DENSITY_XHIGH.

Televisions. The Android team intends this for 4k televisions. Android supports 4K TVs! Great.

You know who is going to listen to that? No one.

The HTC One's 468DPI was starting to push the limits of what an Android app could support. Now though, the marketing-driven design teams are free to pointlessly inflate phone DPIs to over 600 DPI. You know they are hard at work on that right now.

Heck, printers today claim to be able to print in the multi-thousand DPI range; if the print guys see no reason to stop, why do you think the display guys will?

So, prepare yourselves people. While you might not see any benefit from the increased resolution, this will make the marketing department very, very happy.

Ron Amadeo
Ron loves everything related to technology, design, and Google. He always wants to talk about "the big picture" and what's next for Android, and he's not afraid to get knee-deep in an APK for some details. Expect a good eye for detail, lots of research, and some lamenting about how something isn't designed well enough.
  • http://www.androidpolice.com/author/ron-amadeo/ Ron Amadeo
    • http://www.androidpolice.com/author/ron-amadeo/ Ron Amadeo

      stupid broken disqus. =/

      • Dominic Powell

        Why don't you migrate to g+ fancy comment stream =p

        • http://www.androidpolice.com/ Artem Russakovskii

          It's by far not ready or officially supported.

          • TheWhiteLotus

            Why not?

          • http://www.androidpolice.com/ Artem Russakovskii

            It just isn't.

            It's only supported for Blogger. Every other implementation is a hack.
            It doesn't support any kind of comment sync for older comments.

            There is no comment export if we ever decide to leave it. In fact, I don't know how it could even work.

            There is no proper moderation, such as banning IPs or users (in fact, we don't even get access to IPs or emails). Sure, I can block someone, but they will be able to continue posting.

            But the main reason is I actually don't like the idea of having re-shares and stuff other than comments. That's way too much irrelevant crap. And even worse, all these re-shares have their own conversations going without even realizing they're collected and shown in one place. So get ready for completely unrelated or duplicate comments to show up everywhere because people who are commenting directly on G+ have no idea others are commenting in other threads and are being displayed next to them.

            I get that G+ integration is great, in theory, but it's not there yet, not even close.

          • QPR

            If you ever do that, please dont make it mandatory to have a Google+ account to post. I hate social media.

      • Dave

        Yes i also hate this Disqus ... please go to something better!

        • http://www.androidpolice.com/ Artem Russakovskii

          There's nothing better right now.

          • Dominic Powell

            If only we could make reddit comment threads, there would be peace in the universe

          • Jordan DeBarth

            For what its worth, /r/Android is pretty much an Android Police circlejerk, so you can always go there.

          • Floss

            It's amazing how Engadget moving off of Disqus made everyone suddenly very grateful for it.

          • didibus

            I left Engadget, slightly because the articles turned to crap, but mostly because they dropped Disqus. LyveFire just sucks, you can't even be notified that someone has replied to you.

            Dysqus has it's issues, some occasional bugs, and lack some backend features I'd like, but it's definitely the best comment platform I've seen to date, for blogs.

          • John

            I hate LiveFyre.

  • Valentin Cuellar

    maybe ultra instead of extra-extra-extra xxxhdpi or uhdpi which is better?

    • http://www.androidpolice.com/author/ron-amadeo/ Ron Amadeo

      yeah, that would have been much better.

      • TY

        What should we call after that? XXXXHDPI? XUHDPI?

        • Zhuowei

          DPI MAXX Ultra HD 4G LTE BBQ X

        • Adrian Zugaj

          Yes.

        • Zhuowei

          DPI MAXX Ultra HD Evo 4G One X

    • Dan

      I think 'extra-extra-extra' does a better job of highlighting the absurdity of the whole thing....

  • BrianLipp

    its really just the dpi you use for porn (xxx)

  • mechapathy

    The sexiest of all DPIs.

    • http://www.androidpolice.com/ Artem Russakovskii

      I see what you did there.

  • andy_o

    Printers' DPI is different than this "DPI". This one refers to pixels per inch. There's some confusion in digital photography about this as well, that's why most people now use PPI. The printer's "dots" are actual dots of ink of one color of the inks, while the pixels are a combination of RGB and can be any number of colors up to what the bit depth allows. When you're printing, you also take into account the PPI of the original picture (in number of pixels) with the target physical size of the print, and that has similar rules to screen "DPI", meaning a rule of thumb is 300PPI for a photo you'd hold as close as a phone. The printer's own DPI is separate from that, and one that does a thousand DPI may not even be able to resolve a print at 300PPI properly.

    • cy_n_ic
    • MeCampbell30

      Right, to elaborate, a printer uses 4 color dots to get the right blending effect. The more DPI a printer has the more sharp an image it can produce because the dots are smaller and the edges can be more defined. Pixels don't have this problem because they are square colors with fixed size and colors from one pixel don't bleed over to another.

      If I want to draw the thinnest line possible on a display I'm limited to the size of a pixel. If I want to draw the thinnest line on paper that I can I'm limited by the size of however many dots it takes to make a clearly defined line (which may be 5 or 10 depending on the ink or the paper). I cannot draw a well resolved square line without a number of circular dots to draw it with.

  • TY

    Just stop the DPI race. I would rather have lower GPU stress than having those extra pixels I can only distinguish when I am so close to the screen I erosion l worsen my eyesight. Motorola gets it. Ubuntu gets it. Come on, the others. At least offer an option!

    • miri

      The point of high density is that you can't distinguish the pixels.

      • TY

        I mean, we need to stop somewhere.

        ~300ppi:

        Indistinguishable at >25cm (which is the minimum distance for you to not get short sighted very soon), unless you have perfect eyesight.
        Slightly distinguishable 5cm

        The 30ppi>400ppi jump is already only slightly noticeable.

        How about 500? 600? Is that really needed? You must understand that more pixels = more GPU load = less battery and performance. Also, for LCDs, more pixels = more barriers between pixels = stronger backlight needed = less battery/less brightness. (I'm not sure about OLEDs).

        I would prefer ~300ppi all day. Some may prefer ~400. But we must stop somewhere until it becomes a totally meaningless race.

        • miri

          It's not quite that simple, actually. You're forgetting about contrast between the pixels. In certain situations (3D graphics, tiny text, etc.) pixels are very visible even at ~300ppi and even when they're not, studies have shown that an increase in density, even beyond perception has gives the display an "intangible sense of depth and realism". This conversation is meaningless anyway. The advancement of technology goes well beyond our petty wants in a phone. The minimization of tech is ALWAYS a good thing and when there's nothing more to do or the next big thing comes along, then we'll move on to something else. Ice cream.

        • phila

          what you're basically saying is "Apple got it right by not bothering to push technology any further after Steve died"

          once you use a 440+ ppi screen, looking at a 330ppi screen and it actually looks worse

          technology ALWAYS pushes forwards - if you want to stop, you're basically asking it to stagnate, which companies won't do!

    • GraveUypo

      i agree. it's stupid race. only makes things waste more battery and get more expensive for no good reason. 720p is the sweetspot for phones imo.

      • Prasad Tiruvalluri

        I don't know. SJ perpetuated this myth that anything greater than 320 DPI is not perceived by the eye. That is downright wrong -

        http://www.cultofmac.com/173702/why-retina-isnt-enough-feature/

        • GraveUypo

          i can look at 1080p screens side by side to 720p of similar size anytime i like. they're slightly better up close, but i wouldn't pay a extra dime for them.

          btw i can see some pixelation on 1080p phone screens too from a normal distance, depending on the displayed images (a good, easy place to look for that is the wifi icon, for one). the thing is, 720p is enough to display a crisp, detailed image. and that's not restricted to small screens. 720p has a good enough amount of pixels to compose a image, unlike lower resolutions, which no matter how big or small, you can never see a decent amount of detail on pictures.

          i watch stuff on a 100" screen projected screen at 720p at night in my room and it looks good ffs.

          and while they focus on packing more and more pixels on the same small area, stuff that really needs work stays the same gen after gen, even when talking solely about screens, let alone the whole package. it's stupid.

    • robert wilson

      so i should be stuck looking at blocky graphics because you're blind?
      when we get to the point that anti-aliasing is no longer needed, then you can start talking about "extra" pixels.

    • dsass600

      1080p is really the highest we need to go.

      • didibus

        Relative to the size of the display though...

    • Sergii Pylypenko

      Mr. Torvalds would disagree with you (the post is about Chromebook Pixel)
      https://plus.google.com/102150693225130002912/posts/TDMUKQw3Lif

  • NF

    I'm calling GTV for 4K coming soon.

  • Spittie_

    I the meanwhile, in desktop land, 100 DPI is already a lot.

    • gosa

      Yeah, exactly... this is something I still don't understand. People are sitting with their 4-5" mobile phones complaining about low dpi, and then they spend hours and hours in front of their computer monitors.

      I'm reading that the new Nexus 7 is going to have a 1900-something resolution on it's 7" monitor, and here I am thinking that I took an acceptable step "up" from the 10"- 1024-600 on my netbook when I bought my Memopad 10 with it's 1200x800 on the same screen size...

      • Mantas

        Computer monitors are usually 5 times further from your face, so it's logical that the dpi could be lower

        • didibus

          I would not say 5 times, 2 times further is a better approximation, sometimes mine is even closer. Though the screen is many times bigger.

  • theineffablebob

    3840x2160 is actually 4x 1920x1080, not 2x.

    • Sonnyrock76

      Really? I must not understand how resolution mathematics work. Let's see ...3840÷2=1920 right? 2160÷2=1080 right? So 4K is 2x 1080p...I am right aren't I? Or am I missing something?

      • LAKAME

        Yes. 4K has 2 times the width and 2 times the length of 1080p. Those 2s are multiplied -> 2x2=4.

        • Guest

          Think of it as 4 HDTVs arranged in a block

      • A$AP Chris

        Think of it as 4 HDTVs arranged 2x2. 3840 pixels long, 2160 pixels wide

      • Luke Skaff

        Couple things here, it is called 4K because its horizontal resolution is approximately 4000 lines. Now it is also four times the resolution of 1080p: 1920*1080 = 2,073,600 pixels, 3840*2160 = 8,294,400 pixels.

        • andy_o

          Resolution is measured linearly, e.g. line pairs/mm or line pairs/picture height. that means that 2160p is only twice the resolution of 1080p. Resolution is not the same as number of pixels, even though most tech sites use the term colloquially, incorrectly and probably unknowingly, IMO.

          • MeCampbell30

            Stop. Pixel resolution is always measured by columns and rows. A 4K TV has 4 times the pixel resolution of a 1080p display. It's that way because on an RGB display spatial resolutions scales with pixel density.

            The reason line pairs are used in other applications (like photographic lenses and tube TVs) is because colors from one arbitrarily small area bleeds over into other area. Thats why you stick a lens chart in front of a camera and measure how far down the chart you can read before the image gets blurry.

            http://www.normankoren.com/Tutorials/Lenstarg_lin_720.png

          • andy_o

            In this case the term "resolution" has been misappropriated. What does number of pixels tell you about the display's or sensor's ability to resolve? (For instance, is 1080x7680 also 4x the resolution as 1080p?)

            You bring about pixel density, and that can determine resolution because it is also linear. 200 PPI is twice the resolution than 100 PPI. But 200PPI will have 4x the pixels than 100PPI with the same aspect ratio. Use your own example with a 4K (2160p) TV, and calculate the PPI if the displays were the same size. It will only be double.

            Number of pixels is not a measure of resolution per se.

          • didibus

            My understanding is that, resolution, is a measure of precision normally, but many types exists. Spatial resolution, pixel resolution, display resolution, etc.

            But in the context of digital displays, we use Display Resolution as pixel dimensions. So 3840x2160 is 4 times the amount of pixels per image compared to 1920x1080. Notice that this measure does not tell us the size of the pixels. It does however tell us the aspect ratio of the pixels, which pixel density does not. Size of pixels is told by PPI, pixel per inch. PPI can not tell you the pixel resolution, neither the aspect ratio. It is true however, like you said, that Display resolution is used for many a thing, but nowadays, I'd say it pretty much means pixel dimensions, even if it should more accurately have referred to PPI, since only PPI tells us how precise a display is.

            Wikipedia:

            The term “display resolution” is usually used to mean pixel dimensions, the number of pixels in each dimension (e.g., 1920 × 1080), which does not tell anything about the pixel density of the display on which the image is actually formed: broadcast television resolution properly refers to the pixel density, the number of pixels per unit distance or area, not total number of pixels. In digital measurement, the display resolution would be given in pixels per inch. In analog measurement, if the screen is 10 inches high, then the horizontal resolution is measured across a square 10 inches wide. This is typically stated as "lines horizontal resolution, per picture height;"[1] for example, analog NTSC TVs can typically display about 340 lines of "per picture height" horizontal resolution from over-the-air sources, which is equivalent to about 440 total lines of actual picture information from left edge to right edge

      • GraveUypo

        reading things like this i wish they would do the logical thing and use the same fucking name scheme they use for pictures. 4k screen should just be a 8mp screen.

      • m4570d0n

        Yes. 5th grade math class. ;)

        • miki

          Yes, but in terms of scale (keeping aspect ratio) it's really double; you're moving both axis at the same time. It doesn't mean it holds 4x as much pixels.

      • Nomaan

        the double of 1920x1080 would be 1920x2160....................8x2=16 and ............16x4=64 and not 32

      • ergu

        You're missing the fact that area is two dimensional. This is a common mistake. Here's a way to put it in perspective, if you had a square canvas of 100mmx100mm, and you multiplied ONLY its width by 2, you would double the amount of canvas you had previously. If you multiplied the width of original 100mmx100mm by 4 (the same as multiplying both height and width by 2), you would have 4 times the original area.

      • didibus

        (3840 x 2160) ÷ (1920 x 1080) = 4

        (4 x 4) ÷ (2 x 2) = 4

      • http://dexxtr.com/ Kuskov Alexander
    • Simon Belmont

      THIS! I see this mistake pretty often online.

      People have to think about it in TWO axes (x and y), and not just one. The graphic below that m4570d0n posted perfectly illustrates the concept!

  • fredric

    New means of eyejaculation on Android!

  • dilharo

    Since Google TV merged to AOSP starting from 4.2.2, this only makes android vision clearer...One OS runs everywhere!

  • Howard Bamber

    This pissing contest has to stop .
    We have GONE past where phones need to be .

  • William Riyanto

    lol at the commit message.
    Implement issue #6646859: 4K!!!! 4K!!!! 4K!!!!

  • Waleed Al Suwaimel

    I saw the headlines "Android 4.3 code reveals 4k" in my RSS feed on the Verge and Engadget first but I just knew somehow that the source was going to be the Android Police. :D

  • Elliot Kotis

    Nexus 10 2013!!!!

  • anzensepp1987

    Note 3! Will have a 4k-resolution! And the battery will be carried within a backpack... ;)

  • Karlo

    If im correct then PPI would be 882

  • John-Smith

    Are we even ready for 4k? We just started getting 1080p on smartphones, lets give it some time for 4k. My laptop/internet connection can't even handle watching a 4k youtube video.

    • http://www.anivision.org/ Christopher Bailey (Xcom923)

      hell my 17.1" PC has a lower rez than my 10" tablet. Mobile is going faster than PC it's unfortunately we'll have to deal with that.

  • John Smith

    And this is another reason why the APK size is dramatically growing. M/HDPI devices have no need for the extra high resolutions, but the APK contains them nonetheless; it's a lot of wasted bytes that are downloaded.

  • Simon Belmont

    "A typical use of this density would be 4K television screens --
    3840x2160, which is 2x a traditional HD 1920x1080 screen which runs at
    DENSITY_XHIGH." Hate to say this, but it's actuall 4x the resolution of FHD.

    It might look like it's 2x because the numbers are doubled, but you have to remember that it's doubled on both the x and y axis. So, it's really four times the resolution. It would only be doubled if ONE of the axes (x or y) were doubled, but not both. It's a common mistake.

  • Mark Buikema

    I tried to put an xxxhdpi launcher icon in my app but eclipse gives an error. Any tips anyone?