Re: Screen Colours / Color Depth: 16 million or 65K?
 

yeah i can see that. I want to know why this happening too! May be the application doesn't use hardware rendering?

But there are other devices out there listed as 16.7mil colours. Even the iPHONE 3GS spec say 16.7mils colour offially on their page.

can someone explain why isn't N900 spec say the same as the iPhone? though i can see that N900 has better clearer screen when comparing it side by side.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

It's called "marketing" or in other words how to lie to you so that you buy their ****.

http://www.displaymate.com/iPhone_3GS_ShootOut.htm quote:
"The iPhone uses 18-bit color, which provides 64 possible intensity levels for each of the Red, Green and Blue sub-pixels that are used to mix and produce all of the on-screen image colors."

16M colors listed on iPhone page is a number of colors used on software level, but when it actually being drawn to a screen it is converted to 18 bit image with dithering (google for that word finally!).

A good example is a black and white newspaper photo which only uses black ink, but due to the way it is used your eyes actually see a gradation of gray color - now take a magnifying glass and look at the way it is done.
Some spots are completely black, some are completely white, but some have small dots of both, so depending on how many of those near your eyes see it as some sort of gray. Dithering on your screen is similar, yet not the same as in newspapers.

N900 screen has higher resolution and therefore higher dpi - reason it looks better.

Read some wiki on how digital images are displayed on screen, then you'll understand better the difference and can actually decide if screen depth is as important as you claim it. Don't get me wrong, it would be cool to have a 24 bit, but as long as screen is only 18, making software calculate more than that won't make much difference.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Some higher quality LCD screens do have more depth than TN does. I am a luck person with a IPS-based display and it shows true 24 bits of color.

IRC, Apple has chosen an IPS based display for its iPad, too.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

You said it: you were lucky. It's not common.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

The actual color format is 5+6+5 in the N900 (otherwise you don't actually get 65k colors), but excellent post either way.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Probably the desktop app pre-process the image with its own renderer using dithering algorithms to give it a smoother finish. Which actually is reasonable - those images don't change frequently enough so a bit overhead when adding them to desktop is quite acceptable - and since those are the images that users will most frequently see there is a reason to do that from a marketing/general user experience point of view.

You can see a City Bank written on a bus, that doesn't mean that you'll get any money if you enter it. iPhone has way worse screen than the N900 - color depth is the same, N900 has 2.5 more pixels thus resulting in far crisper image and especially text, and the N900 has better viewing angles (actually I'm quite surprised how good it is at that given that it uses TN-Film which by itself has abysmal viewing angles which only get worse as the dpi rises, and N900 probably has the highest DPI I've ever seen on an LCD).

Oops :o, I stand corrected. I forgot to consider that for the sake of color uniformity as the debate started on white-to-black gradient where additional bit to any of the colors plays no role except giving it a hardly noticeable tint. Yep, when limiting a screen to the 16-bit (or any other depth indivisible by three) you need to give an advantage to one of the colors to have 65k colors available, but when considering a grayscale we can safely say that the screen actually performs as 15-bit, which is precisely the reason why there are 32 distinguishable bars on a full white-to-black gradient.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

The Neo 1973 & FreeRunner still beat it :-)

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Yeah, unfortunately it is not common. You have to search for an IPS or PVA based monitor if you want 24 bits. It is even harder than that because most companies that sell those are available only in Europe, with just a few in the US. If you live somewhere else, you have to import it (a lot of trouble).

Anyway, current large TN panels seems to do 24 bit colors by doing hardware dithering (either spacial - rare or time-based dithering - more usual). That way, they "present" a 24bit interface to the OS and the user sees a good approximation of it.

It would be interesting in checking if small panels for cellphones would also be sold with controllers capable of hardware dithering. Although for it to work, the Operating System would have to send 24-bit color instructions instead of only 15 or 16-bit. Since the OpenGLES engine only seems to work at 16-bit colors mode, for the N900 there is no point, aside from curiosity.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Some tests I did here with the N900,
The result was a Next.
View a photo to the gallery of photos, it displays in 16bit
And the image display on the desktop, or videos he shows up at 32 or 24 bits.

Fassa the test, I created a video with a photo posted here.
Fassa Download and test.
The video is in 800x480 30FPS 5.5Mbps/s . MPG4

http://rs465.rapidshare.com/files/37...test_Video.zip

Turn the Video with MPlayer, It better!

Thank you all! ATT: MAYKON

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Therefore, it is clear the N900's screen is capable of playing much besides just 65K colors!
The problem is the gallery of photos, which renders Images Only 16bits. The same technique used to navigate the web.

And for playing videos he renders with Over 16 Bits No doubt! Reaches 24 bit Color Video In fact it is!.

The question is? such a limitation of 16 bits Imposed by the photo gallery and the configuration of Maemo5 or photo gallery that renders only 16bit?

By remembering that put the image on the Desktop of the N900 image is displayed with 24 bits.

Ate more! Thanks!

Re: Screen Colours / Color Depth: 16 million or 65K?
 

How did you reach this conclusion? Most likely explanation for any differences is that the desktop and video player do dithering, while the photo gallery (for some reason) does not. Try taking (lossless) screenshots of a color gradient on both and compare those.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

No, all that shows is that the dithering on the desktop is far better than that in the image viewer (to the point where you can't see the any effects). You'd need to get a screenshot of that image, load it into a decent photo editor, and get a count of the number of different colour values (and that assumes that the screenshot is taken from the display post-processing).

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Did downlaod the video that I mounted to test? http://rs465.rapidshare.com/files/37...test_Video.zip
This video is in 32 Bit Color

Image to 32 bits in color http://talk.maemo.org/attachment.php...1&d=1269562974.

See the difference! Take the quiz! Rotate Video in Windows Setup in 16bits

Then rotate Player Of The Nokia N900.

Soon after, Turn Video On PC With Windows running on 32bit!

The Comparable is that the video running on 16 bit Windows, you become like the image appears in the photo gallery of the N900.

And when we shot the video in Windows with 32bit, It is identical to the Video Video Player running on the Nokia N900. And the identical image appears on the Desktop Do N900.

Thus we conclude that the N900 generates images with more than 65K colors! No doubt!

Re: Screen Colours / Color Depth: 16 million or 65K?
 

No, we can conclude that dithering in 16-bit windows is poor, which is unsurprising as there's probably near-enough zero people who've ever used it. Anything else is still supposition.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Curiosity! I did a test using the Nokia 5800, it displays the image in your gallery with a definition of colors higher than in the N900!

nokia 5800 in the image Appears in 32bits!
The same image as the Nokia N900 appears in 16bits!

How do not understand how powerful a device Nokia N900, shows photos in only 65K (16bit) colors!

While the Nokia 5800 Display Images in 32 bits, or near!

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Here we go again... There is no such a thing as 32bit color depth on a monitor. None! Zip! Nada! Please, educate yourself: HERE.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Nice haiku!

Didn't understand a thing unfortunately :(

Note that there's indeed a chance the media player uses a greater depth (the _media_ player, not the photo gallery nor the desktop background since both use the sgx).
I'd still like some kind of image I could use to test if the output is 16 or 18bpp.
I have quite a few things (let's say knobs) to test but as I said I have no way to tell if the actual output is 18bpp or the system is just lying to me.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

http://www.nokia.ro/produse/cautare-...i#hardware-dui
nokia.ro romania
and
http://www.nokia.fi/tuotteet/kaikki-...e#hardware-dui
nokia.fi FINLAND

Re: Screen Colours / Color Depth: 16 million or 65K?
 

The Nokia Finland link translated to English:

http://translate.google.com/translat...ui&sl=fi&tl=en

Re: So, how to change the depth?
 

Short answer, nope, it doesn't work - or at least it didn't for me. You'll end up in the good old endless reboot cycle : (

You probably don't want to be doing that.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

I imagine the proper way of doing it for backwards compatibility would be to mess with the video driver to make it so when a program tries to make the screen be 16bits, padding is added as the least significant bits of each color component to produce a 32 (or 24 or whatever) bits image; the programs would think they are making the display be 16bits when actually everything is more bits all the time. Unless, of course, it is actually easy and trouble free to change bit depth each time a program wants a different one.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

when using opengl you can clearly see that the display depth is 16bit. if you display a number of 32bit textures with an alpha channel there is a lot van color banding.

i would love to know how to set the bitdepth to 32bit when using an QGLwidget. But i think you would loose the ability to view a thumbnail of your application when multitasking and the ability to see the alerts (like the yellowbar for the volume), since these are composited in 16bit and i don't think you can mix those.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Oh, of course you can -- in fact, you can actually do 8+8+8+8 rgba surfaces and hildon desktop will take proper care of the alpha values up to the point it will actually composite the background with both your actual window and the thumbnail.

I do not know how to do it with QGLWidget, though.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

I just found out how!!

And it is REALLY simple!
you can start yourQt application in 32bit mode by adding the argument "-visual TrueColor"
Works perfectly, all the banding problems are GONE!!
This really should be known by anybodu who is writing OpenGL games in Qt for Maemo.

http://doc.trolltech.com/latest/qapplication.html

Re: Screen Colours / Color Depth: 16 million or 65K?
 

The composited output is still 16bpp, and the banding is not gone (look closely).

Also, I suggest you don't do this because it will be even more slow.

Re: Screen Colours / Color Depth: 16 million or 65K?
 

The composited output maybe 16bit, but my banding problem is definitely gone. It isn't directly related to 16 bit output, but to loading textures as 16bit, and that kills the alpha channel

just have a look at the blue nebula in the background:
http://dl.dropbox.com/u/6050252/16bitQGLN900.png
http://dl.dropbox.com/u/6050252/32bitQGLN900.png

So yes it did solve my problem :)

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Check the following link to get detailed specs about the N900:

http://pdadb.net/index.php?m=specs&i...00_nokia_rover

Hope this will be helpful to all...


RSVR

Re: Screen Colours / Color Depth: 16 million or 65K?
 

hmm, wonder if it can be applied to the kernel ... ? it has to be a battery issue ..

Re: Screen Colours / Color Depth: 16 million or 65K?
 

I have a few questions about this...

It seems the screen is fixed to 18bpp and software is generally written in RGB565. Obviously, a h/w limitation many devices are subjected to. On the device, that's fine because the pixel density is quite high and everything generally looks quite good.

- I'm not clear as to whether the frame buffer is similarly limited or can it handle True-Color (or whatever it's called)? Indeed, is that what the much-touted specs really refer to - the SGX530 can render 16M colours, even if the screen can't?

- The reaason I ask is when an external screen, capable of displaying 24bpp, is used in lieu of the standard one, can the graphics hardware cope even if the display cannot?

- Can data go straight from the frame buffer to the out channel, without going to/via the screen, thus no need to be interpolated down? (out channel could be any, not just the normal tv-out e.g. BT, wifi, etc).

- Can the frame buffer render different sizes/proportions to that of the screen? Again, if connected to a different screen, this would be ideal for running desktop applications. Not much more, say 1024 x 768. Though, the N900 might have to live in a bucket of dry ice to do this!

Incidentally, those green artifacts that appear on embedded video streams - do they occur because of the 888 - to - 565 conversion?

Re: Screen Colours / Color Depth: 16 million or 65K?
 

Tbh, I'm not still sure what the screen depth is. The device software is configured to 16bpp, and possibly makes that assumption in some closed places noone knows. But Hildon works on 24bpp. That's tested easily on a PC.

Yes. Also, the Pre1 does 24bpp.

Well, no real idea here... probably can be answered with a lookup to schematics.

Yes -- you're not transferring uncompressed 800x480 at 24bpp via wifi, though. So you will have to use some compression, like VNC, or NX. In which case, 24bpp is more like a nuisance...

Of course. And no bucket of ice. Remember this is pretty much like a desktop GNU/Linux after all.

Na, video is not rgb888, but usually YUV.