Adjusting for "overscan" on DLP while maintaining 1:1 pixel mapping? - Page 2 - AVS Forum
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post #31 of 52 Old 02-26-2012, 01:23 PM - Thread Starter
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Honestly, they are overkill. My room isn't very big. I started off with a pair and really liked them. When I redid some things I thought I'd rebuild the sub into a taller tower, doubling up to a quad. It's nice piece of mind knowing that I can throw whatever I want at it without worring about bottoming them out, but I wasn't really hurting for output before. Brian helped me with some mods to the amps so that one acts as the master and the other three are slaves (phase, volume, crossover are bypassed on the slaves). With four of them, the gain needs to be set so low that the auto-on on the slaves wouldn't trigger unless the volume was turned way up. I ended up having to leave them in manual-on mode, and wire up a switched outlet for them. But I do love them. It's the one componet I have that I may never have a desire to upgrade.

As far as this whole pixel mapping thing... I'm starting to think there's no easy answer. Perhaps my memory is bad and it's never autoswitched.

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post #32 of 52 Old 02-26-2012, 01:41 PM
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Quote:
Originally Posted by Darin View Post

As far as this whole pixel mapping thing... I'm starting to think there's no easy answer. Perhaps my memory is bad and it's never autoswitched.

Do you have access to an Intel build?

The reason I ask is because I also have a DLP and the ATI drivers drove me absolutely nuts. Then I switched to NVidia and it was a little better but still not perfect.

After about a month with the NVidia 430 I decided to upgrade my Core2Duo system to a Sandy Bridge and decided that I would try the stock Intel HD2000 graphics. Well, that was probably a year or so ago and I haven't looked back. The PQ was exactly the same (or so small a difference was present that I didn't notice) but the driver experience and stability was INCREDIBLE compared to the other 2 options I tried.

Now this is my experience so YMMV. It may be the same or it may be completely different. But if you have access to an Intel build it might be worth a shot on your DLP.
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post #33 of 52 Old 02-26-2012, 02:07 PM - Thread Starter
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Well, yes and no. My parents live in my rental house next door, and are on my network. I built an HTPC for them using an i3 so they have access to all my movies. While I'm sure they wouldn't care if I swapped with them, there are several things about mine that I prefer, and swapping between cases would be a bigger PITA than you would expect (mine is an odd build).

But just for curiosity, are you saying that on the SB setup, you can resize the desktop to account for overscan, but TMT uses the full 1920x1080? The current version of TMT doesn't allow for the automatic refresh changer on nvidia systems, but I'm wondering if I could use that to my advantage if/when they allow it. Since virtually all movies are something other than 60hz, maybe I could make 1842x1036 60hz only, forcing it to use 1920x1080 when switching to a different refresh. Though honestly, I don't know why TMT doesn't have its own resolution setting. Games have had that for decades.

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post #34 of 52 Old 02-26-2012, 02:19 PM
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post #35 of 52 Old 02-26-2012, 02:35 PM - Thread Starter
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Yeah, I suppose I could do that. What has your experience with it been? Are you able to get the desktop to fit into the visisble area w/o compromising 1:1 during video playback?

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post #36 of 52 Old 02-26-2012, 02:55 PM
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Quote:
Originally Posted by Darin View Post

Yeah, I suppose I could do that. What has your experience with it been? Are you able to get the desktop to fit into the visisble area w/o compromising 1:1 during video playback?

Desktop is a little off. A little overscan mainly at the top. This has been consistent on all 3 vendors on my Samsung DLP (without LED light engine)

Playback is perfect. Or so close to perfect that I don't notice that its not perfect.
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post #37 of 52 Old 02-26-2012, 03:26 PM
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You cannot get true 3D 1:1 pixel mapping of 1080p per eye if you send checkerboard format since it consists of a single 1080p buffer where 1/2 of the pixels are for the left eye and the other 1/2 of the pixels are for the right eye. You will see a 1080p image for each eye since the RP DLP fills in the empty pixels for each eye using interpolation between the content of the surrounding pixels. The RP DLP then uses wobulation to display separatly display the content for each eye.
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post #38 of 52 Old 02-26-2012, 03:33 PM
 
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Quote:
Originally Posted by Darin View Post

I really don't think that's true. You think my display supports a 1842x1036 input? Or 1840x1036? Or 1840x1034? Using the desktop resize controls in the video drivers, I can come up with any number of odd resolutions. The TV can only accept a handful of standard resolutions. All you're doing when you adjust this setting is changing the resolution Windows uses internally for the desktop, while the output remains at a standard resolution. Similar to the way some drivers will allow you to set a desktop size larger than the resolution being sent to the display, and panning as the mouse gets to the edge. But in reverse.

That was the case back in the day of ANALOG output via YPbPr. Back then you would do sorta what you're saying by adjusting the front/back porch etc. The DLP even though the screen is optical in the sense of the way it's projected still is inherently a NATIVE DIGITAL display device and as such when you use your display driver to create custom resolutions do understand they are sent as those strange resolutions.

You're problem sounds like you have graphics card device scaling turned on for non native resolutions. I'd turn that off and allow the display to do this.
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post #39 of 52 Old 02-26-2012, 04:26 PM
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on the old drivers, when I resized my desktop, if I went into some programs, I would end up seeing things with borders and such when their shouldn't be borders? is this what you are seeing?

clearly I still haven't seen you say that it works or doesn't work without resizing the desktop, I know I resized my desktop and when i go back to resolution, it is not using a custom sized resolution in the list of resolutions. if it is, then that is why things are wacked out.
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post #40 of 52 Old 02-26-2012, 05:06 PM
 
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I think he has GPU scaling turned on but is having issues understanding how to adjust or set it to off in the control panel...

just my opinion...

or ITC or what ever nVidia calls the same feature for LUT tables choice based on stream or EDID. I know this shouldn't affect scaling but I've seen weird driver behavior related to this and how it reads EDID or the EVR stream and makes sink signal decisions in driver code.
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post #41 of 52 Old 02-26-2012, 05:07 PM
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I believe that's an amd setting not nvidia
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post #42 of 52 Old 02-26-2012, 05:10 PM
 
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Quote:
Originally Posted by robl45 View Post

on the old drivers, when I resized my desktop, if I went into some programs, I would end up seeing things with borders and such when their shouldn't be borders? is this what you are seeing?

clearly I still haven't seen you say that it works or doesn't work without resizing the desktop, I know I resized my desktop and when i go back to resolution, it is not using a custom sized resolution in the list of resolutions. if it is, then that is why things are wacked out.


That's related to font DPI exceeding the edges of windows GDI oject/elements. It results in the text not fitting within the confines of a windows control element. It then graphically truncates the bottoms of the font.

You know guys windows is so primitive in many ways compared to the *nix desktop environments!
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post #43 of 52 Old 02-26-2012, 05:21 PM
 
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Quote:
Originally Posted by robl45 View Post

I believe that's an amd setting not nvidia

ITC?

Yeah

But not scaling decisions IE display or adapter. That's a feature of ALL display drivers if it's sending a digital TMDS signal.
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post #44 of 52 Old 02-26-2012, 07:14 PM
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i just tested on my monitor here but i think it works a little different when connected by hdmi, at any rate, when i resized the desktop, it put a custom resolution in the settings, but then i could go and select the normal resolution of 1280x1024 and it changed to reflect that but still kept the desktop at the size i set.
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post #45 of 52 Old 02-27-2012, 01:41 AM
 
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Quote:
Originally Posted by robl45 View Post

i just tested on my monitor here but i think it works a little different when connected by hdmi, at any rate, when i resized the desktop, it put a custom resolution in the settings, but then i could go and select the normal resolution of 1280x1024 and it changed to reflect that but still kept the desktop at the size i set.

That just tells me you have GPU scaling turned off and also turned off in your display device and that you've made an "overscan" adjustment. I guess your right in saying that technically it's still sending a 1080p spec signal it's just blanking lines and doing GPU scaling to achieve the underscan to make it fit.

At this point I'm feeling rather ignorant about nVidia's offerings as of the last couple of years.

With AMD you can achieve under or overscan a few different ways. The overscan % slider basically does a underscan scaling in GPU thus sending blank lines to make the image fit but within standard timings/signal. There is also the ability to create custom timings and resolutions. Of those two ways of doing it there is also scaling option for doing it in the GPU or the display device. To do it with centered timings or with it maintaining aspect ratio.
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post #46 of 52 Old 02-27-2012, 04:21 AM
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Quote:
Originally Posted by Solid-State View Post

That just tells me you have GPU scaling turned off and also turned off in your display device and that you've made an "overscan" adjustment. I guess your right in saying that technically it's still sending a 1080p spec signal it's just blanking lines and doing GPU scaling to achieve the underscan to make it fit.

At this point I'm feeling rather ignorant about nVidia's offerings as of the last couple of years.

With AMD you can achieve under or overscan a few different ways. The overscan % slider basically does a underscan scaling in GPU thus sending blank lines to make the image fit but within standard timings/signal. There is also the ability to create custom timings and resolutions. Of those two ways of doing it there is also scaling option for doing it in the GPU or the display device. To do it with centered timings or with it maintaining aspect ratio.


this is just standard options in the nvidia control panel to resize desktop and change resolution. and my computer monitor doesn't have any overscan settings. none that I ever seen for sure.
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post #47 of 52 Old 02-27-2012, 05:28 AM
 
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Quote:
Originally Posted by robl45 View Post

this is just standard options in the nvidia control panel to resize desktop and change resolution. and my computer monitor doesn't have any overscan settings. none that I ever seen for sure.

Interesting robl45 thanks for taking the time to test and share that info...

This place is a treasure trove of info if you just exhibit the right attitude ehh!

And find the right users...

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post #48 of 52 Old 03-12-2012, 06:39 PM
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Reality is this:
When you are displaying a PC via HDMI on a Mitsubishi DLP TV, after overscan, your Mitsubishi DLP is a 1824x1026ish monitor… overscan is there both because of being projection and being broadcast tech based.

Q&A:
Q: Can I adjust out the overscan on a Mitsubishi TV to get the entire 1920x1080 fit to the screen so I can set my PC to that resolution?
A: NO…. the service menu doesn’t allow that adjustment, only keystone (edge geometry), and centering.. the remote ‘format’ button will allow you to set ‘reduce’ mode that puts the whole 1920x1080 on the screen, but it UNDERSCANs it dramatically leaving a few inches around the entire image… there is no 1:1 adjustment like you see on direct display sets like LED / LCD.

Q: is it really that bad a problem?
A: IMO, No … especially if you have an Nvidia card… here’s what happens with PC content:
1- you start with a content file encoded with H.264 or whatever
2- you have a codec installed that decodes that stream in conjunction with your Nvidia video card
3- Nvidia cards have PureHD which is basically a hardware decode engine that takes your content stream (I'll remind you that video cards are very high performance PCs these days)... decodes it on the video card, AND does high performance image enhancement on the fly. ATI and Intel have this also, but after watching the driver race for a decade, I’ll take the Nvidia image any day.
4- it does that work and then combines that with high performance SCALING to match whatever display size you have selected by sizing your vid player window or making it full screen ... this is an important point... so it takes 1920x1080 content, enhances it, does a very high performance scaling to 1824x1026 or whatever you have set, then sends it to the TV
5- your TV displays a 1:1 pixel view of the 1824x1026 enhanced image, eliminating issues with projection scaling etc.

I like the 1080 and 720 output of my Mitsu in this scenario, a lot... and I also like the projection / film like quality of playback which you don't get with the harshness of an LCD / LED, but that's a whole other discussion.

Lastly, I'll point out that a lot of HD content is still 720 anyway and is thus getting upsampled by the TV, Player, or PC anyway so I'm not really uptight about getting my full 1080 1:1....

I have a lot of 720 and 1080 and 1080 bluray content that I have compared on this setup vs a regular 1080 LED and I'll take the Mitsu every time... also I'll point out that the Nvidia 720 upscale is so good I am unable to tell the difference from 1080 bluray almost all of the time.
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post #49 of 52 Old 03-13-2012, 10:46 AM - Thread Starter
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Quote:
Originally Posted by stmckin View Post

there is no 1:1 adjustment like you see on direct display sets like LED / LCD.

Well, there is, it's just not labeled as such, and you have to go into the service menu to get it. If you disable geometry correction, you get 1:1 pixel mapping. Of course, that does leave the edges of the image outside of the screen area.

Quote:


Q: is it really that bad a problem?
A: IMO, No … especially if you have an Nvidia card… ... it takes 1920x1080 content, enhances it, does a very high performance scaling to 1824x1026 or whatever you have set, then sends it to the TV ... your TV displays a 1:1 pixel view of the 1824x1026 enhanced image, eliminating issues with projection scaling etc.

But if it's scaling the original image, it's not really 1:1 pixel mapping. You can't take something that starts off at 1920x1080, and ends up at 1824x1026, and call it 1:1 pixel mapping unless you are cropping the image (which is effectively what is happening with overscan). The loss in resolvable detail is noticeable, despite whatever "high performance scaling" is being done by nVidia. There's no getting around the fact that interpolation is a lossy process.

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post #50 of 52 Old 03-13-2012, 11:16 AM - Thread Starter
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Quote:
Originally Posted by assassin View Post

I meant just to test it. Not to keep.

By the way, since this thread has been "revived", I never responded to this... I did try to test this. I realized I didn't really need to drag their HTPC back to my house, I could just test it on their system. I could simulate overscan on their LCD display by using the Intel drivers to shrink the image down smaller than the visible area, then play back a movie with TMT to see if it stayed within the shrunk area, or used the full screen. But I never figured out how to do the overscan adjustments in the Intel drivers. I saw a way to create a custom resolution, but never got it to apply. But they were yacking at me the entire time, so I gave up earlier than I would otherwise. But this is something I'll have to work on some more this weekend, as I just got them a new TV (it's a Mits RPTV as well). I need to make sure I have the latest Intel drivers on their system. Perhaps the settings just aren't there on the version I have on there, or perhaps I just didn't look hard enough. They are out of town this week, so I hope to get a stand built for them and get the new TV put in by this weekend. Then I can play with it some more.

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post #51 of 52 Old 03-13-2012, 11:18 AM
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Quote:
Originally Posted by Darin View Post

By the way, since this thread has been "revived", I never responded to this... I did try to test this. I realized I didn't really need to drag their HTPC back to my house, I could just test it on their system. I could simulate overscan on their LCD display by using the Intel drivers to shrink the image down smaller than the visible area, then play back a movie with TMT to see if it stayed within the shrunk area, or used the full screen. But I never figured out how to do the overscan adjustments in the Intel drivers. I saw a way to create a custom resolution, but never got it to apply. But they were yacking at me the entire time, so I gave up earlier than I would otherwise. But this is something I'll have to work on some more this weekend, as I just got them a new TV (it's a Mits RPTV as well). I need to make sure I have the latest Intel drivers on their system. Perhaps the settings just aren't there on the version I have on there, or perhaps I just didn't look hard enough. They are out of town this week, so I hope to get a stand built for them and get the new TV put in by this weekend. Then I can play with it some more.

Try this...

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post #52 of 52 Old 03-13-2012, 11:29 AM - Thread Starter
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Thanks assassin, I'll check that this weekend. It was a few weeks ago that I tried on theirs, so I don't remember if theirs had exactly the same options (I built that machine over a year ago, so it probably doesn't have the latest drivers). But to be honest, I wouldn't have tried that option, as I wouldn't expect to look in something labeled "scaling" as a solution to get 1:1 pixel mapping. At the time I wasn't overly concerned about it, since it was just a test for comparison's sake. But now that I got an RPTV for them, I'm more interested in it, as my stepfather indicated he was interested in using the PC on a large screen.

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