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2012-08-05, 10:31
Hi there,
I'm using Openelec 2 beta 5, and it seems to include Fernetmenta's patches for vdpau. There are at least 2 options which are new to me:
Allow OpenGL VDPAU interopt RGB and interopt YUV
Does someone now what those options do? I'm using a sony TV which let you select colorspace and hdmi range (full or limited), does somebody know which options woukd be best? Any hints on why?
Thanks to all!
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2012-08-05, 17:13
(This post was last modified: 2012-08-05, 17:15 by FernetMenta.)
XBMC checks for e.g REC.709 and does conversion to full range.
EDIT: For VDPAU this means you have to activate VDPAU Studio level
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2012-08-06, 12:02
(This post was last modified: 2012-08-06, 12:03 by PatrickVogeli.)
Yeah, now that we have both FernetMenta and cowfodder here, we may finally know which settings are the best!
Ok, in my ION system, it seems clear that I have to enable RGB interop AND studio level correction. What about colorspace? We let it at RGB as by default, correct?
In my TV, HDMI level should be set to full range, what about colorspace? I can set it to auto, itu.601 or itu.709, what should it be set to?
And last, but not least, until now, I always disabled studio level correction because it was impossible to me to set the tv propertly. I use some basic Test disc found at AVSforum, with which you can adjust your tv to see some black/grey flashing bars on black background (brightness) and some white/grey ones on white background (to adjust contrast). But, if I remember fine, when I use that I always see all the black/grey bars, even with ridiculous amount of brightness, and with white it's even worse. And, of course, there's the problem with non vdpau material: setting the system for vdpau material with those corrections, will make non-vdpau material too dark and you loose lots of details.
Any ideas?
Thanks for your help! That could make it to the definitve thread of how to properly set up the nvida systems with modern TVs!
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XMBC output is RGB full range for GUI and video. Setting gfx to YUV makes no sense. You just convert back and forth. Currently vdapu stuio level determines color space by size of video. I will change this to obsering tags provided by ffmpeg in case we can trust them.
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2012-08-07, 22:09
(This post was last modified: 2012-08-07, 22:17 by PatrickVogeli.)
Definitely yes, enabling studio level means for vdpau material means I need different settings (brightness and contrast) for vdpau enabled material and non vdpau one, which is quite of inconvenient.
FernetMenta, any help on that one? Why is that way?
PD: I think I got it... VDPAU studio level converts the blu ray material to full range rgb while standard def non vdpau is output as is.. correct? If that's so... why don't we disable any vdpau color processing and adjust the display that way? That is, to itu 709 and limited hdmi black levels, which should be the same for nearly all video material. Sure the xbmc interface woukd be displayed differently (crushed blacks, grey whites maybe?), but at least all videos woukd share the same tv settings and should look fine, wouldn't they?
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VDPAU Studio Level ist not what it should be. I tried some test patterns and on my calibrated Plasma it gives me a incorrect image. Without it everything should be normal on a display that can process full RGB like every Panasonic Plasma or Samsung LCD TV...
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YUV to RGB conversion has to be done anyhow. Dependent on your setting it happens in different places:
1)
Software decoding (render method != software): done by OpenGL shaders
2
Software rendering: done by a function before rendering
3)
different hw accelerators
For 1) and 2) we have convertion matrices in order to handle the differeent color spaces.
If you don't select vdau studio level conversion, you'll get a standard conversion built into vdpau. Since vdpau does not know about the color space it can't apply the proper conversion matrix.
VDPAU studio level conversion provides a way for advanced applications like XBMC to influence the conversion.
If you observe incorrect colors when vdpau studio level is active, means that the matrices provided to the API are wrong or the colorspace of the input material is not detected right.
As I sayed erlier: Currently colorspace is detected by the dimensions of the inputmaterial SD is assuemed when width < 1000, hd when width > 1000.
With the re-write of vdpau I have also corrected conversion matrices which I think are wrong in current mainline version. This code has not been merged yet.
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Ok. So this means that at the moment the studio level option is broken due to incorrect matrices?
For me the black with studio level on is to bright and without it is perfect... material is AVCHD709 in .mp4 Format (1080p).
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I have exactly the same feeling! With studio enabled I must set my brightness to very low levels, which wouldn't that bad, but then videos.which don't use aVDPAU are too dark and the dark greys get lost because of incorrect brightness!
I really don't know what we are supposed to do.. I don't quite understand that technical talk
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Sorry for confusion. I had a look into the code: vdpau studio level conversion is wrong. Without this option conversion for bt 601 and 709 is done correctly. I think we should remove this option.