madVR - high quality video renderer (GPU assisted)

[nevcairiel]

Originally Posted by Qaq

IMHO, without RGB 4:4:4 full support all the talks about HQ chroma processing have no sence.

Converting 4:2:0 to 4:2:2 already doubles the chroma resolution, so there is that.
People always talk as if 4:2:2 is the worst thing ever, but its already twice as much chroma information as 4:2:0, and converting to that as good as possible is still better then doing a crap job at it.

[Qaq]

Originally Posted by nevcairiel

People always talk as if 4:2:2 is the worst thing ever, but its already twice as much chroma information as 4:2:0, and converting to that as good as possible is still better then doing a crap job at it.

I never said 4:2:2 is the worst thing ever, but I'm afraid downsampling 4:4:4 to 4:2:2 by some "black box" is. Do we still speaking of HQ processing, BTW?
I got your point btw. "HQ chroma processing" is really no big deal, correct? C'mon, tell us the truth )

[glc650]

Originally Posted by nevcairiel

My Sony TV has a mode that allows full 4:4:4 with RGB...

Which Sony do you have?

[DragonQ]

Originally Posted by Qaq

IMHO, without RGB 4:4:4 full support all the talks about HQ chroma processing have no sence.

PC monitors support full RGB 4:4:4 (unless it's a cheap TN panel with 6-bit colour channels and dithering).

[pankov]

Originally Posted by Heuer

Just tried that clip. 701 dropped frames in the first 5 seconds with a lot of stuttering and then played perfectly to end with no more dropped frames. Average rendering time was 16.03ms

Thanks
I guess it changed power states and when it was in the P0 it was enough to handle. Just barely but enough.
Can you check with GPU-Z if I'm correct?
If I'm not asking too much can you also check the GPU and Memory controller load and share your results?

[Qaq]

Originally Posted by DragonQ

PC monitors support full RGB 4:4:4 (unless it's a cheap TN panel with 6-bit colour channels and dithering).

Yeah, ppl with PC monitors pass color tests with better results than TV's ppl, but PC monitor is not an option for video anyway because of contrast, size etc.

[Dodgexander]

Originally Posted by ThurstonX

I was referring to the madVR setting under:

devices | [device] | properties | the display expects the following RGB output levels:

For my TV I set it to "TV levels (16-235)". OTOH, for my laptop I set it to "PC levels (0-255)". If I set it for PC levels when feeding my TV (with CCC set to Full RGB), then blacks get crushed.

But those are RGB inputs, not YCbCr. I take it you meant in your earlier post you set CCC too Full RGB along with MadVR, because asfaik theres no way to get Mad Vr to accept YCbCr.

Originally Posted by Prinz

And with this "Stuck Window" Bug the tray notifications also don't work correctly, even after leaving Exclusive Mode. Sometimes I get the tray notification an hour or so after leaving the Exclusive Mode. And the "Stuck Window" Bug happens also with all Apps on my PC for example: Taskmanager. I don't think that it has something to do with Browser, Flash, ...

Since the tray notifications also use a FadeIn/Out Animation, same bug I think.

I'm sorry to say it, but on windows 7 I do not get the problem with tray notifications, only with the stuck windows. And the stuck windows problem goes away once I disable the opening/closing animation.

I am guessing if you're on XP(and this isn't directed to you Prinz, but the XP users with the similar problem) and having the problem with stuck windows its a different kind of bug, perhaps as noted related to programs using hardware acceleration.

I only used flash as example, because it uses hardware acceleration, but perhaps more what is effecting it for you guys is the animations these programs have with dxva is enabled when closing/opening.

Perhaps changing some advance settings around in mad vr can diminish this problem for you?

On the subject of YCbCr 4:4:4, aren't Blu Rays and DVDs (& HD-DVDs) encoded in YCbCr?

Does this mean, (mad vr aside) that all pc software converts:

DVD & HDDVD YCbCr 4:2:0 too RGB
Blu Ray YCbCr 4:2:2 or 4:4:4 too RGB

And if you set your video driver to YCbCr:

DVD & HDDVD YCbCr 4:2:0 too RGB too (video driver)> YCbCr
Blu Ray YCbCr 4:2:2 or 4:4:4 too RGB too (video driver)> YCbCr

So this means on PC, there is no definitive solution, such as standalone blu ray players or even the PS3 to playback formats truly natively, providing of course your display supports it.

[nevcairiel]

Originally Posted by Dodgexander

So this means on PC, there is no definitive solution, such as standalone blu ray players or even the PS3 to playback formats truly natively, providing of course your display supports it.

Not even Blu-ray players can output it truely "natively", because Blu-rays are encoded as 4:2:0, and HDMI does not allow 4:2:0 transmission, but only 4:2:2, 4:4:4 or RGB.
Anyhow, your TV displays RGB, so at some point it needs to be converted, might as well be the PC. The only limitation here is that many TVs do their internal processing only in 4:2:2, so if you use any mode that does processing (most do), it'll use 4:2:2 as an intermediate step.

PS:
You get that wrong in your post, all commercial content is more or less 4:2:0, Blu-rays, (HD-)DVDs, Broadcasts .. only some satellite broadcasts use 4:2:2, but its not that common.

[Dodgexander]

Originally Posted by nevcairiel

Not even Blu-ray players can output it truely "natively", because Blu-rays are encoded as 4:2:0, and HDMI does not allow 4:2:0 transmission, but only 4:2:2, 4:4:4 or RGB.
Anyhow, your TV displays RGB, so at some point it needs to be converted, might as well be the PC. The only limitation here is that many TVs do their internal processing only in 4:2:2, so if you use any mode that does processing (most do), it'll use 4:2:2 as an intermediate step.

PS:
You get that wrong in your post, all commercial content is more or less 4:2:0, Blu-rays, (HD-)DVDs, Broadcasts .. only some satellite broadcasts use 4:2:2, but its not that common.

Thankyou, so what exactly is the point in 4:2:2 and 4:4:4 if blu rays don't use them, why have they been introduced?

For those confused like me, here is a good article to read.

[Zarper]

Originally Posted by Dodgexander

Thankyou, so what exactly is the point in 4:2:2 and 4:4:4 if blu rays don't use them, why have they been introduced?

For those confused like me, here is a good article to read.

YCC is created to compress the bitrate of the video. Because the human eye can see difference in light better then colours you separate them in to luma (Y) and chroma (C) channels and display the chroma channel in lower resolution.

4:4:4 is full resolution of both chroma and luma.
4:2:2 is full luma, full vertical chroma resolution, but only half horizontal chroma resolution.
4:2:0 is full luma and half chroma resolution.

Most videos are 4:2:0 to lower bitrate but the display have to upscale the signal to full resolution 4:4:4 to display it.

[Dodgexander]

Originally Posted by Zarper

YCC is created to compress the bitrate of the video. Because the human eye can see difference in light better then colours you separate them in to luma (Y) and chroma (C) channels and display the chroma channel in lower resolution.

4:4:4 is full resolution of both chroma and luma.
4:2:2 is full luma, full vertical chroma resolution, but only half horizontal chroma resolution.
4:2:0 is full luma and half chroma resolution.

Most videos are 4:2:0 to lower bitrate but the display have to upscale the signal to full resolution 4:4:4 to display it.

Yes, but why do these modes exist if there is no source material in it?

[vivan]

Yet again - why not?
Also there is source material in it. E.g. screen capture. Or 2x downscaling.

[ThurstonX]

Originally Posted by Qaq

I have to set my TV's HDMI input to "PC" to get RGB input, but level is limited by default, so I change it to full by switching Black level from Low (16-235) to High (0-255).

That makes sense. I tried that with my TV, but most of the Advanced controls become inactive when the input is set to "PC". I might have to play with that some more, since the Black Level setting is the key, and it is enabled. I need it set to Low with my current config.

Thanks for the reminder

[ThurstonX]

Originally Posted by Dodgexander

But those are RGB inputs, not YCbCr. I take it you meant in your earlier post you set CCC too Full RGB along with MadVR, because asfaik theres no way to get Mad Vr to accept YCbCr.

I'm not sure I follow. Your original question was:

"Whats the difference between setting YCbCr and RGB and which should be used with MadVR?"

as relates to the Pixel Color Format setting in CCC. You can have it set to YCbCr 4:4:4 and still get a picture using madVR, but it might not (probably won't?) look very good. That was my experience anyway, after updating the CCC + drivers. Sometimes AMD/ATI updates reset the Pixel Color Format, which is annoying.

I don't see a setting in madVR related to RGB levels OTHER THAN the setting I named. And that is how madVR outputs to the display device, unless I'm seriously confused (a distinct possibility).

So, where in madVR, other than that option, can I set some RGB option?

In LAV Video I have it set to "PC (0-255)" for "RGB Output levels (for YUV -> RGB conversion)".

[Dodgexander]

Originally Posted by ThurstonX

I'm not sure I follow. Your original question was:

"Whats the difference between setting YCbCr and RGB and which should be used with MadVR?"

as relates to the Pixel Color Format setting in CCC. You can have it set to YCbCr 4:4:4 and still get a picture using madVR, but it might not (probably won't?) look very good. That was my experience anyway, after updating the CCC + drivers. Sometimes AMD/ATI updates reset the Pixel Color Format, which is annoying.

I don't see a setting in madVR related to RGB levels OTHER THAN the setting I named. And that is how madVR outputs to the display device, unless I'm seriously confused (a distinct possibility).

So, where in madVR, other than that option, can I set some RGB option?

In LAV Video I have it set to "PC (0-255)" for "RGB Output levels (for YUV -> RGB conversion)".

Originally Posted by ThurstonX

Anecdotally, I can tell you the only way to get a decent pic on my LED LCD TV is to have Catalyst Control Center set to Full RGB. I then tell madVR that my display expects YCbCr.

When you mentioned setting madVR to expect YCbCr, you meant just the video levels of 0-255? There isn't a way to tell MadVR to use YCbCr over RGB, which is why your post confused me, I was wondering if I was missing something!

Originally Posted by vivan

Yet again - why not?
Also there is source material in it. E.g. screen capture. Or 2x downscaling.

What I mean is, why are these options there on a PS3 or Blu Ray player for example?

Why have extra colour spaces when theres no source material to take advantage of it. For a PC I understand why this conversion takes place, but why on a PS3 or Blu Ray player?

I thought "deep colour" and "extra white and black" was a feature of HD and that it would be utilized when playing back a BRD. So it turns out the Colour is just the same quality as DVD??

[Heuer]

Originally Posted by 6233638

Do you have the "delay playback start until render queue is full" option disabled? 701 dropped frames is a lot.
I just get a single repeated frame on the stats when I start playback.

Yes it is disabled. With it enabled dropped frames drops to ~60 and stays there.

[ThurstonX]

Originally Posted by Dodgexander

When you mentioned setting madVR to expect YCbCr, you meant just the video levels of 0-255? There isn't a way to tell MadVR to use YCbCr over RGB, which is why your post confused me, I was wondering if I was missing something!

That's why I was very specific about what option to which I was referring If I understand the option, it's telling madVR what level of RGB the display expects. So, nothing to do with what is being sent to madVR. And since madVR is the renderer, it's getting the signal from the decoder, yes? So if, e.g., LAV Video is set to "RGB Output levels PC (0-255)," then that's what madVR is getting.

Originally Posted by Dodgexander

What I mean is, why are these options there on a PS3 or Blu Ray player for example?

Why have extra colour spaces when theres no source material to take advantage of it. For a PC I understand why this conversion takes place, but why on a PS3 or Blu Ray player?

I thought "deep colour" and "extra white and black" was a feature of HD and that it would be utilized when playing back a BRD. So it turns out the Colour is just the same quality as DVD??

re: why are those options available in players, I think that "Choosing a Color Space" article (thanks! btw; an excellent read for newbs like me) explains it pretty well in "The Conversion Chain" section.

"First the video needs to be converted from 4:2:0 to 4:2:2, then to 4:4:4, then to RGB, and finally it can be fed to the display controller. This is the same process no matter what display technology is being used, whether LCD, DLP, plasma, or CRT." ...

...and on from there. So, if I understand that section correctly, 4:4:4 (or even RGB?) from the player *may* be better than having the display do the conversion. And from what others have said over the past day or so, displays aren't so great at that.

So am I correct if I say...
if one sets their video card to the Pixel Color Format (AMD name) RGB 4:4:4 (Full RGB), the card is doing the conversion and outputting the converted signal to the display, and the display is not doing any conversion.

In the end, I thought this paragraph summed it up pretty well:

"Unfortunately device makers tend not to reveal the exact processing steps they use internally, or the algorithms they use to convert various color spaces to RGB. Some use different algorithms depending on which color space is fed in. The bottom line is to assume nothing, and test every combination."

So I tested and settled on what looks best. Setting my TV's HDMI input to the "PC" label disables too many options (ratios, as well as Advanced stuff), and I couldn't see a difference, at least when watching US cable TV.

Sorry if this is hijacking the thread. Thanks for indulging. I'll shutup now

[6233638]

Originally Posted by nevcairiel

My Sony TV has a mode that allows full 4:4:4 with RGB, and seems to pass all the tests people made up for 4:4:4 support, however it disables its 24p cinema processing then (which makes the video smoother without the "artificial" feel of full interpolation), and i rather have that.
With video content, 4:2:2 is already much better then 4:2:0, and even if i loose some detail in chroma again, its not *that* obvious, while losing the 24p cinema mode is quite obvious (to me - which is what counts )

My Sony LCD is the same - in the Game or Graphics scene mode, it displays RGB or 4:4:4 YCC at full resolution, but in all other modes that is lowered to 4:2:2.

The game/graphics modes still display 24p correctly, but disable MotionFlow interpolation (which is very good at reducing judder but not introducing a sped-up look) and put the set into a lower contrast mode that is optimized for latency rather than image quality.

The local dimming no longer turns backlight zones off, and drops contrast to about 3,500:1. To improve latency, it also decouples the backlight array from the LCD panel, with about a frame of latency between them. This is not really a problem at only 3,500:1 contrast, but would have been if it allowed the local dimming zones to be turned off, as it does in the Theater mode.


That said, the benefits of madVR are still visible when the set processes in 4:2:2, and you can still tell the difference between a good and bad chroma scaling algorithm (e.g. aliasing, loss of saturation) but it's certainly not as obvious as it is in the Game/Graphics modes. (where I do all my testing/evaluation)

Originally Posted by Dodgexander

Yes, but why do these modes exist if there is no source material in it?

Because displays themselves are made up of RGB subpixels, and are a 4:4:4 display. (technically 4:4:4 refers to YCC though) There are clear benefits when using good chroma upsampling to go from 4:2:0 to RGB with madVR.

And PC sources are all RGB native, as are console games.

Originally Posted by Dodgexander

I thought "deep colour" and "extra white and black" was a feature of HD and that it would be utilized when playing back a BRD. So it turns out the Colour is just the same quality as DVD??

4:2:0 means that the Chroma ("color") channel is 1/4 the resolution of the Luma channel.

With Blu-ray that means a 1920x1080 Luma channel, with a 960x540 Chroma channel.
With DVD you have a 720x480 Luma channel and a 360x240 Chroma channel. (or 720x576 and 360x288 if it's PAL)

So both being encoded using 4:2:0 does not make them "the same".

Originally Posted by ThurstonX

So am I correct if I say...
if one sets their video card to the Pixel Color Format (AMD name) RGB 4:4:4 (Full RGB), the card is doing the conversion and outputting the converted signal to the display, and the display is not doing any conversion.

madVR converts from 4:2:0 YCC to RGB with high precision.

Computers render natively in 0-255 RGB. So by setting your video card to output 0-255 "Full" RGB you avoid any further conversions in your PC.

If your output is Full/Limited YCC, or Limited 16-235 RGB, then the video card is performing a conversion on the output - and in most cases, that should be avoided, as video cards typically do not do it with enough precision.


Once it ends up at your display, you have no idea what it is doing with the image really. But typically displays will be using more internal precision than your video card does when performing these conversions, and there's nothing you can do about it anyway.

What seems to happen these days, is that most displays convert everything to 4:2:2 YCC internally for processing (grayscale, gamma, CMS etc) which then must end up as RGB because pretty much all displays are made up of RGB subpixels.

[Qaq]

Originally Posted by 6233638

That said, the benefits of madVR are still visible when the set processes in 4:2:2, and you can still tell the difference between a good and bad chroma scaling algorithm (e.g. aliasing, loss of saturation) but it's certainly not as obvious as it is in the Game/Graphics modes. (where I do all my testing/evaluation).
.......
What seems to happen these days, is that most displays convert everything to 4:2:2 YCC internally for processing (grayscale, gamma, CMS etc) which then must end up as RGB because pretty much all displays are made up of RGB subpixels.

Thanks, interesting. Being madVR's user would you buy a 4:2:2 TV (no 4:4:4 RGB at all)?

[6233638]

Originally Posted by Qaq

Thanks, interesting. Being madVR's user would you buy a 4:2:2 TV (no 4:4:4 RGB at all)?

If you are only using it for video, 4:2:2 is fine - especially at the distances that most people sit to watch TV.

It does negate some of the benefits of madVR, but doesn't eliminate them.

If you have plans on using a PC hooked up to the display for other reasons though (e.g. browsing the web, gaming) or connecting up video games consoles, I would not want a display that can't display RGB at full resolution, because those sources are RGB native.


I tried taking some photographs to illustrate the differences between various scaling algorithms when displayed at 4:2:2 and 4:4:4, but unfortunately they don't show it as clearly as I had hoped. What I did find though, was that with my TV operating at 4:2:2 - at least with the sample that I tried - there is zero difference between Jinc 3 AR and Lanczos 3 AR Chroma. They're not just "very close" or "similar" - I can layer the images on top of each other in Photoshop and use the "difference" layer blending tool, and nothing shows up.

4:2:2 chroma really does seem to serve as an "equalizer" and remove a lot of the differences between algorithms. But you can still tell the difference between a soft chroma algorithm and a sharp one. It's more difficult to see differences in aliasing though.

Comparing Nearest Neighbor scaling probably shows off the differences between 4:2:2 and 4:4:4 the clearest - it removes a lot of the aliasing. (it's still visible in person - the photo makes it look like it just disappeared)


But that's not a good thing - that shows just how much is being thrown away with 4:2:2, and how much it's blurring chroma as a result.

I already mentioned that it makes Jinc 3 AR and Lanczos 3 AR look identical, making Jinc pointless for chroma if your set only displays 4:2:2. I wish I had though to test it, but I suspect that there would be no difference between Bicubic 75 AR and Lanczos 3 AR either, even though there are clear differences between the three of those at 4:4:4.

When you look closer at Jinc in 4:4:4 vs Jinc in 4:2:2 for example, you notice that it is not as sharp, edges look fuzzy, and the finer lines are not as bright. If you look at the left of the A here, you see that it is not uniformly lit at 4:2:2


These things are much easier to see on the display itself rather than these photographs though.


Keep in mind that only chroma scaling is affected - luma scaling should be no different in 4:2:2 or 4:4:4, and that is going to be much more noticeable than chroma scaling anyway.


I think this is good news though - it shows that upscaling chroma to 4:4:4/RGB with madVR does indeed make sense.

I've seen many people argue that there's no point for a television to display full 4:4:4/RGB resolution at all because video sources are 4:2:0 native anyway - well this clearly shows that there is a benefit to it.

That's not to say it's a massive difference and that you should avoid buying a display if it won't pass full RGB resolution, but it's nice to know that it can make a difference.