madVR - high quality video renderer (GPU assisted)

[madshi]

Originally Posted by ryrynz

Jinc AR looks similar to Catmull-Rom with 4K to 1080, it's a little more natural I feel, it's a good downscaler it just suffers from the same softening effect that SSIM overcomes.

Then probably SSIM 2D is the right one for you. It's more or less a combination of Jinc + SSIM.

Originally Posted by ryrynz

Is linear light recommended with downscaling generally? It certainly pumps up whites, I notice black text on white backgrounds seems to suffer some fading.. probably a bit hit and miss.

It should produce the most accurate results, so I generally recommend turning it on.

-------

nevcairiel just released a new nightly LAV build with:

Direct Blu-Ray 3D playback support

Currently limited to only support playing SSIF files directly. See his post here:

http://forum.doom9.org/showthread.ph...66#post1757466

[aufkrawall]

Originally Posted by ryrynz

Look at the ends of the crates..

True, but they often look too aliased to me with SSIM.
I feel the same regarding the windmill picture, looks like every pixel is to represent a different brick or so.

[FDisk80]

Originally Posted by madshi

Then probably SSIM 2D is the right one for you. It's more or less a combination of Jinc + SSIM.


It should produce the most accurate results, so I generally recommend turning it on.

-------

nevcairiel just released a new nightly LAV build with:

Direct Blu-Ray 3D playback support

Currently limited to only support playing SSIF files directly. See his post here:

http://forum.doom9.org/showthread.ph...66#post1757466

[leeperry]

Originally Posted by madshi

I've linked the original image. Look at it in original resolution and then look again at the downscaled images. Bicubic drops a lot of details which are visible in the SSIM image. SSIM is not a simple sharpener. It measures the detail level in the original image and tries to reproduce it properly (for human perception) in the downscaled image. SSIM is supposed to reproduce exactly the image we would see with our eyes, if we just put some distance between us and the object we're looking at. Of course SSIM is limited by the number of pixels and the aliasing the lower number is causing. But other than that, the sharpness produced by SSIM should be fairly accurate.

I've always been rather unhappy with how soft downscaled images got and thought they should really look sharper.

Fair enough but even your original image seen as 1:1 on a 1080p display has been very obviously sharpened, again windmills and boats in Holland don't look all that plasticky and edge enhanced.

A more valid comparison would be using a natural looking picture and see whether it still looks natural and detailed after being downscaled but I just spent 15 mins on google and it's pretty hard to find a pristine looking 4K picture.....mostly because it would appear that the higher you crank the megapixels count the noisier sensors inevitably get to some extent(much like audio that mostly captures stray noise >88.2kHz from what Dan Lavry said) and even the nerdiests who go RAW and postprocess in pshop sadly don't have mVR at their disposal. It's rather unfunny how picture viewers/editors look terribly dated compared to mVR. Would need to use 4K demos screenshots I think.

[kasper93]

Originally Posted by madshi

Ah, I see. SSIM currently requires both X and Y to be downscaled (or at least not upscaled). In your case one direction needs upscaling, the other downscaling. In that case SSIM doesn't work. Well, I suppose I could force image doubling in such a way that both X and Y are doubled the same number of times so that SSIM can be used afterwards. But to be honest, I don't think for downscaling after doubling SSIM has much benefit over Bicubic150.

I see. One more question, why super-xbr always scale X and Y the same? Is it limitation? https://www.dropbox.com/s/mhtb9wguc7nrfdm/xbr.png

[madshi]

Originally Posted by leeperry

Fair enough but even your original image seen as 1:1 on a 1080p display has been very obviously sharpened, again windmills and boats in Holland don't look all that plasticky and edge enhanced.

A more valid comparison would be using a natural looking picture and see whether it still looks natural and detailed after being downscaled but I just spent 15 mins on google and it's pretty hard to find a pristine looking 4K picture.....mostly because it would appear that the higher you crank the megapixels count the noisier sensors inevitably get to some extent(much like audio that mostly captures stray noise >88.2kHz from what Dan Lavry said) and even the nerdiests who go RAW and postprocess in pshop sadly don't have mVR at their disposal. It's rather unfunny how picture viewers/editors look terribly dated compared to mVR. Would need to use 4K demos screenshots I think.

One good test is to see what happens if you use PiP for live TV. Here's a comparison using DVBViewer:



(original frame)

Now are you really telling me that SSIM is too sharp and detailed, and that Catmull-Rom is the only way to get a natural looking downscale? To my eyes the Catmull-Rom image looks like I forgot to put my glasses on (if I had any).

Originally Posted by kasper93

I see. One more question, why super-xbr always scale X and Y the same? Is it limitation? https://www.dropbox.com/s/mhtb9wguc7nrfdm/xbr.png

The algorithm by design always doubles both X and Y resolution. The algorithm simply can't scale only one direction. It's technically impossible, due to the way the pixels are interpolated.

[kasper93]

Thanks. I once might look into those algorithms to see what's going on

[KoD]

Thanks madshi, downscaling of vobsubs/sups works fine now.

[leeperry]

Originally Posted by madshi

Now are you really telling me that SSIM is too sharp and detailed, and that Catmull-Rom is the only way to get a natural looking downscale?

It's all about compromises, Bicubic50 is very obviously too soft for such a drastic downscale and SSIM has way too little pixels headroom to output anything but an overprocessed looking picture. I have yet to play around with the 1D/2D SSIM sub-options but an overprocessed looking über-sharp 1080p picture is not on my agenda, great news if it works wonders on PIP and 4K

I'll try to find a pristine looking 4K picture and come back with 1080p comparisons.

[JarrettH]

PIP isn't supposed to look good

[Stereodude]

FWIW, SSIM 1D & 2D gave me very nice results with the one UHD test clip I used on my 1080p plasma. Is it too sharp? I have no idea. SSIM 2D seemed even sharper than 1D. Jinc downscaling didn't seem much sharper than Catmull-rom. Granted I don't anticipate having much UHD content to play back so the discussion is mainly academic at this point to me.

Originally Posted by Stereodude

FWIW, SSIM 1D & 2D gave me very nice results with the one UHD test clip I used on my 1080p plasma. Is it too sharp? I have no idea. SSIM 2D seemed even sharper than 1D. Jinc downscaling didn't seem much sharper than Catmull-rom. Granted I don't anticipate having much UHD content to play back so the discussion is mainly academic at this point to me.

But downscaling isn't applied only when you play video files with resolutions above 1080p, assuming that your native display resolution is 1080p.

AFAIK, Downscaling also gets applied if you utilize Image Doubling/Multiplying for sub-1080p content. For example, 720p content with doubling will result in downscaling on 1080p display because 720x2 (doubling) or 720x4 (quadrupling) will result in image resolutions above 1080p (1440p when doubled or 2880 when quadrupled), thus requiring downscaling back to 1080p.

Why is madVR using the term "Image Doubling" for a section that includes doubling, quadrupling, and even "octupling"? Why not just use "Image Multiplication" or "Image 2x/4x/8x Multiplication" ??? "Image Doubling" doesn't sound very accurate...

[Thunderbolt8]

Originally Posted by madshi

I've always been rather unhappy with how soft downscaled images got and thought they should really look sharper.

I think the point is that you aim for the scaler to output that image which resembles the source most accurately, while leeperry wants an accurate image as well (to his liking), but just at the very end of the process when the image hits the screen and not necessarily after only scaling. so for you its only 1 step to arrive at this target, while for him it can be many steps with additional sharpening after scaling etc. thats where you disagree with each other. so SSIM might shoot too far off target with its sharpening, but it still resembles the source image more closely than the other algorithms. leeperry is willing to use more than one step to arrive at this target and therefore can go with an algorithm that wont sharp too much to be save and then can apply more sharpening more presicely afterwards to resemble the original image better (or maybe just better for his own liking).

bottom line is I guess you have to decide for yourself if you want everyone to go with the 1 step solution (or at least be more limited in your options compared to what leeperry wants) or leave room in case others want additional tweaking.

[Stereodude]

Originally Posted by XMonarchY

But downscaling isn't applied only when you play video files with resolutions above 1080p, assuming that your native display resolution is 1080p.

Yes, that depends on your settings.

AFAIK, Downscaling also gets applied if you utilize Image Doubling/Multiplying for sub-1080p content. For example, 720p content with doubling will result in downscaling on 1080p display because 720x2 (doubling) or 720x4 (quadrupling) will result in image resolutions above 1080p (1440p when doubled or 2880 when quadrupled), thus requiring downscaling back to 1080p.

I image double DVDs with NNEDI3 and then upscale them the rest of the way with Jinc AR. I did not find quadrupling to work satisfactorily previously in my experimentation when NNEDI3 was the only doubling option.

I can image double 720p24 and then scale it down to 1080p, but 720p60 was a no go last time I tried it. I've since gotten a PCIe 3.0 motherboard, gone all x64, and now there are more possible doubling routines so maybe I should revisit. However, with the previous options and the fact I didn't have any source of 720p24 content (it's not on Blu-rays or broadcast/OTA HDTV) downscaling after doubling was not common for me.

I guess that leads to an interesting question in the case of 720p -> 1080p. Is image doubling with a super -xbr flavor and then downscaling with one of these new sharper routines preferable to straight Jinc AR upscaling? I'll have to test the render times for this later when I get home.

[ryrynz]

Originally Posted by leeperry

I'll try to find a pristine looking 4K picture and come back with 1080p comparisons.

Well with that 50Mbps 4K Chimei inn video which is pretty pristine it's obviously how much better SSIM does with fine details. Things like hair and fabric patterns, small leaves, jewelry etc. It's no contest when it comes to real life content.

Originally Posted by Stereodude

FWIW, SSIM 1D & 2D gave me very nice results with the one UHD test clip I used on my 1080p plasma. Is it too sharp? I have no idea. SSIM 2D seemed even sharper than 1D..

It's not though.

[Stereodude]

Originally Posted by ryrynz

It's not though.

It's not too sharp or 2D isn't sharper than 1D SSIM?

The edges of fine text were definitely crisper with 2D than 1D.

[dansrfe]

Crash on v0.90.10:

https://drive.google.com/file/d/0B9i...0FIeV80OWxjTlU

[ryrynz]

Originally Posted by Stereodude

It's not too sharp or 2D isn't sharper than 1D SSIM?

The edges of fine text were definitely crisper with 2D than 1D.

Both.

No, the edges are better defined.. not sharper. It's more accurate to the source. If anything it should look slightly less sharp due to the absence of some ringing that 1D has, but it's hard to notice.

[Warner306]

Originally Posted by XMonarchY

Why is madVR using the term "Image Doubling" for a section that includes doubling, quadrupling, and even "octupling"? Why not just use "Image Multiplication" or "Image 2x/4x/8x Multiplication" ??? "Image Doubling" doesn't sound very accurate...

I think image doubling is accurate. A 4x resize is still a double -- it is a double of a double. Every resize is a multiple of 2x; therefore, it is a double.