ColorMatrix for Vapoursynth - Page 2

Myrsloik · 19th October 2012, 18:07

I also call bullshit on this one. I have a calibrated ips screen and even after minutes of staring both pictures look identical.

kolak · 19th October 2012, 19:29

For me to bottom one is bit darker/more saturated, specially in the top/left quarter (and on reds).

Funny enough I did load it to photoshop and thought that there is no difference, but difference mode shows difference, exatctly in places which I described

I think it was more imaginary and due to LCD angels, even if I have very good monitor, but I'm also convince that I did see "real" difference

19th October 2012, 19:39

No, it's not. You are imaging a difference that does not exist. The pictures are basically identical beyond the value difference in the YUV planes being .01 between them. Here is the two images run through Histogram. If there was a brightness or saturation difference the graphs would not be almost exactly the same.

To add further this is the output from changing them with only Tweak(sat=1.1,bright=.9). It's hardly a dramatic change yet you can see the YUV graphs are noticeably different.

kolak · 19th October 2012, 19:52

Yes they are almost identical- basically identical, but funny enough difference is in areas which I did described, before I checked it in Photoshop. Probably simple coincidence.
I think it's due to monitor angles imperfection.

19th October 2012, 19:54

Yes, as I said on the previous page you get basically a perfect gray image by subtracting them. So, in conclusion, while the doc did have a warning that there will potentially be mathematically different values between the C and SSE2 routines, it is hardly what is going to be perceptible.

kolak · 19th October 2012, 19:59

I would imagine that difference at this level is not a problem at all.

ajp_anton · 19th October 2012, 23:07

If you're looking at them side by side, your conclusion means nothing because, as you said, the monitor's angle differences will be much larger anyway.
I also have a high quality screen, and I can't spot a difference even if I flip back and forth between them in different tabs.

jmac698 · 22nd October 2012, 21:44

http://www.screenshotcomparison.com/comparison/153403

I admit I can't see a difference.

ryrynz · 25th October 2012, 00:38

It'll likely be the viewing angle properties of his LCD screen affecting the contrast of the bottom image more as he's not doing a proper comparison in an image viewer and instead looking at them as they're presented on the forum.

jackoneill · 11th November 2012, 10:44

Hello.

Could you share that ported assembly code, please?

Or... nevermind now, I guess.

19th October 2012, 18:07	#21 \| Link
Myrsloik Professional Code Monkey Join Date: Jun 2003 Location: Kinnarps Chair Posts: 2,647	I also call bullshit on this one. I have a calibrated ips screen and even after minutes of staring both pictures look identical. __________________ VapourSynth - proving that scripting languages and video processing isn't dead yet

19th October 2012, 19:29	#22 \| Link
kolak Registered User Join Date: Nov 2004 Location: Poland Posts: 2,869	For me to bottom one is bit darker/more saturated, specially in the top/left quarter (and on reds). Funny enough I did load it to photoshop and thought that there is no difference, but difference mode shows difference, exatctly in places which I described I think it was more imaginary and due to LCD angels, even if I have very good monitor, but I'm also convince that I did see "real" difference Last edited by kolak; 19th October 2012 at 19:38.

19th October 2012, 19:39	#23 \| Link
SassBot Guest Posts: n/a	No, it's not. You are imaging a difference that does not exist. The pictures are basically identical beyond the value difference in the YUV planes being .01 between them. Here is the two images run through Histogram. If there was a brightness or saturation difference the graphs would not be almost exactly the same. To add further this is the output from changing them with only Tweak(sat=1.1,bright=.9). It's hardly a dramatic change yet you can see the YUV graphs are noticeably different. Last edited by SassBot; 19th October 2012 at 19:49.

11th November 2012, 10:44	#30 \| Link
jackoneill unsigned int Join Date: Oct 2012 Location: 🇪🇺 Posts: 760	Hello. Could you share that ported assembly code, please? Or... nevermind now, I guess. __________________ Buy me a "coffee" and/or hire me to write code! Last edited by jackoneill; 16th November 2012 at 15:38.

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19th October 2012, 19:52	#24 \| Link
kolak Registered User Join Date: Nov 2004 Location: Poland Posts: 2,869	Yes they are almost identical- basically identical, but funny enough difference is in areas which I did described, before I checked it in Photoshop. Probably simple coincidence. I think it's due to monitor angles imperfection.

19th October 2012, 19:54	#25 \| Link
SassBot Guest Posts: n/a	Yes, as I said on the previous page you get basically a perfect gray image by subtracting them. So, in conclusion, while the doc did have a warning that there will potentially be mathematically different values between the C and SSE2 routines, it is hardly what is going to be perceptible.

19th October 2012, 19:59	#26 \| Link
kolak Registered User Join Date: Nov 2004 Location: Poland Posts: 2,869	I would imagine that difference at this level is not a problem at all.

19th October 2012, 23:07	#27 \| Link
ajp_anton Registered User Join Date: Aug 2006 Location: Stockholm/Helsinki Posts: 807	If you're looking at them side by side, your conclusion means nothing because, as you said, the monitor's angle differences will be much larger anyway. I also have a high quality screen, and I can't spot a difference even if I flip back and forth between them in different tabs.

22nd October 2012, 21:44	#28 \| Link
jmac698 Registered User Join Date: Jan 2006 Posts: 1,869	http://www.screenshotcomparison.com/comparison/153403 I admit I can't see a difference.

25th October 2012, 00:38	#29 \| Link
ryrynz Registered User Join Date: Mar 2009 Posts: 3,697	It'll likely be the viewing angle properties of his LCD screen affecting the contrast of the bottom image more as he's not doing a proper comparison in an image viewer and instead looking at them as they're presented on the forum.