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Old 30th March 2020, 05:59   #26  |  Link
poisondeathray
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Join Date: Sep 2007
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Quote:
Originally Posted by Stereodude View Post
2) You have to also use z.lib explicitly set to full range, the matrix and transfer coefficients seem to have no effect, but the range certainly does.
Nice, that fixes the earlier observations about low Y PSNR values for avsresize/zimg for that conversion.

My thinking was input=output so it's a no-op, so I omitted the args. Lesson learned!

Quote:
I also found that if you're using the internal avisynth functions converting to 8 bit first then to YV12 gives a slightly better PNSR score.
Interesting. You'd think higher precision @ 10bit operations would produce slightly better results

Quote:
I was not able to find a matrix for the internal function that gave similar results.
Matrix only applies to YUV<=>RGB transforms , so it's not applicable here. That I'm sure of for the internal functions. (I'm questioning my understanding of how avsresize works.)



My results using the clip in avsresize/zimg. Not sure if it was the same clip because it was 5002 frames vs 5000. And the trends seem different w.r.t the frame ranges . My U plane seemed more problematic than V , but your V seemed to have more trouble than your U . Values seem slightly higher too , the min was 56.288 in vqmt , but you have clear V drops below 50
https://postimg.cc/QHcjV8V7

VQMT scales the U,V planes to Y plane size, that might introduce some errors. I tried unchecking that option , but it would crash. It might be a pro version feature. Anyways it's the trends that are important

FWIW this is ffmpeg PSNR , and the abs. min value is higher , and the U,V averages are higher than VQMT - maybe some of the difference is from the VQMT UV scaling, not sure. Often there are slightly different calcs too between programs
PSNR y:65.979368 u:64.950274 v:66.120163 average:65.812176 min:59.375502 max:88.556475

You can combine methods too. If a different method produces higher values in a plane you mix/match with combineplanes. But like you said this is splitting hairs these higher PSNR values. It just sucks to see drops like that in sections
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