Thread: Zopti
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Old 6th February 2019, 03:17   #19  |  Link
WorBry
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Join Date: Jan 2004
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Quote:
Originally Posted by Boulder View Post
.. so it looks like VMAF cannot measure the difference between the clips accurately enough.
There's also this issue where the VMAF result is skewed by a component 'motion2=0' score for the first frame in a clip:

https://forum.doom9.org/showthread.p...61#post1864561

The only information I can find about this parameter is:

"Motion. This is a simple measure of the temporal difference between adjacent frames. This is accomplished by calculating the average absolute pixel difference for the luminance component."

https://medium.com/netflix-techblog/...c-653f208b9652

and:

"motion2 score typically ranges from 0 (static) to 20 (high-motion)"

https://github.com/Netflix/vmaf/blob...hon_library.md

Testing your Blacksails clip against itself, with VapourSynth VMAF v3 (Model=0) gives:

Code:
<params model="" scaledWidth="1920" scaledHeight="1080" subsample="1" num_bootstrap_models="0" bootstrap_model_list_str="" />
<fyi numOfFrames="8" aggregateVMAF="99.6711" aggregatePSNR="60" aggregateSSIM="0.99993" aggregateMS_SSIM="0.999936" execFps="2.27555" timeTaken="3.51563" />
<frames>
<frame frameNum="0" adm2="1" motion2="0" ms_ssim="0.999889" psnr="60" ssim="0.9999" vif_scale0="0.999999" vif_scale1="0.999997" vif_scale2="0.999995" vif_scale3="0.999995" vmaf="97.4274" />
<frame frameNum="1" adm2="1" motion2="51.9751" ms_ssim="0.999997" psnr="60" ssim="0.999997" vif_scale0="0.999999" vif_scale1="0.999998" vif_scale2="0.999997" vif_scale3="0.999997" vmaf="100" />
<frame frameNum="2" adm2="1" motion2="45.4778" ms_ssim="0.999998" psnr="60" ssim="0.999999" vif_scale0="0.999999" vif_scale1="0.999998" vif_scale2="0.999996" vif_scale3="0.999998" vmaf="100" />
<frame frameNum="3" adm2="1" motion2="45.4778" ms_ssim="0.999994" psnr="60" ssim="0.999995" vif_scale0="0.999997" vif_scale1="0.999994" vif_scale2="0.999994" vif_scale3="0.999994" vmaf="100" />
<frame frameNum="4" adm2="1" motion2="48.0867" ms_ssim="0.99986" psnr="60" ssim="0.999837" vif_scale0="0.999999" vif_scale1="0.999996" vif_scale2="0.999995" vif_scale3="0.999995" vmaf="100" />
<frame frameNum="5" adm2="1" motion2="71.4518" ms_ssim="0.999999" psnr="60" ssim="0.999999" vif_scale0="1" vif_scale1="0.999999" vif_scale2="0.999998" vif_scale3="0.999998" vmaf="100" />
<frame frameNum="6" adm2="1" motion2="74.8847" ms_ssim="0.999751" psnr="60" ssim="0.999716" vif_scale0="0.999994" vif_scale1="0.999994" vif_scale2="0.999994" vif_scale3="0.999994" vmaf="100" />
<frame frameNum="7" adm2="1" motion2="74.8847" ms_ssim="1" psnr="60" ssim="1" vif_scale0="0.999998" vif_scale1="0.999995" vif_scale2="0.999993" vif_scale3="0.999994" vmaf="100" />

FFMPEG SSIM reports lossless, 1.00000 (Inf)
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Last edited by WorBry; 6th February 2019 at 03:28.
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