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Old 7th February 2019, 07:52   #50  |  Link
WorBry
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Quote:
Originally Posted by WorBry View Post
Actually, looking at the per-frame scores in that same log, it is just the VMAF score for the first frame that skews the aggregate result, and it looks like it's the motion2 metric (which measures temporal difference) score of 0 that is responsible for that. All of the remaining 499 frames have a VMAF score of 100.



To enlarge open image and click (+) cursor.

Perhaps there should be an option to exclude the first frame from the aggregate scores?
There again, that's not always the case. Here, the original 2160/50p Crowd Run (8bit 420, y4m) reference clip encoded to x264 CRF=0 (i.e. lossless with switch to qp 0 and High 444 Predictive profile), and the clips compared with VMAF v3 in Model=1 mode:

Code:
<VMAF version="1.3.11">
<params model="" scaledWidth="3840" scaledHeight="2160" subsample="1" num_bootstrap_models="0" bootstrap_model_list_str="" />
<fyi numOfFrames="500" aggregateVMAF="100" aggregatePSNR="60" aggregateSSIM="1" aggregateMS_SSIM="1"......
....
<frame frameNum="0" adm2="1" motion2="0" ms_ssim="1" psnr="60" ssim="1" vif_scale0="1" vif_scale1="0.999999" vif_scale2="0.999999" vif_scale3="0.999998" vmaf="100" />
<frame frameNum="1" adm2="1" motion2="8.42311" ms_ssim="1" psnr="60" ssim="1" vif_scale0="1" vif_scale1="0.999999" vif_scale2="0.999999" vif_scale3="0.999998" vmaf="100" />
So I guess you have to let it do it's thing and take the scores as they come.
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Last edited by WorBry; 7th February 2019 at 08:14.
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