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Old 1st March 2019, 23:50   #73  |  Link
poisondeathray
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Join Date: Sep 2007
Posts: 5,346
Quote:
Originally Posted by Iron_Mike View Post
is this for the VS flavor or for VMAF in general... where did you get this list ?
vapoursynth vmaf,

https://github.com/HomeOfVapourSynth...ourSynth-VMAF/


Quote:
since I wasn't sure whether the bitrate was an issue (for the VMAF calculation), I converted the main and ref clips to yuv444p (8bit) before passing them into ffmpeg libvmaf (by specifying the -pix_fmt)... ffmpeg VMAF will tell the format it uses to compare in the console output, for my main/ref clips (16bit/12bit) it defaults to yuv444p10le, but once u pass clips in as 8bit it uses that format...

the VMAF score whether using original bit depth, 12 bit, 10 or or 8bit for the main/ref clips was always ~ 96.x (real test, not control)
VMAF is probably less picky about those sorts of things, but it makes a significant difference on other metrics. There are a bunch of uncontrolled variables and operations there can cause wildly different results with other metrics - how it's scaled, dithering algo, etc...





Quote:
well, or in other words:
those results could easily be interpreted that from a certain CRF on, the encode is perceptually identical, which is the whole point of VMAF...

their samples are based on humans reporting perceived quality differences...
Yes , that's a good way of phrasing it

I personally haven't used VMAF enough to be comfortable with it yet

I personally don't find that particularly useful. I guess it might be good enough for "joe public" , they might not be able to tell the difference. But you can bet people that deal frequently with encoding, codecs, compression ; ie. people that post here - they can tell the difference between say, a crf 10 vs. crf 18 encode.

Maybe a conspiracy theory, but it's almost like a Netflix scheme trying to justify their low delivery bitrate practices

Last edited by poisondeathray; 2nd March 2019 at 00:02.
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