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[HELP] Change the Default Sharpening Value of CAS from 0.6 when using stepped resize - Printable Version

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RE: Change the Default Sharpening Value of CAS from 0.6 when using stepped resize - Selur - 21.12.2023

Are these 'vertical line like blocking artifacts' visible in the Vapoursynth Preview?
Can you share a short sample of a clip before reencoding which get these artifacts after filtering and reencoding and also share your filtering and reencoding settings?
(without actually seeing and be able to reproduce the problem, it's hard to suggest anything)

wild guesses, assuming those artifacts are not visible in the Vapoursynth Preview and thus are caused by the reencoding:
(I also assume you use a high enough bit rate / low enough quantizer to keep those details)
a. make sure to use 10bit encoding
b. since this only happens in grainy areas, try using 'tune grain' or some of its settings
--aq-mode 0
        --cutree 0
        --ipratio 1.1
        --pbratio 1.0
        --qpstep 1
        --sao 0
        --psy-rd 4.0
        --psy-rdoq 10.0
        --recursion-skip 0
source: https://x265.readthedocs.io/en/master/presets.html#film-grain
This will increase the required bit rate for the same quality, but will try to keep more grain.

=> to give better help, I would need a way to reproduce this.

Cu Selur

Ps.: Nowadays, I would not recommend to use -3/-3, but at most -1/-1.

RE: Change the Default Sharpening Value of CAS from 0.6 when using stepped resize - buzzter - 19.01.2024

Hi !
No, The Artifacts are not visible in vapoursynth preview. It has to do with encoding settings i guess. Even with crf 16 on no-hdr videos and crf  11-14 on hdr10. It is difficult to spot on smaller monitors but apparent on  55 inch TVs.  
I wish deblock -1,-1 works but it simply leaves out fine details. -2, -2 is usable but it produces deblocking artifacts almost close to -3,-3.


For now, Managing with the following settings:
--preset slow  --output-depth 10 --y4m --profile main10 --subme 5 --bframes 10 --rc-lookahead 120 --crf 16.00 --psy-rd 2.00  --psy-rdoq 1.00 --deblock=-3:-3  --no-sao --aq-mode 3 --aq-strength 0.8 --strong-intra-smoothing  --rskip 0 --no-open-gop --no-cutree --ref 6

usually reproduces 1080p video at 14000 - 20000 kbps bitrate with minimal artifacts.
i'll have to try aq-mode 0 and 1 .

keeping the details, and eliminating the artifacts while keeping the bitrate sane seems to be challenging.

RE: Change the Default Sharpening Value of CAS from 0.6 when using stepped resize - Selur - 19.01.2024

Quote:The Artifacts are not visible in vapoursynth preview.
okay, that at least throws Vapoursynth problems out and points to encoding settings.

--preset slow  --output-depth 10 --y4m --profile main10 --subme 5 --bframes 10 --rc-lookahead 120 --crf 16.00 --psy-rd 2.00  --psy-rdoq 1.00 --deblock=-3:-3  --no-sao --aq-mode 3 --aq-strength 0.8 --strong-intra-smoothing  --rskip 0 --no-open-gop --no-cutree --ref 6
Disabling soa and lowering the inloop-deblocking that much feels wrong, try using "-nr-intra X00 --nr-inter X00"
If you can share a small sample or your source and your other settings, I can try to reproduce and may be help with the settings.
Different aq modes might help too.

Cu Selur