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Old 8th March 2022, 17:24   #12  |  Link
benwaggoner
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Join Date: Jan 2006
Location: Portland, OR
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Quote:
Originally Posted by excellentswordfight View Post
Just a note here, although I also recommend specifying the level, level 5 doesnt support 2160p60 (which was mentioned in the first post).
Oops! Yeah, --level-idc 5.1 instead.

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It seems like Dave is mostly interested in tuning for compression, trying main10 is definitely something that might be worth pursuing even though it has a bit of an speed impact.
Main10 doesn't give much benefit at all over Main for 8-bit input and output in HEVC. It had a much bigger benefit in H.264.

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SAO has such a negatable speed impact that it is imo almost an irrelevant factor.
Yeah, quality is main reason for SAO on/off. At high bitrates, SAO can impair maximum detail. But at lower bitrates, SAO can suppress ringing and net improve visual quality.

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Whatever you think looks the best... Its normal that different aq-modes changes the bitrate at a given crf value.
A good reminder that it is often preferable to do psychovisual parameter tuning in 2-pass VBR mode, so one is comparing quality at a given average bitrate. Otherwise one winds up comparing different visual quality at different file sizes, which can be confounding.

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I also assume that compression is more important than seeking etc, so you can also set --keyint fps*10 --min-keyint fps. Using main10 is also something that you might wanna try as well (I personally only use main10 with x265, regardless of if the source is 8bit or not). As for all the other tuning that can be done... I'm gonna stay out of that, as it can be a rabit hole of pros & cons and can be dependent on a myriad of factors.
At 60 fps, that'd be a --keyint 600, which can make random access really slow. Compression efficiency is much more about the value of keyint itself (proxy for percentage of IDR frames). I'd probably start with --keyint 300 myself, for a maximum of a 5 second GOP
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