[Arhu]

Originally Posted by Asmodian

Adding --no-sao hurt quality and did not improve sharpness. This was not the case the last time I tested sao (probably about 6 months ago).

I only started testing with x265 2.5, don't know what it was before. I thought --no-sao made faces look dirty and prefer --sao.

As for the OP's question -- after lots of testing I came to the conclusion that I don't really like film grain. I don't like plastic faces either, however, so I'm trying to find a balance between the two for a more "natural" look. I also endlessly tried to decide which presets and settings I want to use, with no final result. After even more testing I decided to go for relatively simple presets.

1.
Apply slight digital noise reduction:

clip = core.fmtc.bitdepth(clip, bits=16)
clip = core.knlm.KNLMeansCL(clip, d = 4, s = 4, a = 4, h = 0.5)

Low values for h like 0.5 or 0.6 are usually good enough to mostly get rid of fine background noise in conjunction with x265's smoothing parameters (strong intra smoothing and sao). I also tried using BM3D and a refined combination of the two but it was just too slow.

2.
- Video parameters:
Bit depth: 10. Haven't experimented too much with 12.
Speed preset: Very slow (as others have already found out: at least Slow)
Custom parameters:

• -- aq-mode 3. I think this is necessary to get rid of artifacts in dark scenes that can appear even with CRF 16. It might be too strong by default and I tried with aq-strength 0.9 too, like others, but couldn't make up my mind.
• --sao (default). --no-sao made faces look dirty
• --strong-intra-smoothing (default). I think it's a must for CRF >= 20, but even for lower CRF values I thought the picture looked more accurate with this enabled.

- Audio parameters (Opus):

-mapping_family 1

... for 5.1+ encoding, to make sure the Opus library uses its multi-channel improvements from version 1.1. (At least in Staxrip 1.6 this needs to be set explicitly.)

3.
I use these quality presets as a guideline for video and audio. I also choose depending on how much I like a movie.
Note that these values are for noise reduced sources -- see step 1. Without the slight DNR I'd probably go 1 CRF higher for everything.

          Video                      Audio
 Q     ||  CRF  || Opus 2.0 | Opus 5.1 | Opus 6.1 | Opus 7.1  || Source Quality
-------++-------++----------+----------+----------+-----------++----------------
 Q0    ||  16   || 160 kbps | 400 kbps | 480 kbps | 560 kbps  || T0 Blu    movies (reference)
 Q0.5  ||  16.5 || 152 kbps | 380 kbps | 456 kbps | 532 kbps  || T0 Blu    movies (reference)
 Q1    ||  17   || 144 kbps | 360 kbps | 432 kbps | 504 kbps  || T1 Gold   movies
 Q1.25 ||  17.5 || 136 kbps | 340 kbps | 408 kbps | 476 kbps  || 
 Q1.5  ||  18   || 128 kbps | 320 kbps | 384 kbps | 448 kbps  ||
 Q1.75 ||  18.5 || 120 kbps | 300 kbps | 360 kbps | 420 kbps  || 
 Q2    ||  19   || 112 kbps | 280 kbps | 336 kbps | 392 kbps  || T2 Silver movies | T1 Gold series
 Q2.25 ||  19.5 || 104 kbps | 260 kbps | 312 kbps | 364 kbps  || 
 Q2.5  ||  20   ||  96 kbps | 240 kbps | 288 kbps | 336 kbps  ||
 Q2.75 ||  20.5 ||  88 kbps | 220 kbps | 264 kbps | 308 kbps  || 
 Q3    ||  21   ||  80 kbps | 200 kbps | 240 kbps | 280 kbps  || T3 Bronze movies | T2 Silver series
 Q3.25 ||  21.5 ||  76 kbps | 190 kbps | 228 kbps | 266 kbps  || 
 Q3.5  ||  22   ||  72 kbps | 180 kbps | 216 kbps | 252 kbps  ||
 Q3.75 ||  22.5 ||  68 kbps | 170 kbps | 204 kbps | 238 kbps  || 
 Q4    ||  23   ||  64 kbps | 160 kbps | 192 kbps | 224 kbps  || T4 Copper movies | T3 Bronze series
 Q4.5  ||  23.5 ||  60 kbps | 150 kbps | 180 kbps | 210 kbps  ||
 Q5    ||  24   ||  56 kbps | 140 kbps | 168 kbps | 196 kbps  || T5 Coal   movies | T4 Copper series

The tier ratings for movies and series I take from Blu-ray UHD Picture Quality Rankings PQ Tiers July 2017 at avsforum. For series I usually choose 2 CRF higher or go by the amount of episodes they have per season as a rough guideline -- and by how much I like them.

Without noise reduction I'd increase CRF by 1. With noise reduction I figure CRF needs to be one step lower to compensate for an increased chance of artifacts, but on the plus side the bitrate is used for detail that actually matters to me. Sound bitrates should be more or less proportional to the video bitrates between presets.

Regarding Atmos / DTS-X, I'm not sure if or when I'd keep it, especially if the tracks are lossless, which I think is overkill. I'd very much prefer their lossy variants, but there's no readily available encoder for that, is there?

In general I suppose the presets I'd use most often are Q2 (CRF=18 for movies) or Q3 (CRF=20 for TV shows).


I also like JD17's spreadsheet for presets, although I guess those are more for grain keeping.