Feature request: extend crf-search over more presets at once

[mr44er]

The idea came about because I got my latest energy bill and electricity prices here are brutally expensive. This is the perfect expression of how politicians simply hate the people.

Anyway, I thought that you could do the same thing with multiple presets, just like with -min-vmaf/-max-vmaf, and then decide at the end how long you want to waste power on it and, in relation to that, the file size. For example, if the difference between preset 5 and preset 6 is around 10 MB, preset 6 would be sufficient.

I was thinking something like ab-av1 preset-search --min-preset 0 --max-preset 8 where just ab-av1 preset-search has defaults of --min-preset 6 and --max-preset 8

[stickz]

There is no value added doing this. You can predict the difference before running ab-av1.

[mr44er]

I hear ya and I know that, but there is still a huge gap between quiet material having less movement and actionpacked, many fast scenes. Yes, depending on samples.
Also it doesn't help with file size prediction.

[alexheretic]

This is something I've done with simple scripting on top of ab-av1. It's quite useful for comparing presets with similar VMAF quality output, typically harder to do as you need to search for the crfs that achieve this (exactly what ab-av1 is made for).

However, I'm not sure I see the value yet in having a dedicated command for multi-preset. Were you were thinking of an automated multi-preset crf-search? That could be worth investigating, but we'd need a clear vision of how it would work / why it would be useful. Analysing multiple presets tends to be very slow.

E.g.

# fish shell
$ for preset in 10 8 6 4
     echo "# preset $preset"
     ab-av1 crf-search -i 4kmedia-spacex-launch-demo.mp4 --preset $preset --min-vmaf 98 --samples 1
  end

# preset 10
- crf 32 VMAF 96.10 (9%)
  00:01:25 crf 19 1/1 ######################################################################################### (eta 0s)
Encode with: ab-av1 encode -i 4kmedia-spacex-launch-demo.mp4 --crf 19 --preset 10

crf 19 VMAF 98.19 predicted video stream size 47.87 MiB (27%) taking 2 minutes
# preset 8
- crf 32 VMAF 96.47 (9%) (cache)
- crf 19 VMAF 98.57 (29%) (cache)
  00:00:54 crf 23 1/1 ######################################################################################### (eta 0s)
Encode with: ab-av1 encode -i 4kmedia-spacex-launch-demo.mp4 --crf 23 --preset 8

crf 23 VMAF 98.14 predicted video stream size 38.41 MiB (22%) taking 3 minutes
# preset 6
- crf 32 VMAF 96.56 (9%)
- crf 19 VMAF 98.61 (29%)
  00:02:58 crf 23 1/1 ######################################################################################### (eta 0s)
Encode with: ab-av1 encode -i 4kmedia-spacex-launch-demo.mp4 --crf 23 --preset 6

crf 23 VMAF 98.18 predicted video stream size 38.67 MiB (22%) taking 3 minutes
# preset 4
- crf 32 VMAF 96.91 (7%)
- crf 19 VMAF 98.82 (26%)
  00:06:41 crf 25 1/1 ######################################################################################### (eta 0s)
Encode with: ab-av1 encode -i 4kmedia-spacex-launch-demo.mp4 --crf 25 --preset 4

crf 25 VMAF 98.18 predicted video stream size 26.22 MiB (15%) taking 11 minutes

[mr44er]

Were you were thinking of an automated multi-preset crf-search?

Yes.

why it would be useful

The main purpose should be a quick overview (and having it automated) to see how long it would need to draw power.
Just the easy example (and start with the fastest so you can STRG+C if you are already satisfied with filesize and time estimation):
preset12 -> 200MB ~1 minute
preset11 -> 190MB ~1:30 minutes
preset10-> 188MB ~ 4 minutes
preset9 -> 170MB ~ 6 minutes
preset8 -> 150MB ~11minutes
preset7 -> 130MB ~50 minutes
preset6 -> 100MB ~2hours
preset5 -> 80MB ~3hours
preset4 -> 60MB ~4:30hours
...
preset1 -> 22MB ~6hours
preset0 -> 20MB ~8 hours

One could decide on personal preference between preset8 and preset7...that ~20MB are not worth the 39 minutes more power draw or if the 2MB difference @preset1/0 is worth the smaller file.