WebPShop VS rav1e

Grab a the webp plugin for Photoshop: https://developers.google.com/speed/webp/docs/webpshop

Knock yourself out mate

Webp is a newer format and adoption hasn't reached universal levels yet, but there's a free (official) Photoshop plugin: https://developers.google.com/speed/webp/docs/webpshop. It compresses well and can store lossless data.

This fixes it

Try the free Squoosh.app from Google, you can see before and after at the same time. Ideally you'd use webp as the format, it's supported by most browser and WP since 5.8. They also have a webp plugin for Photoshop which uses the same algorithm, meaning that you can try with the before and after on their site and test different percentages, and then replicate or automate it in Photoshop.

most common would be to use Photoshop with Google's WebPShop plugin

Sure. You'll see it very often in codec implementations. From rav1e, a fast AV1 encoder mostly written in Rust: https://github.com/xiph/rav1e/tree/master/src/x86

Large portions of the algorithm have been translated into assembly for ARM and x86. Shaving even a couple percent off something like motion compensation search will add up to meaningful gains.

Or the current reference implementation of JPEG: https://github.com/libjpeg-turbo/libjpeg-turbo/tree/main/sim...

Again, if anything AOM would be the one restricting licenses to AV1 (if they chose to) except AOM has stated and also published AV1 in a way to allow license free access to development (which allows people to make forks of the official build like it's open source) and usage. (1)(2) I don't see why they would suddenly change this.

You can speed up the sampling process with --vmaf n_subsample=5, which in my experience works more accurately than either 2 or 4, possibly due to this bug/feature present in multiple encoders. You might also need to manually set the number of threads used for VMAF calculation with --vmaf n_threads=16, but YMMV.

That remember me of https://github.com/xiph/rav1e which is an AV1 encoder

I put in the request for ffmpeg passthrough mastering-display data a few years ago and haven't heard of any support yet.

It's getting there.. Initial steps for FFmepg: https://patchwork.ffmpeg.org/project/ffmpeg/list/?series=8444 rav1e: https://github.com/xiph/rav1e/pull/3000

It's entirely possible to re-use bits of other HW encoders for the first pass (motion estimation, etc).