[Lag Free Screenshots] Add WebP Support

[Zexxx]

WebP has way faster compression algorithm along with much smaller file size compared to png. With encoding being faster this could help reduce the lag during the screenshot process.

[dakyneko]

I've implemented this but @knah rejected the idea we would depend on other library like libwebp. I asked already 6 months ago and recently but same answer. So either I'll publish my own fork or he will accept a PR, who knows ;)

Also that claim about encoding being faster is not true, it's slower than both png and jpeg in my benchmark even as I'm using the method = 0 which is the fastest. That said I still think that cons is shadowed by the pros of webp.

[Zexxx]

That's odd that it's slower for you, maybe i should test it properly and not just use cwebp as a mini test. Although i would be very interested in it regardless if its slower than png for those benefits of significantly lower sizes. I had a png straight from in game at 16k come in at 192mb when converted to 66mb. Altho please do make that fork!

[dakyneko]

Altho please do make that fork!

We'll see if @knah is wiling to react. If not I could make a fork but beware that maintaining fork is effort. Tho it's true LFS itself didn't change much over time. I could consider making a fork if more people are interesting :thinking: I do have an open PR which improves speed by a lot https://github.com/knah/VRCMods/pull/226 (still not merged), so yeah. I could ask to maintain the package at this point maybe :P I would be more active.

That's odd that it's slower for you, maybe i should test it properly and not just use cwebp as a mini test.

I'm not sure how you bench or where you saw that webp compression speed would be faster. In my experience and sources like: https://groups.google.com/a/webmproject.org/g/webp-discuss/c/mu1RYRAe72A?pli=1 or https://siipo.la/blog/whats-the-best-lossless-image-format-comparing-png-webp-avif-and-jpeg-xl they all agree encoding is slower. I didn't see anything to the contrary. But:

The results look promising on the compression side (up to 50% on some images), however encoding times are very slow - x5 slower on lossy, x10 for lossless compression.

That's not unusual ratio, indeed.

what's faster is the decompression: because of smaller size AFAIK https://developers.google.com/speed/webp/docs/webp_lossless_alpha_study

Decoding speeds faster than PNG have been demonstrated, as well as 23% denser compression than what can be achieved using today's PNG format. We conclude that WebP is a more efficient replacement for today's PNG image format.

That said, it's possible the IO is the bottleneck (esp with hard drives) to write the files down with huge size like ~200MB. Tho that isn't the subject of the bench above. Not sure if that's what you saw? In my testing I have m2 ssd so no bottleneck there.

[dakyneko]

As you know with EAC thing, this won't happen. But if you're interested: I ported lfs to cvr and I added webp support too.