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Comment by brucethemoose2 | Hacker News Reader

Running a denoising filter through ReShade or ffmpeg (or better yet with VapourSynth post processing for non live streaming) can help.

In fact, hardware encoders have excellent built in denoising (and other postprocessing) functions. But they are so obscure that less than a dozen streamers on the planet are probably using them... I cant even remember the syntax now, I would have to go look it up in Staxrip and then see if it even works in OBS :/

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Don't the discrete cosine transforms that underlie most video codecs automatically remove noise, as noise is generally high frequency?

Not as well as more computationally expensive algorithms that take more frames/wider areas into account.

And as the blog mentions, noise "tricks" the encoder into blowing its bitrate budget on preserving noise that looks like detail, instead of something more useful.

Don't think so, I read somewhere (like HN) that Netflix purposefully removes noise, transmits it and readds it locally saving some 30% bandwidth.

And the HBO intro is a nightmare.

The DCT is lossless. It's the subsequent quantization step that chops certain frequency components.

Furthermore it is a common (even logical) misbelief that chopping out the higher frequencies after a Fourier transform is filtering them out. Unfortunately this merely zeroes the exact frequencies used to define the bins but leaves a lot of high frequency signals. You need a proper low-pass filter.

How is it possible for those encoders to know that fog is less important than other elements of the game scene?

It seems like removing the elements will ensure bits aren’t wasted on those elements.

It can't, but I have learned that you cant rely on devs to put needed visual features into games, especially old already-released games. And a mild denoising prefilter is a reasonably good universal way to help the hardware encoder, and they tend to be much better at preserving detail than the encoder itself.

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