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Old 4th June 2020, 21:12   #1  |  Link
`Orum
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Join Date: Sep 2005
Posts: 178
Any way to get better detail in dark areas? (libaom/aomenc)

With AVIF finally getting support in Firefox, I've been eager to make use of it. Doing some testing last night, using aomenc to produce the image, I found it's definitely better overall than WebP. However, it seems to struggle in the darker areas of images, where WebP would do well (though WebP did worse in bright areas).

So, does anyone know any tips to get more even quality over an image? I was using constant quality (--end-usage=q), and am wondering if cq ratecontrol would be better. Alternatively, I was thinking various aq-modes might be of use. Or am I completely off base, and is there something entirely different that I should be looking at, like using a different AV1 encoder?

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Edit:
After several hours of testing, I can definitely say that --aq-mode=1 looks better than the default (0). The quality gains are most noticeable in areas that are dark, noisy, or low-contrast. I'm curious what others think though, as this was entirely subjective testing. I also looked at AQ 2 & 3, but they produced identical results to AQ 0.

If doing your own tests using various AQ, realize that files encoded with AQ 1 will have a different size than AQ 0, either larger or smaller. To account for this during my tests, I stacked the deck in AQ 0's favor, by lowering the quantizer for AQ 0 (or raising it for AQ 1) if AQ 0 produced smaller sized files than AQ 1. AQ 1 won or tied AQ 0 in all cases, with bright, low-noise, high-contrast images being the toughest to tell apart.

I still need to test other rate control methods to see if they help or hurt, but again please let me know if you think there are other things I should test out.
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Last edited by `Orum; 5th June 2020 at 05:33.
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