Re:AVIF support enabled by default in Firefox 86
by fireattack on Saturday January 09, 2021 @08:20PM
(#25707311)
That "Flat illustration" lossy AVIF case seems to have subtle but noticeable color shift on large pure color areas where webP doesn't have (check the background of the second row, third col figure). What causes this?
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Re:AVIF support enabled by default in Firefox 86
by astrange on Saturday January 09, 2021 @08:23PM
(#25707353)
Really? I don't see any difference, except I do see a pixel shift if I switch between uncompressed/AVIF.
This could happen due to DC shifts (one pixel gets quantized, the rest are coded as a difference from it), or a mistake in the post-decoding pipeline (gamma/colorspace correction).
Re:AVIF support enabled by default in Firefox 86
by fireattack on Saturday January 09, 2021 @08:26PM
(#25707393)
I just modified my comment to make it more clear what I meant.
But you're right, probably just error due to compression/quantization etc. in DC shift or in colorspace conversion. It seems to happen in low quality JPEG too after I did some quick tests myself.