Gamma error in picture scaling

Re:Gamma error in picture scaling by mark-r on Thursday January 03, 2019 @09:55PM (#18821608)

I had this idea a long time ago but never actually tested it. Now I have: http://marksblog.com/gamma-resize/. The square/sqrt method gets at least 80% of the quality but should be quick to compute on a modern processor.

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Re:Gamma error in picture scaling by jacobolus on Thursday January 03, 2019 @10:02PM (#18821633)

sRGB gamma encode/decode is a natively provided hardware feature on GPUs, and is plenty fast. There’s really no excuse in 2019.

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Re:Gamma error in picture scaling by baybal2 on Friday January 04, 2019 @02:17AM (#18822510)

The irony is that all accelerated hardware resizers available on ARM SoCs that I know are also not gamma aware.

This is why downscaled videos feel to have more contrast, or solarised due to bruteforce compensation on most Android devices.

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Re:Gamma error in picture scaling by AstralStorm on Tuesday January 08, 2019 @03:06AM (#18854071)

Those LUT or power or logarithm functions are not free... linear light scaling is about 2x slower in practice. Not that it matters until you get to 8K.

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Re:Gamma error in picture scaling by mark-r on Thursday January 03, 2019 @10:46PM (#18821818)

That's an interesting point. The GPU should do the resizing too if they're using it.

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