[libcamera-devel] softISP for libcamera

[Pavel Machek]

Hi!

> > I'd really like to take still photos. It is one of main use cases.
> > 
> > That means
> > 
> > 1) showing some kind of preview, best at 30fps but 10fps would
> > do. Fortunately screen does have way lower resolution than sensor, and
> > low-quality debayer+downscale is rather easy to do. Just treat GRRB
> > block as one pixel...
> > 
> > 2) saving full resolution photo. Best saving raw bayer data.
> > 
> > For that, it would be very nice to have statistics computation
> > decoupled from actual debayer.
> 
> We are very likely to go this route (decoupling statistics computation
> from debayer).

Good, thanks. It will also mean statistics can be available during
bayer capture, which is needed for AE.

Can you cc me on next round of patches?

> > And that's wrong, right? :-).
> 
> Yes, this way we do loose part of image data. Using the full 10 bits
> for further processing would improve the image quality.
> 
> > Let me explain. RGB888 has 8 bits per pixel, non-linear. So debayer
> > should really take 10 bits, and apply the correction. It may be called
> > gamma or something, I'm sure list knows.
> 
> Right. Going from RAW10's 10 bits (linear) to RGB888's 8 bits (non-linear)
> should be better done during the gamma correction stage. Rather than cutting
> the 2 LS bits off before any processing is done.
> The excuse is that in the current patch set there is no support for gamma
> at all (which also makes the picture look dark and low contrast). And I was
> also saving some CPU cycles in the easiest way.

Ok, so it was known, good.

Best regards,
								Pavel
-- 
People of Russia, stop Putin before his war on Ukraine escalates.
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