[libcamera-devel] CCM from CCT: why not mired?

[Laurent Pinchart]

Hi Jack,

On Sat, Jun 06, 2020 at 04:58:00PM +0200, Jack Hogan wrote:
> Hello,
> 
> I am not a programmer but I was perusing the calculate_ccm module in ccm.ccp
> and I noticed that the interpolation factor lambda is computed directly off
> correlated color temperature values in deg K.  Normally this is done in mired
> units, that is the interpolation factor is computed using one over each of the
> cct's, see for instance the DNG SDK.  Is there a reason why it was not done
> this way?
> 
> Also the matrices in apply_saturation the coefficients look incorrect (from the
> 601 standard instead of 709).
> 
> Hope it helps.

Thanks a lot for the feedback. I've added David and Naush in CC, as the
authors of the code I'm sure they know better than I do :-)

-- 
Regards,

Laurent Pinchart