Hi,
I have data converted into 16 bit ProPhoto RGB. I want to as fast as
possible convert this to Lab, do some changes in Lab mode and convert back
to ProPhoto RGB again.
The first conversion is fine:
-------------------------------------------------------
//Convert ProPhotoRGB to ProPhotoLAB
lcmsPPProfile :=
cmsOpenProfileFromMem(rStreamProPhoto.Memory,rStreamProPhoto.Size);
lcmsLABProfile := cmsCreateLabProfile(NIL);
lcmsTransform := cmsCreateTransform( lcmsPPProfile, TYPE_RGB_16,
lcmsLABProfile, TYPE_Lab_16,
INTENT_PERCEPTUAL, 0 ); //normal
precalc
for y := 0 to CurrentBitmap.Height-1 do
cmsDoTransform(lcmsTransform, CurrentBitmap.ScanLine[y],
CurrentBitmap.ScanLine[y],
CurrentBitmap.Width);
cmsDeleteTransform(lcmsTransform);
//Timing inc createTransform on 6MP image
//1340 ms w/ 0 in precalc!!
-------------------------------------------------------
and 1340 ms is much faster than I am able to do this... and if I have the
transform cached, the time goes down a little more for the Transform only as
well. The LAB image is verified to be exactly as expected.
BUT, even when doing nothing to the image, I have problems getting this
equally fast back to ProPhoto RGB:
-------------------------------------------------------
lcmsTransform := cmsCreateTransform( lcmsLABProfile, TYPE_Lab_16,
lcmsPPProfile, TYPE_RGB_16,
INTENT_PERCEPTUAL, 0 ); //normal
precalc
for y := 0 to CurrentBitmap.Height-1 do
cmsDoTransform(lcmsTransform, CurrentBitmap.ScanLine[y],
CurrentBitmap.ScanLine[y],
CurrentBitmap.Width);
cmsDeleteTransform(lcmsTransform);
//Timing inc createTransform on 6MP image
//3230 ms w/ 0 in precalc!!
-------------------------------------------------------
Why does that 2nd transform take that much more time? 3230 ms vs. 1340 ms ?
Is this just the nature of things, or am I doing something wrong?
Or - is there any alternative ways of doing this... ?
Any hints would be appreciated...
regards
Magne
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