Re: [Openexr-devel] Adobe's Digital Negative Format

[Chris Cox]

At 1:09 PM -0600 9/27/04, Derek Gerstmann wrote:
> Chris Cox wrote:
>
> > > Wouldn't an open standard such as OpenEXR be a better choice?
> >
> > No, OpenEXR is the wrong thing for camera RAW files.
>
> Thanks for clearing this up, and directing me to the documentation.
>
> I freely admit that I know very little about DNG, and this is what
> motivated my post, in hopes that someone could explain its need.
>
> Thanks for the detailed summary and explanation.
>
> ...
>
> The other point that I was interested in exploring was how feasible
> it would be to simply extend the hdr encoding capabilities of OpenEXR
> to provide the functionality needed for storing RAW files.

It is feasible, sure.   But if you know the address@hidden that goes into 
processing RAW files, you probably wouldn't think it was worth the 
time and effort.

Supporting camera RAW files is probably a larger task than supporting 
all of OpenEXR right now.



> Thanks to Florean for pursuing this train of thought:
>
> >  Of course, I would prefer it if digital cameras could directly output
> >  OpenEXR files, performing a high-quality conversion inside the camera.
> >  I guess someone should contact digital manufacturers.  Users demanding
> >  OpenEXR output would probably be most effective.
>
> I agree. It would be really nifty for the camera itself to take
> multiple exposures and convert the RAW data into an OpenEXR
> HDR representation all by itself.

Unfortunately, that would take quite a bit of intelligence inside the 
camera.   You have to remember that the CPU in cameras are very 
simple, and relatively slow.   Think about how long it takes your 
desktop CPU to convert multiple exposures to HDR -- then multiply 
that by 20 or more, and that's about how long your camera would take.
For the time being, I'd rather do multiple exposure conversion as a 
post process.

Of course, in the long run I'd like to see cameras capture HDR 
information directly.
There is some promising research going on....

Chris