Store Deflicker data in CR2 metadata?

[LebedevRI]

Currently Deflicker stores data in sidecar file.
Is there any way to store same data directly in CR2, in some metadata tag?
Or in Copyright notes, that can be inputted through canon menu?

[dmilligan]

What's so bad about the sidecar files? Sure it's possible, but I think writing to the CR2 files would be considered too 'dangerous', there's the potential of corrupting the original CR2 file. It would probably also be rather 'hefty' in terms of how much code you'd need to do it (you'd need to port something like exif tool, there are limited memory resources on these cameras, I don't see the point in wasting them on somewhat pointless stuff like this).

Finally, if you put the info in something like the Copyright notes, you'd need another post processing step (an exiftool command probably) take that info out of the copyright notes and put it back in a sidecar file where the programs that process these files (ACR, UFRAW) expect them to be. In other words, you have to have the sidecar file for ACR anyway, there's no way to make ACR adjust the exposure based on the copyright notes.

The whole point of sidecar files is you avoid touching the original file. Post processing software is already setup to pull metadata from these files, and sidecar files are widely used. Any other solution is suboptimal.

[LebedevRI]

>What's so bad about the sidecar files?
They can be lost.

Anyway, i've almost finished porting Deflicker algorithm into my preferred RAW develop application - darktable
For now, code is located in my branch: https://github.com/LebedevRI/darktable/tree/iop-exposure-deflicker