assemble the Aux data to heif request #316
Description
Describe why it is important and where it will be useful
It seems that the library only supports decoding the aux data from the heif image, but no API for reverse. I want to add the gain map data to the image and haven't found a way to do so.
Describe your proposed solution
Not sure.
Describe alternatives you've considered, if relevant
No response
Additional context
No response