It would be very helpful if a flag could be added to the CLI tool (demo app) which could be used to validate if a given file was a gain map with encoding supported by libultrahdr. This would be very helpful for a number of reasons, including to be able to quickly determine if processing of an image should be done via ultrahdr_app (if supported) or passed off to another tool (as there are many valid JPGs which are not gain maps).

something like: ultrahdr_app -v myFile.jpg

The result would just be a simple string indicating support or not. Basically, it would indicate if decoding would be possible, without consuming the time and resources to actually decode the image.