Ultra HDR is a true HDR image format, and is backcompatible. libultrahdr is the reference codec for the Ultra HDR format. The codecs that support the format can render the HDR intent of the image on HDR displays; other codecs can still decode and display the SDR intent of the image.
uhdr_dec_probe() parses gainmap metadata present in xmp block only. If iso block contains gainmap metadata this is not handled. Add support for same.
Test:./ultrahdr_unit_test