Qimage doesn't determine this: it is part of LibRaw.  Since the CR3 format is a relatively new format that is unsupported outside of Canon, LibRaw is reverse engineering the format as quickly as possible but not all camera models or CR3 variants are fully supported feature-wise.  I'm sure that eventually LibRaw will catch up and when it does, Qimage will automatically support those missing features.

Things like this will continue to happen as long as companies like Canon continue to arbitrarily change their formats while keeping specs on the format hidden/proprietary.

Regards,
Mike

All of us who use LibRaw have our own customizations, fixes, and workaround that we make to the original code whenever we see problems.  Post a sample CR3 and give a link to one where rotation isn't working.  It's possible there could be an easy fix for that parameter not showing.  There are also multiple functions in LibRaw for developing raws including thumbnail extraction, embedded JPEG extraction, file/open, parameter reading functions where you read only image headers, etc.  Sometimes with undocumented formats and reverse engineering, some of those functions work while others need a touchup so depending on what functions are used (and at what time), two programs can display different results.

Mike

Just had a chance to look at the CR3 thoroughly.  The version of LibRaw that I'm using reports EXIF_orientation as zero (not rotated) on the one that should be rotated.  Looks like I'm going to have to wait until the next LibRaw update which should fix it.

Mike