OpenImageIO::RawInput::open() do all things at one time: open, unpack, than process.
Looks like you do not need this, if you need metadata only.
LibRaw::open_file() will read all metadata, including image sizes (also, EXIF, makernotes, all).
It is really fast (fraction of second or less on SSDs)
But:
image sizes may not be completely correct if aspect ratio is not 1.0
To corect this, use asjust_sizes_info_only() call.
The bad thing that adjust_sizes_info_only() may prevent unpack()/dcraw_process() from working correctly (because sizes to be adjusted another time).
So, if you plan to call unpack() later, you'll need open_file() again.
OpenImageIO::RawInput::open() do all things at one time: open, unpack, than process.
Looks like you do not need this, if you need metadata only.
LibRaw::open_file() will read all metadata, including image sizes (also, EXIF, makernotes, all).
It is really fast (fraction of second or less on SSDs)
But:
image sizes may not be completely correct if aspect ratio is not 1.0
To corect this, use asjust_sizes_info_only() call.
The bad thing that adjust_sizes_info_only() may prevent unpack()/dcraw_process() from working correctly (because sizes to be adjusted another time).
So, if you plan to call unpack() later, you'll need open_file() again.