Endianness and '.raw' files

[canon-cmre-allan-barklie]

Hi,
I've been looking through the code and the docs but I thought I'd better ask to me sure.

I see that both OpenJPEG and Kakadu use a convention whereby '.raw' files are big endian and '.rawl' files are little endian.

I'm not sure what the current intended behaviour with OpenJPH is for '.raw' files. I have been experimenting with signed 16bit little endian data and that seems to work fine, is little endian currently assumed for '.raw' ? is there a flag i'm overlooking? or something else?

Thanks,
Allan.

[aous72]

Hi Allan,

The extension ".raw" was added in an ad-hoc way to OpenJPH.
Currently only little endian is supported, but has the extension of ".raw".
I would like to follow OpenJPEG and Kakadu, but that would break existing adopter's code.
So I am not sure what is the best course of action.

I am open to suggestions.

Kind regards,
Aous.

[canon-cmre-allan-barklie]

Thanks, that's great to get confirmation of current behaviour.

As for suggestions:

Maybe something like "When the source is a .raw file, the data is assumed to be in little endian format. Big endian for .raw files is not currently supported." added to usage_examples.md would give good cover for now.

For the future I suspect it may need to be a phased journey maybe it would be good to add .rawl, also as little endian. And then separately maybe add a bool flag for .raw behaviour with default little endian but also a deprecation warning with an aim to eventually move to the same pattern as the other libraries.

[aous72]

Thank you for this suggestion; it is very useful.

Kind regards,
Aous.

[aous72]

Updated usage_examples.md, now I need to update the code.