OK, we went with "Y" for single channel special case. For >1 channel, default names are R, G, B, A, channel4, ...
In any case, this will solve any weirdness coming from incorrectly labeling alpha where almost certainly plain old grayscale is intended. > On Jun 15, 2016, at 4:21 AM, Karl Rasche <[email protected]> wrote: > > For DWAA/B compressed openexrs, .R and .Y would be lossy compressed, whereas > .I would not. So from that perspective either would suffice. > > On Wednesday, June 15, 2016, Larry Gritz <[email protected] > <mailto:[email protected]>> wrote: > OK, preliminary proposed fix here: > https://github.com/OpenImageIO/oiio/pull/1434 > <https://github.com/OpenImageIO/oiio/pull/1434> > > I'll let it sit for a few days for comment before committing. If others chime > in that R is not smart and most people prefer Y or something, we can revise. > > > >> On Jun 14, 2016, at 9:50 PM, Jonathan Tilden (2K) <[email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');>> wrote: >> >> For us bc4 (single channel dds) and bc5 (two channel dds for tangent space >> normals) are read in shaders as .r/.x or .rg/.xy >> >> To follow with that logic, I'd just suggest R >> >> >> >> Sent from mobile. >> >> -----Original Message----- >> From: Larry Gritz [[email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');>] >> Sent: Wednesday, June 15, 2016 12:41 AM Eastern Standard Time >> To: OpenImageIO developers >> Subject: [Oiio-dev] RFC on Auto-naming of channels >> >> Very few file formats support explicit naming of channels in the files. For >> those that don't (i.e., everything but OpenEXR and a couple other >> stragglers), we impose a convention: >> >> * 1 channel is called A. >> * 2 channels are I, A. >> * 3 channels are R, G, B >> * 4 channels are R, G, B, A >> * >4 channels are R, G, B, A, channel4, channel5, ... >> >> I'm concerned now about the 1 and 2 channel cases. "A" is a special name, >> and designates a channel as alpha, and there are a variety of places where >> where alpha is treated specially. >> >> So I want to revisit the conventions for naming channels of 1 and 2 channel >> images, for formats that don't supply channel names in the file. >> >> Suggestions? What's the best name for a single channel image? >> >> R? Y? I (for intensity)? Grey? (ugh, gray?) >> >> >> -- >> Larry Gritz >> [email protected] <javascript:_e(%7B%7D,'cvml','[email protected]');> >> >> >> _______________________________________________ >> Oiio-dev mailing list >> [email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');> >> http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org >> <http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org> >> _______________________________________________ >> Oiio-dev mailing list >> [email protected] >> <javascript:_e(%7B%7D,'cvml','[email protected]');> >> http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org >> <http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org> > > -- > Larry Gritz > [email protected] <javascript:_e(%7B%7D,'cvml','[email protected]');> > > > _______________________________________________ > Oiio-dev mailing list > [email protected] > http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org -- Larry Gritz [email protected]
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