Aha, I see where it's going wrong. The --ch (and underlying
ImageBufAlgo::channels() function) notices when you have requested a channel
order that doesn't actually change the ordering, and so takes an "early out"
rather than copy channel data all over the place for no good reason. It's
failing to notice that you may not be changing the order, but you are changing
the names.
I'll prepare a separate fix for that, but in the mean time --chnames is the way
to go when you are only renaming channels but not changing their order. (--ch
would work for renaming, if only at least one channel has its order changed as
well.)
Sorry for the confusion.
-- lg
> On Jan 22, 2016, at 2:52 PM, Larry Gritz <[email protected]> wrote:
>
> If you're just renaming channels in order, this works:
>
> oiiotool in.exr --chnames x,y,z -o out.exr
>
> That should get you unstuck. (I don't remember exactly when --chnames was
> added, sufficiently old versions may lack it.) Meanwhile, I'll look at --ch
> and see if I can't figure out why that isn't working.
>
> Note, however, that channel names work strangely in OpenEXR. There is no
> canonical numerical order in exr, other than alphabetical by channel name.
> But OIIO says that on the app side of an API, RGBAZ always come first, so
> OIIO will reorder the presentation of channels for you (though not their
> actual order in the file). So, oddly, if you "oiiotool -info -v out.exr" in
> the example above, it will report channels "z, x, y". Because it thinks Z is
> depth, and puts it before "other things it doesn't recognize". So just beware
> of this, it's saving the file correctly, but your particular choice of
> channel names is defeating the presentation heuristic that is almost always
> preferable to alphabetical order.
>
>
>
>> On Jan 22, 2016, at 2:42 PM, Larry Gritz <[email protected]> wrote:
>>
>> Never mind. I can reproduce this. Hang on...
>>
>>
>>
>>> On Jan 22, 2016, at 2:33 PM, Larry Gritz <[email protected]> wrote:
>>>
>>> Is it still a problem in 1.6 and/or master?
>>>
>>>
>>>> On Jan 20, 2016, at 11:12 PM, Daniel Flood <[email protected]>
>>>> wrote:
>>>>
>>>> Hi folks,
>>>>
>>>> I'm trying to use oiiotool to take an rgb exr, and change the channel
>>>> names to some arbitrary value, while preserving compression type and
>>>> header metadata.
>>>>
>>>> I tried this, and noticed different results in oiio 1.2 and 1.5. in.exr
>>>> is a rgb exr.
>>>>
>>>> oiiotool in.exr --ch "x=R,y=G,z=B" -o out.exr
>>>>
>>>> In 1.2, this creates an empty exr with the correct channel names (ie xyz),
>>>> but no image. In 1.5 it creates the image, but the channels are RGB.
>>>>
>>>> Can someone point me in the right direction for this? The reason is
>>>> interfacing with external software which expects channel names to be
>>>> certain values.
>>>>
>>>> cheers,
>>>> Dan
>>>>
>>>>
>>>
>>> --
>>> Larry Gritz
>>> [email protected]
>>>
>>>
>>> _______________________________________________
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>>
>> --
>> Larry Gritz
>> [email protected]
>>
>>
>> _______________________________________________
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>
> --
> Larry Gritz
> [email protected]
>
>
> _______________________________________________
> Oiio-dev mailing list
> [email protected]
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--
Larry Gritz
[email protected]
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