Hello Guys,

Just checking if someone would have an idea what could be the problem.
Any help would be appreciated.
Best
Dave.


Dave Lajoie
R&D Director |  Directeur R&D
 [image: Digital-District] <http://www.digital-district.fr> 5605 Avenue de
Gaspé, Suite 408  |  Montréal, QC H2T 2A4
Tel  (514) 360-3253  ext. 130

On Sun, Sep 21, 2014 at 10:39 AM, Dave Lajoie <
[email protected]> wrote:

> Hello Guys,
>
> I have a slate generation tool which take any file format and generated
> slated images sequences, or still image. I have problem with jpeg source
> files, where there is quantize / banding issues ( it gets worst once
> processed). So I have search the oiio doc, and found the section about how
> to resolve quantize issues.
>
> However, despite my best effort, I cannot get rid of the quantize.
>
> Long story short, here is what I am attempting to do in the code:
>
> - Load UINT8 sRGB jpg file as ImageBuf instance,
> - Remove sRGB from input ImageBuff using pow() <<< this creates the
> quantize issue
> - "over" operation into HALF ImageBuf Instance.
> - write out the HALF ImageBuf Instance as .exr
>
> Here are few questions:
>
> 1) Is there a way to load a UINT8 file, and load it straight into HALF
> linear space ImageBuf without having to convert/process the UINT8 ImageBuf?
>
> 2) Is there a way to convert ImageBuf format in-place? for instance I have
> loaded an jpg sRGB into ImageBuf instance, and I want to convert it to
> HALF. Is there a way to do this without having to use the
> pixel/scanline/tile level api? ( looking for an atomic operation here,
> since python can be slow for pixel level operations. :) )
>
> 3) ImageBugAlgo are assumed to be done in linear space, right?
> Also there is not implicit color space conversion, since it takes the
> buffers "as is" and apply the math.
>
> 4) Dithering doesn't appear to be working. When is dithering being
> applied? on image buf write? during ImageBufAlgo operations?
>
> I have a python test script that demonstrate the problem ( will sent it
> privately )
>
> I am sure I am doing something stupid and I cannot see it. :)
>
> Tx for the help
> Best
> Dave.
>
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