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.
_______________________________________________
Oiio-dev mailing list
[email protected]
http://lists.openimageio.org/listinfo.cgi/oiio-dev-openimageio.org

Reply via email to