[Cin] Plugins in integer or in float

[Andrew Randrianasulu]

пн, 6 нояб. 2023 г., 18:02 Andrew Randrianasulu <randrianasulu at gmail.com>:

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> пн, 6 нояб. 2023 г., 11:49 Andrea paz <gamberucci.andrea at gmail.com>:
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>> I did some tests to see which of the major CC plugins use floats and
>> which use integers.
>> It turns out that only Blue Banana and Gamma support values above the
>> range (0-1.0). Histogram Bezier reads values above 1.0 but does not
>> use them, returning the usual clip.
>> I start by showing the original image (png) where we can see details
>> in the brightly lit window. In Compositor we don't see those details,
>> getting only pure whites. So CinGG does not support HDR, as we already
>> know (project setting to RGBA-FLOAT). However, even if we don't see
>> them the details are there. To see them we have to do Tone Mapping,
>> for example by decreasing the brightness levels until the values above
>> 1.0 are back inside the range.
>> With the Histogram plugin you can easily do this by lowering the white
>> point along the vertical. No plugins show the details hidden in the
>> white point except Blue Banana and Gamma. Since HDR is handled only in
>> floating point (there are no values outside the range 0-255 or 0-1023,
>> etc.), then I believe that all plugins work on integers except the two
>> mentioned above.
>>
>
> this is a bit strange because I remember Adam's page showing raw file
> processing where difference was there, in hv 2.x era  ....
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>
> https://web.archive.org/web/20100501142034/http://www.heroinewarrior.com/cinelerra_shots.php
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> oh, even 1.x era!
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> https://web.archive.org/web/20100526091542/http://www.heroinewarrior.com/movies.php
>


https://web.archive.org/web/20040529041549/http://heroinewarrior.com/cinelerra_8bit.jpg

but yeah, this one talks about 10 vs 8 bit per channel output and 16 bit
per channel (not float) processing in cinelerra 1.x


> are you sure you have 16 bit per channel  png as input, with levels going
> up above 255?
>
> same with exr, from, for example Blender or Natron as input?
>
> or may be you run into fact that values clips when processed by any but
> those two plugins? Then there must be some bug preventing negotiation of
> float colorbuffers for plugins somewhere ...
>
> can you try another "lowering" tecnique, like creating 0.75 exr and
> subtract it from overbright image as layer/track mode?
>
> The test video can be found here:
>> https://streamable.com/rh62t9
>
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