[Cin] "color hell"

[Andrew Randrianasulu]

On Tuesday, July 13, 2021, Andrea paz <gamberucci.andrea at gmail.com> wrote:

> Finally I managed to patch! On Phyllis' suggestion I entered the
> absolute path of the files to patch every time it didn't find them.
> Below is the test I did.
>
> I downloaded the app mentioned from the link and created a video on
> smartphone; as mentioned in the link the video produced is: YUV,
> NTSC,color range:tv; primaries=BT 601 PAL; Transfer=BT 601 and
> Matrix:BT 601 (a horror in this day and age where broadcast worldwide
> uses HD and rec 709). In CinGG without patching you have a slight
> change in brightness going from 601 to 709 and vice versa (correct is
> 601!); you have a bigger change going from Mpeg to Jpeg (correct is
> mpeg!).
> Applying the patch and importing the same video as before you have
> some difference between BT601 PAL and BT601 NTSC (correct is BT601
> NTSC). Both are different from BT 709. Thanks Andrew, you did a great
> job for me!


one concern is... while input video claims itself to use  bt 601 pal
primaries - you get correct result wuth bt 601 ntsc? may be it was tagged
wrong, or ffmpeg flipped it?


>
> In CinGG, to make a transcode there is the excellent ColorSpace plugin
> that works just for these changes of color spaces.
> I once asked if it was possible to integrate it into the "Transcode"
> function so that it would work for all project sources and not just
> the edits to which the plugin applies. But I think it's a complicated
> job....
>

code is already written, even with OpenGL accelerated preview... so may be
it can be reused, or just tell swscale (because we mostly use ffmpeg here)
to do some colorspace changes for us...
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