Many suggestions of improvement

[Selur]

Please, do not use full quotes and add text into them, since it increases the difficulty to read your stuff.
(specially on mobile devices)
Thanks.

AFAIK x264 do support YUV 4.2.0 lossless ?
I did multiple tests (without any filtering) :
4.2.0 to x264 4.2.0 lossless
4.2.0 to x264 4.2.2 lossless
4.2.0 to x264 4.4.4 lossless
4.2.0 to x264 RGB lossless

You are correct, I mixed some stuff up in my head. I was wrong.
x264 does support it, as does Hybrid.
Lossless requires either 'None' or 'High 4:4:4' as profile.
The 'auto' option for the calculation precision will use the highest supported bit depth supported by the profile.
The 'auto' option for the output color space, does nothing if the avc profile is set to 'None', otherwise it will change the color space to the highest available.
=> I adjusted Hybrid (updated dev version) to make sure that if 'None' is selected, the 'auto'-option for 'output color space' gets deactivated and disabled.

I compared screenshots with the software Diffimg. The only video that is 100% the sale as the source is the x264 4.2.0 lossless, all others have different pixels.

You did not do any 8bit <> 10bit conversions and you did respect that color matrix during RGB <> YUV conversions, right?

I copy Avisynth scripts (or even Vapoursynth script) in Hybrid corresponding folders, would they work in custom script tab (without having to load them manually I mean) ?

No, Hybrid does no autoloading in neither Avisynth nor Vapoursynth, so that will not work.

That was not really what I meant, but rather to set an alert of lack of disk space, unrelated to the output file, just to warn us. For instance if we set it to "2 GB" there'd be a popup saying "Warning : there is less than 2 GB free on your drive".

The option checks whether xy MB are free and if not it does not start the jobs.
So it does what you want, except it does not create a pop-up. (No, I will not add a pop-up for this.)


Cu Selur