That is not really possible unless you use the hidden, unsupported, experimental GPU effects. The reason is because everything is done on CPU, and it is too slow to transfer the uncompressed full depth, full frame rate video over the bus to the GPU RAM. Well, that and because I did not program another option or pathway, and you get what I give you.
That is because you are assuming the old information you read here or elsewhere is still correct, but things change…
mlt_image_format=rgb24
is no longer correct since several version. It is now simply “rgb” but we do not know what version you are using.
color_range=jpeg
Since a few versions there is now a Color range in the Video tab. It sets color_range to “pc” but “jpeg” works too. This has no affect when using RGB for output if you choose that using pix_fmt.
Is Shotcut capable of outputting a un-sub-sampled 4:4:4 rgb24 file at all?
When can we see Shotcut do all processing in rgb24 and allow files to be edited and saved without any colour sub-sampling as yuvj444, yuv444 or rgb24 directly?
If you use the new correct value for mlt_image_format, it should be fine if you avoid using YUV-only filters such as all of the Old Film and Reduce Noise ones. Also, you can skip using the pix_fmts with ‘j’ in them as they are not used anymore for encoding will full range.
Here is a link to a reply with a list of things that are YUV-only to avoid: GoPro, full color range and pix_fmt=yuvj420p -- what to hope for and what to avoid? - #2 by shotcut