Kitsu not maintaining uploaded QT's colour space for Revisions

[PeteDraper]

Kitsu is not maintaining the same Colour space for previews. Uploading a sample in Rec2020 ST 2084 converts to Rec709 with a major colour shift.

Steps to reproduce: Upload aforementioned Rec2020 ST2084 sample as Revision, resulting generated QT is converted to Rec709 with colour shift.

Expected output: same colour space, just converted to h.264 for preview purposes

[frankrousseau]

Hello @PeteDraper, do you know if it's something possible with FFMPEG? We didn't dig into colorspaces yet with it.

[PeteDraper]

yes I believe so. FFMPEG can do wondrous things. basically, you just don't want to change the colour space of the source

[frankrousseau]

Ok we will see what we can do about it. If you can provide a test video, that would help.

[PeteDraper]

You can shoot anything with your iPhone on cinematic mode which outputs a Rec2020 (HLG2100) and upload that. The resulting Revision file doesn't tone map nicely and converts to a rec709. Would expect it to convert to a h.264 / h.265 but maintain the same colour space as the source material.

[tetsuoanimation]

As discussed on discord, here's a deepdive on ffmpeg and colorspaces from the canva blog.

https://www.canva.dev/blog/engineering/a-journey-through-colour-space-with-ffmpeg/

[mathbou]

Some additional links from the ASWF Media Review working-group, they try to establish good encoding practices for VFX review:

• https://richardssam.github.io/ffmpeg-tests/
• https://wiki.aswf.io/pages/viewpage.action?pageId=16031068