FCPX10.4 REC2020 HLG share to Youtube

Hi All,

I have FCPX 10.4 and have recorded some video from my Sony PXW-Z150 camcorder which is set to HLG mode.

I have created a library with a wide colour gammut and my project is selected as HLG.

When I try to upload a clip to Youtube I get an yellow warning triangle on the export telling me that the file I'm trying to upload is 8 bit. This is for footage that has been captured in 4:2:2 10bit HD and 4:2:0 8 bit in HDR.

The FCPX Share to youtube box shows I'm uploading REC2020.

Whatever I seem to do Youtube doesn't recognise my footage as being HLG and won't flag it as such, meaning it won't trigger HLG mode on my LG TV.

Any ideas of a working HLG / HDR workflow?

Thanks,

Simon.