Vero 4K flat colours when sending to 709 4k projector

HDR/Rec.2020 on an SDR/Rec.709 display with no attempt to convert makes the colors look washed out and unsaturated, not dark. You’d likely see pictures that look more saturated with a non-HDR, Rec.2020 source. Colors on my calibrated display look pretty good overall, so I think the Rec.2020 to Rec.709 works OK…it’s just the HDR to SDR that needs some work, to fix the black and white crush and better resolve details at the two ends of the brightness curve.

Thanks for that, what I was trying to say was that I didn’t feel it was a HDR to SDR issue. You say 2020 to 709 works ok and I’d kind of expect it to.

I’ve sent Sam some photos so hopefully he’ll either go, yes, that’s kind of where we are right now, or will go, yeah, that looks a bit odd.

Yes I’d perhaps describe the colours as washed out. Is there some way to check whether the conversion is happening in the box ?

Btw the display is 4k, not sure why something in the logs suggests otherwise. I might have the interface resolution set at 1080 but assume it switches when playing a 4k file.

It will if you enable Adjust Refresh Rate in Settings -> Playback.

Yes it is enabled. Did you get the photos ?

Yes – I’ve replied to the ticket. For others that might be interested, I think that we may be able to make some presets available in Kodi in the future.

Sam

Hi Sam, you didn’t answer my question. Is the colour difference between the two photos that I sent one of the bluray, one of the uhd rip, consistent with how you expect the player to behave in its current form ?

It depends on the rip you are playing; but in short yes.

Sam

The customer is now returning their device. But they’ve raised a good point.

Obviously we’re always keen to improve things, so if anyone would like to take part in some testing of improvements for colourspace conversion, let me know.

Sam

I would be delighted to help with this. Shame about the return, I think the Vero 4K is an exciting device and I look forward to seeing what more it can do.

On board for testing of 4K HDR bt.2020 10-bit → 1080p SDR bt.709 8-bit conversion. I guess, the resolution downscaling isn’t any issue, but the rest would be what you’re referring to. I can help with that :+1:t2:

I also want to test Rec.709 10-bit (both RGB and YCbCr), as the Panasonic plasma supports both. It also supports 4:4:4 color, but I think only in RGB. So, part of my testing is going to be finding out if the output mode is an issue.

Same here… I also have a Panasonic Plasma (STW50 generation)… :slightly_smiling_face:

VT50 for me. Not quite as good at black as the VT60, but better than anything until OLED came along.

:heart_eyes::heart_eyes::heart_eyes:

Could I suggest we de-couple ‘colour space’ and ‘colour gamut’ too?

When we only had Rec 601 (+NTSC and PAL) SD and Rec 709 HD - which had similar (if not quite identical) primaries - we used “colourspace” really just to describe the different RGB->YCbCr matrices that the two standards used, even though their gamuts (i.e. the colours they could define) were pretty much identical. Colourspace conversion was simply a case of getting the maths right to convert between the two YCbCr to RGB relationships - the colours remained the same. I think we all ignored that the RGB primaries (in some cases) were slightly different colours.

However now we have Rec 2020 - used for both SDR and HDR. Rec 2020 has significantly different RGB primaries to those used by Rec 709 and Rec 601 (+NTSC +PAL), and encloses a much wider range of colour than the primaries used in Rec 709 encompass. We are no longer simply converting between different RGB and YCbCr “colourspace” relationships. We are now looking at two different gamuts and gamut conversion. The RGB primaries in the Rec 2020 spec define a much wider colour gamut than Rec 709/601 allows for. Converting from Rec 709/601 to Rec 2020 is thus possible pretty much losslessly (Rec 709/601 is a sub-set of Rec 2020 and fits neatly inside) - but you have to do the right maths. However converting from Rec 2020 to Rec 709 (or 601 for that matter) is NOT a lossless process - there are colours you can define in Rec 2020 that are outside the range that Rec 709/601 can carry - so you have to think quite carefully how you do the conversion (and how you map colours that don’t exist in the 601/709 gamut into the 601/709 gamut). There may not be a perfect way of mapping the wider gamut to the narrower gamut and you can’t retain the full content of the Rec 2020 gamut after the conversion. Things won’t look ‘as nice’ even if you do at the best possible conversion.

This is all before you then take into account HDR->SDR mapping (where you have to do even more complex processing to try to make the quality loss as ‘pleasant’ as possible)

Of course if you don’t do anything you end up with a horrible mess of thin, desaturated, pictures that look the wrong colour

I would like to tune in. I also have a 4k TV which does not support HDR (Panasonic TX-60CXW754). I bought it because i wanted a 4k TV with 3D Support, but now i think the Vendor gave me a bad advice when choosing the Panasonic concerning HDR. I was not aware about the disadvantages of having a TV with no HDR Support. So i would also appreciate it to have a Setting in Kodi where i can force the HDR to SDR conversion with different Presets for the colorspace conversion. I am very confident that there will be a Solution in the Future because the support here is great. I hope that Panasonic is still making 4k TV’s with 3D support when i am able to buy a new TV :slight_smile: Till then i am waiting what improvements will come for the Vero. If there is something to test i am going to help where i can.