[PalleO]

I know this last post is a bit old, and I don't know if someone has found a solution for this yet. I haven't been able to find some useful information about a solution anywhere.
Just want to say that I experience the same problem. I have just bought a Raspberry Pi 4B, and noticed the washed out colors at once. Funny thing, I've been using Vero 4K+ with OSMC for the last couple of years, and I never had these problems with Vero. The colors looks nice and vibrant on that device, but on Rpi its useless. How come Vero can handle the HDR files perfectly?

The Vero 4K/4K+, like most AMLogic S9xx series platforms, supports HDR10 Rec 2020 output and also supports AMLogic's HDR10 Rec 2020->SDR Rec 709 tone mapping conversion.

Currently the Pi 4B doesn't support HDR10 or Rec 2020 output AIUI and has a different HDR10 Rec 2020->SDR Rec 709 conversion I believe (if it has any at all).  Whilst the core codec used for HDR10 is usually 10-bit h.265/HEVC - which the Pi 4B has no problems playing and decoding (though at one point it struggled with higher bitrates) it can't output this as Rec 2020 HDR10 flagged video (hence the possible desaturated colours, grey blacks etc which are typical of HDR content displayed unconverted as if it is SDR. ISTR that there is an HDR->SDR conversion of some sort potentially now, but it may not be that great) 

I would not recommend a Pi 4B for replay of HDR10 and/or Rec 2020 material currently.

Almost all 4K/UHD/2160p HEVC movies are going to be HDR10 Rec 2020 (as UHD Blu-rays are pretty much 100% HDR10 - even those with Dolby Vision have a core HDR10 stream).  

Almost all 1080p movies are going to be Rec 709 SDR - which will play fine and be output in Rec 709 SDR.

Thank you for your explanation, Noggin. Makes good sense. But what doesn't makes sense is the YouTube add-on. Here you can switch HDR on and off, and there's a big difference in colours. All colours are shown fine when I disable the HDR option. Wouldn't it be possible to make the same option in the general video system settings?

[noggin]

I know this last post is a bit old, and I don't know if someone has found a solution for this yet. I haven't been able to find some useful information about a solution anywhere.
Just want to say that I experience the same problem. I have just bought a Raspberry Pi 4B, and noticed the washed out colors at once. Funny thing, I've been using Vero 4K+ with OSMC for the last couple of years, and I never had these problems with Vero. The colors looks nice and vibrant on that device, but on Rpi its useless. How come Vero can handle the HDR files perfectly?

The Vero 4K/4K+, like most AMLogic S9xx series platforms, supports HDR10 Rec 2020 output and also supports AMLogic's HDR10 Rec 2020->SDR Rec 709 tone mapping conversion.

Currently the Pi 4B doesn't support HDR10 or Rec 2020 output AIUI and has a different HDR10 Rec 2020->SDR Rec 709 conversion I believe (if it has any at all).  Whilst the core codec used for HDR10 is usually 10-bit h.265/HEVC - which the Pi 4B has no problems playing and decoding (though at one point it struggled with higher bitrates) it can't output this as Rec 2020 HDR10 flagged video (hence the possible desaturated colours, grey blacks etc which are typical of HDR content displayed unconverted as if it is SDR. ISTR that there is an HDR->SDR conversion of some sort potentially now, but it may not be that great) 

I would not recommend a Pi 4B for replay of HDR10 and/or Rec 2020 material currently.

Almost all 4K/UHD/2160p HEVC movies are going to be HDR10 Rec 2020 (as UHD Blu-rays are pretty much 100% HDR10 - even those with Dolby Vision have a core HDR10 stream).  

Almost all 1080p movies are going to be Rec 709 SDR - which will play fine and be output in Rec 709 SDR.

Thank you for your explanation, Noggin. Makes good sense. But what doesn't makes sense is the YouTube add-on. Here you can switch HDR on and off, and there's a big difference in colours. All colours are shown fine when I disable the HDR option. Wouldn't it be possible to make the same option in the general video system settings?

I suspect in the YouTube add on it is switching between an HDR stream from YouTube and an SDR stream from YouTube - not converting the HDR YouTube stream to SDR. Very different approach. (It's analogous to having two video files to chose to play on your Pi - an HDR Rec 2020 one and an SDR Rec 709 one - rather than converting the Rec 2020 HDR to Rec 709 SDR you just play back the Rec 709 SDR version instead.)

[PalleO]

The Vero 4K/4K+, like most AMLogic S9xx series platforms, supports HDR10 Rec 2020 output and also supports AMLogic's HDR10 Rec 2020->SDR Rec 709 tone mapping conversion.

Currently the Pi 4B doesn't support HDR10 or Rec 2020 output AIUI and has a different HDR10 Rec 2020->SDR Rec 709 conversion I believe (if it has any at all).  Whilst the core codec used for HDR10 is usually 10-bit h.265/HEVC - which the Pi 4B has no problems playing and decoding (though at one point it struggled with higher bitrates) it can't output this as Rec 2020 HDR10 flagged video (hence the possible desaturated colours, grey blacks etc which are typical of HDR content displayed unconverted as if it is SDR. ISTR that there is an HDR->SDR conversion of some sort potentially now, but it may not be that great) 

I would not recommend a Pi 4B for replay of HDR10 and/or Rec 2020 material currently.

Almost all 4K/UHD/2160p HEVC movies are going to be HDR10 Rec 2020 (as UHD Blu-rays are pretty much 100% HDR10 - even those with Dolby Vision have a core HDR10 stream).  

Almost all 1080p movies are going to be Rec 709 SDR - which will play fine and be output in Rec 709 SDR.

Thank you for your explanation, Noggin. Makes good sense. But what doesn't makes sense is the YouTube add-on. Here you can switch HDR on and off, and there's a big difference in colours. All colours are shown fine when I disable the HDR option. Wouldn't it be possible to make the same option in the general video system settings?

I suspect in the YouTube add on it is switching between an HDR stream from YouTube and an SDR stream from YouTube - not converting the HDR YouTube stream to SDR. Very different approach. (It's analogous to having two video files to chose to play on your Pi - an HDR Rec 2020 one and an SDR Rec 709 one - rather than converting the Rec 2020 HDR to Rec 709 SDR you just play back the Rec 709 SDR version instead.)

Ok, that makes sense :-)