HDR content washed out on SDR tv

[Ponyo 22]

Hi,

 

I recently started trying out 4K UHD content and I noticed HDR colors look washed out on my SDR tv. My understanding of how HDR is supposed to work is that on a SDR tv the HDR brightness info should be ignored, leaving a "normal" picture.

 

Both on the Shield TV and Browser this demo has washed out colors when directly playing or transcoding.

http://4kmedia.org/lg-new-york-hdr-uhd-4k-demo/

 

Is this a bug or is this how HDR content is supposed to look on a SDR tv? In other words; don't buy HDR content unless all your TV's support HDR?

[a5ian300zx 7]

Emby need to be able to do HDR to SDR tone mapping which i believe it cannot do.

[Waldonnis 148]

Hi,

 

I recently started trying out 4K UHD content and I noticed HDR colors look washed out on my SDR tv. My understanding of how HDR is supposed to work is that on a SDR tv the HDR brightness info should be ignored, leaving a "normal" picture.

 

Both on the Shield TV and Browser this demo has washed out colors when directly playing or transcoding.

http://4kmedia.org/lg-new-york-hdr-uhd-4k-demo/

 

Is this a bug or is this how HDR content is supposed to look on a SDR tv? In other words; don't buy HDR content unless all your TV's support HDR?

 

Not a bug.  HDR content uses much larger colourspace (BT.2020/Rec.2020) that needs to be reduced to within the bounds of SDR (Rec.709).  If the "HDR information" isn't properly mapped down to the smaller colourspace, you end up with output like you're seeing (washed out) or overly dark.

 

Emby need to be able to do HDR to SDR tone mapping which i believe it cannot do.

 

Exactly this.  Tonemapping can be complicated and while there are several methods in ffmpeg to do it, there isn't a "best way" as each method has strengths and weaknesses (some are better at detail preservation while others are better at preserving colour accuracy, etc).  I'm sure the Emby team will get to it eventually and pick a method to do it (or offer an option), but until then, it's probably best to treat HDR content as "direct play only" in your mind.  If you do have a mix of HDR/non devices, you could always encode an SDR version and store it using Emby's multi-version support so that you'd have a version to play on your non-HDR devices that won't look terrible .

[majorsl 20]

I'm starting to run into this as well.  Is this on the roadmap somewhere?

[Ponyo 22]

Not a bug.  HDR content uses much larger colourspace (BT.2020/Rec.2020) that needs to be reduced to within the bounds of SDR (Rec.709).  If the "HDR information" isn't properly mapped down to the smaller colourspace, you end up with output like you're seeing (washed out) or overly dark.

 

 

Exactly this.  Tonemapping can be complicated and while there are several methods in ffmpeg to do it, there isn't a "best way" as each method has strengths and weaknesses (some are better at detail preservation while others are better at preserving colour accuracy, etc).  I'm sure the Emby team will get to it eventually and pick a method to do it (or offer an option), but until then, it's probably best to treat HDR content as "direct play only" in your mind.  If you do have a mix of HDR/non devices, you could always encode an SDR version and store it using Emby's multi-version support so that you'd have a version to play on your non-HDR devices that won't look terrible .

 

That's what I was afraid of. So its a matter of waiting for HDR -> SDR support on the shield tv/google player Emby uses.

 

I think I'll stick with normal blu rays for now.