PVR HDR Auto Switching


I just noticed that when watching 4K (DVB-S2) channels via PVR (TVHeadend 4.2) my TV doesn’t auto switch to HDR and proper color space. You need to manually force both settings in the TV configuration.

I thought that maybe TVHeadend doesn’t support the HDR properly but I found this topic : https://tvheadend.org/issues/5296

Is anyone experiencing this issue?

Did it ever work? Also, 4K doesn’t automatically mean HDR.

I don’t think it ever did. This is more of an bug fix/feature request I guess. Yah, I’m aware of the fact 4K doesn’t always mean HDR but I tested bunch of the live tv channels with HDR support and autoswitch just isn’t there/doesn’t work.

Support for HDR is built into the kernel, so I’m not sure what exactly is going on there. I don’t think that any of our devs have sat TV, and especially sat TV with HDR channels…
Note: If the channels use HLG, that’s not supported.

I tested the 4K channels that are FTA so maybe if any of the devs has DVB-S2 configuration, they could also find some “test” channels on their TVH. As far as I know channels are HDR10, not HLG.

What is your device?

Mecool KIII Pro

Iirc autoswitch requires a refresh rate change. But the stream probably changes HDR/non HDR on the fly

That’s not how it works. When a HDR stream is encountered, the box will switch the TV into HDR mode. Adjusting the color depth requires resolution/refresh rate change, switching HDR on/off doesn’t.

Hmm I checked codec details on my VLC and looks like the channel indeed is in HLG…

Rest of them aren’t currently broadcasting HDR content, just regular BT.709

Nice, mystery solved then :slight_smile:

Ok, let me just refresh this topic - I know its basically digging in the graveyard :slight_smile:

I wanted to ask if there are any plans on detecting HLG (Hybrid-Log Gamma) flag on the PVR signal? The picture itself is fine and live tv channels work fine - the only issue is that you have to manually switch the picture mode in your TV to HDR and BT2020 color range as CE (Kodi) doesn’t detect the HLG flag to tell TV to switch the picture mode automatically.

Would be awesome if CE could detect such flag in the stream and force TV to enable HDR.


HLG from live TV (iptv) works fine for me. Are your streams VP9 or HEVC?

They are HEVC coming from the TVHeadend DVB-T2 FTA channel.

Like I said I need to switch to HDR manually on my TV and it’s even worse because some shows are in HDR and some aren’t so you have to constantly switch back and forth between HDR and SDR while watching the same channel.

Does it switch to HLG if the currently playing show is in HLG or not?
This sort of thing should happen automatically, the decoder extracts metadata directly from the stream, as long as it is available.
Since I don’t have any way to reproduce the issue, I’m not sure what to event look for.

Try to record short (few minutes) clips where the clip starts with HLG and ends in SDR, one that starts in SDR and ends in HLG and one that is only HLG. See if they play correctly from local storage, if not, send them to us and we’ll see if there’s anything we can do to fix it.

The TV does not switch to HLG or HDR at all if the current show is in HLG. I recorded a sample video and tried to play it from local storage and it also didn’t trigger the HDR (HLG) on my TV.

Here is the sample file: 450.37 MB file on MEGA

The file is quite large as its 4K. Also originally it was recorded in TS format but MKVToolNix exports MKV.

Let me just say that this only happens with Live TV. When watching movies or other TV shows from local storage in non HLG format, the TV does properly switch to HDR.

Let me know if you need any other sample file.

I just tested your sample, and on my TV, HLG is triggered just fine.
I’m not sure if that segment contained both HLG and non-HLG parts, though, as the TV did stay in HLG all the time.
Make sure that you have the latest Matrix version, and try to play the following youtube video, it should play in HLG HDR. If it doesn’t, maybe your TV or AVR/whever it is that may be between the TV and the box doesn’t support HLG. Please post dispinfo output.
[4K HDR HLG] Sony A7sIII test #47 - https://www.youtube.com/watch?v=ta5aFjNxyV0

Oh I’m not on Matrix, I’m using 9.2.7 legacy on S912 KIII Pro. It supports the HLG but maybe the old kernel doesn’t :frowning:

And that YouTube video also doesn’t trigger HDR/HLG.

This is my dispinfo - http://ix.io/3qA1

Of course, 3.14 kernel doesn’t support HLG.

Mystery solved then. I’m out of luck… @TheCoolest thank you so much for looking into this! :slight_smile:

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