HDR game streaming: what the host and client need

Streamed HDR works only when host, codec and client all carry 10-bit PQ. Which Punktfunk hosts and apps do, and how to check what you got.

You turned HDR on and the stream still looks like SDR. Host, encoder, codec and screen all have to carry 10-bit PQ. Punktfunk checks each link before the first frame: HDR10 when all hold, a clean 8-bit SDR stream when one doesn't.

Hosts

• Windows: nothing to set, with NVENC, AMF, Quick Sync or PyroWave. Vulkan games need the installer's HDR Vulkan layer, on by default.
• Linux with gamescope: install punktfunk-gamescope and let the host start the session. This is the only Linux route to HDR for the Punktfunk apps.
• KDE, GNOME, sway, Hyprland: SDR. Their virtual outputs are 8-bit.

The codec must be HEVC, AV1 or PyroWave. H.264 has no 10-bit path.

Clients

HDR is on by default in every Punktfunk app.

• Linux, Steam Deck: HDR10 where the display offers it, tone-mapped to SDR otherwise.
• Windows: HDR only when Windows HDR is on for the monitor the stream is on; SDR otherwise.
• Mac, iPhone, iPad: HDR only on an HDR-capable screen.
• Apple TV: HDR10 when tvOS Match Content is on.
• Android: HDR is greyed out on a panel without HDR10.

No HDR screen? 10-bit SDR gives smoother gradients, where the host's encoder supports it.

Check it

Set the stats overlay to Detailed: the first line shows HDR, or HDR→SDR when your client tone-maps. On a Linux host, punktfunk-host hdr-probe tests every link.

Every setting is in the HDR docs. Vulkan game says HDR isn't supported? Read this post.