The current Steam beta has a new Remote Play video codec, Pyrowave!
It is available now in Steam beta on macOS and Windows. It's available in Steam beta on Linux if you enable the experimental SteamRT3 Steam Client, available in System Settings. This is coming soon to the Steam Link app for mobile devices.
This is a high bandwidth, low latency video codec created by Hans-Kristian Arntzen, with some unique characteristics that make it an interesting option for Steam Remote Play.
High Bandwidth
This codec uses 5-10 times the amount of bandwidth of other streaming codecs, so you'll want to have your computers connected directly to your router with at least Gigabit ethernet.
Low Latency
This codec uses the GPU to encode and decode frames to achieve extremely low end to end latency with a good network.
Supports YUV 4:4:4 and HDR
This codec has options to encode colors with more precision. HDR is automatically selected if supported by both the host and the client. YUV 4:4:4 takes slightly more bandwidth and processing time, so it's not enabled by default, but can be turned on if you're streaming your desktop or reading text on a 4K display.
Enabling the Codec
Pyrowave isn't enabled by default, but you can turn it on in the Steam Remote Play advanced client settings.
Steam will normally tune the video stream for visual quality. Each frame will have a constant size designed to look good, and the higher your framerate, the higher the bandwidth needed. There is a quality slider which you can use to tune the quality up and down, directly impacting the bandwidth.
If your network has a bandwidth limit, or you want to directly tune it, you can turn off automatic bitrate and set a specific bitrate, in the range of 100 Mbit/s to 500 Mbit/s.
The total latency of your video stream is the time for encode + network + decode + display. You can visualize this by turning on the performance graph in the Remote Play settings while you're streaming.
Because the total latency is the combination of video codec and network latency, your particular setup may or may not benefit from the new codec, but feel free to give it a try and let us know how it works for you!