Media servers need to account for client-side CPU in WebRTC

27 Jan 2026 · 2 min

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1:55

In this presentation, the speaker argues that while SFUs (Selective Forwarding Units) already manage network conditions for WebRTC calls, they must also orchestrate client‑side CPU load. To do this, clients should continuously send CPU telemetry to the server. The SFU can then make intelligent, per‑participant decisions such as switching to lower‑bitrate or different simulcast/SVC layers, applying temporal scalability to reduce frame rate, stopping or rerouting video streams based on layout and context, and renegotiating bitrates. These server‑side actions aim to improve overall media quality by tailoring resource usage to each participant’s device capabilities. The talk concludes by asking the audience to identify the single most valuable piece of client‑side CPU telemetry for the server to act upon.

Chapters

We've spent years optimizing network conditions and adapting dynamically. What we're lacking is the same for the CPU load on the client side. Now, the SFU or media server need to be part of the solution here. It needs to orchestrate all that. Why? Because today the SFU is a kind of a brain to the call. It knows everything or should know everything and can act accordingly in front of each individual user within the call. It does that today quite well for the network. It needs to do the same for the CPU load on the client side. For that, the clients need to send their telemetry to the server. And then what can the SFU do? Well, it can decide to reduce and use a different bitrate, a different simulcast layer or SVC. It can decide to use temporal scalability and reduce the frame rate if it has that capability. It can altogether stop sending or receiving videos from different participants to different participants based on the layouts and the context. And if needed, it can also renegotiate the different bitrates in simulcast or SVC from certain senders so that the receivers can get what they need. This intelligent server-side decision-making process is going to improve and enhance the quality of the media for all participants, each within— with its own specific needs in the call. Scalable, high-quality WebRTC calls doesn't mean only smart clients. It also means smart SFU servers. Now, what key piece of client-side CPU telemetry do you think is most valuable for the media server to act upon? Answer below.