WebRTC Latency: A Breakdown
· 9 min read
Many robotics companies are interested in very low latency video-streaming from their fielded robots, whether that's for tele-operation, tele-assist, or just monitoring. WebRTC has been setting the standard for low latency streaming but some people have started questioning whether even lower latencies are possible. To answer this, one needs to understand where in the pipeline the latency comes from. This is the question we tackle in this post: we break down the glass-to-glass latency of Transitive's WebRTC streaming pipeline that is used in WebRTC Video, Remote Teleop and other capabilities.
tl;dr
- The vast majority of glass-to-glass latency comes from the camera itself and the USB bus (~100 ms).
- H264 encoding and decoding add around 10 ms each (or less).
- WebRTC only adds around 10 ms of latency for remote streaming.
- The rest is due to static network delay ("ping timing", speed of light).