- Streamplace Desktop's rendition settings offer AV1 and 120 fps. With AV1 they also write an H.264 fallback record (at most 1080p, the rate halved to at most 60 fps), keyed after the source so the node lists it second. - WebRTC players drop AV1 from their offer when the stream's source is AV1 and MediaCapabilities says this device won't decode it smoothly, so the node sends the H.264 fallback. - The WebRTC diagnostics report AV1 support; the forced-HLS B-frames check looks at every video track; OBS docs and stream-key guidance allow AV1.