v141 · webrtc

WebRTC Encoded Transform (V2)

This API allows processing of encoded media flowing through an RTCPeerConnection. Chromium shipped an early version of this API in 2020. Since then, the spec has changed and other browsers have shipped the updated version of the spec (Safari in 2022 and Firefox in 2023). This launch refers to the latest spec version and is part of Interop 2025.

concepts

  1. Encoded Transform V2

    WebRTC Encoded Transform V2 — refined streams + writer + metadata exposure. Crypto and ML pipelines can read/write encoded frames with much less ceremony than v1.

  2. E2E Encryption

    The canonical sample-link use case. SFU-routed video where the conferencing provider never sees the key. Worker pipeline laid out + link to the live webrtc-samples demo.

  3. Metadata Mux

    Inject caption ticks, watermark IDs, ML landmarks into the encoded byte stream and strip them on the peer. Frame-locked metadata without a separate datachannel.

  4. Video Watermarker

    Loopback RTCPeerConnection with an RTCRtpScriptTransform that XORs a visible watermark pattern into each video frame's encoded payload. A control panel lets you toggle the watermark, change its opacity seed, and observe frame timestamps in the transform worker log — demonstrating the V2 sender/receiver transform API symmetry.

why it shipped

Latest version of API to allow processing of encoded media in RTCPeerConnections.

references