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ECP-0063: Cloudflare MoQ Relay + WebTransport-Only Web Watch

Status: Draft

Decision

Adopt Cloudflare's MoQ relay preview as the default "global" distribution layer and make the web watcher path WebTransport-only.

Concrete changes:

  1. ec-node gains a WebTransport MoQ publisher path that can publish a live CMAF (fMP4) stream to a relay URL (default: https://relay.cloudflare.mediaoverquic.com/).
  2. every.channel (the deployed static site) becomes a real web watcher by embedding a WebTransport-capable MoQ player component (<hang-watch>).
  3. The existing WebRTC/WS bootstrap directory/relay remains temporarily for compatibility, but is treated as deprecated once MoQ/WebTransport is stable.

Motivation

The project goal is one-to-many live streaming at global scale without rebuilding a bespoke stateful SFU stack.

MoQ over WebTransport moves the core system boundary to:

  • publisher produces timed objects (CMAF fragments),
  • relays cache/fanout,
  • subscribers fetch via a single WebTransport session.

This aligns the "global watcher" story with an infrastructure-native model rather than point-to-point rendezvous.

Scope

In scope for this ECP:

  • "Watch from the web" using WebTransport to a MoQ relay.
  • "Publish from a node" to the relay, using ffmpeg to create fMP4 fragments.
  • A shareable link format for every.channel to open a specific relay + broadcast name.

Out of scope (explicitly deferred):

  • Global discovery/index of broadcasts.
  • Manifest signing / Merkle availability / anti-junk (separate ECPs already exist).
  • Safari support guarantees (implement anyway; provide guidance/flag notes).
  • Multi-variant ladders and ABR (follow-on ECP once single-variant publish/watch works end-to-end).

Technical Notes

Relay default

Default relay endpoint is:

  • https://relay.cloudflare.mediaoverquic.com/

Nodes may override via CLI flags for self-hosted relays or future Cloudflare relay endpoints.

Web player

Use the @kixelated/hang web component:

  • <hang-watch url="..." name="..." controls>

This is WebTransport + WebCodecs based, and is expected to interoperate with Cloudflare's current relay preview.

Transport compatibility

Cloudflare's public relay currently implements a subset of the IETF MoQ Transport draft-07 and may not interoperate with newer draft implementations.

Implementation choice:

  • Cloudflare's relay preview currently does not support ANNOUNCE (namespace-style publishing). ec-node wt-publish uses the moq-lite publish model via moq-native and moq-mux (fMP4 ingestion) for Cloudflare relay compatibility.
  • On NixOS deployments, we disable moq-native's WebSocket fallback (MOQ_CLIENT_WEBSOCKET_ENABLED=false) to ensure WebTransport (QUIC) is used. This avoids the WebSocket path occasionally "winning" the race and then failing MoQ negotiation against the Cloudflare relay, causing rapid reconnect loops.

Share link

Web share link:

  • https://every.channel/watch?url=<relay-url>&name=<broadcast-name>

Rollout / Reversibility

  • Keep existing /api/* bootstrap endpoints during migration.
  • Make the web site prefer MoQ/WebTransport; keep legacy paths hidden behind "advanced" until removed.
  • Reversible by switching the deployed assets back to the previous UI build, and/or pointing users at the legacy paths.