# 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:
- `ec-node wt-publish` uses `moq-native-ietf` + `moq-transport` + `moq-pub` (fMP4 ingestion) for Cloudflare relay compatibility.

### 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.