# ECP-0034: Raw CMAF Output (CMAF-First, Playlist-Optional)

Status: Draft
Author: Codex
Reviewers: founder@every.channel
Created: 2026-02-07

## Decision

Treat CMAF artifacts (init segment + fMP4 media fragments) as the canonical transport payload for low-latency video in every.channel.

Add a subscriber option to write *raw CMAF* files to disk without generating an HLS playlist:

- `ec-node moq-subscribe --container cmaf --subscribe-init --raw-cmaf`
  - writes `init.mp4`
  - writes `segment_%06d.m4s`

HLS (and any other playlist formats) become optional *views* over those CMAF bytes, generated by a separate component when needed.

## Motivation

- CMAF is the common denominator for modern streaming and is the right level of abstraction for MoQ object transport.
- Keeping the transport canonical at "init + fragments" avoids hard coupling the core to HLS/DASH playlist semantics.
- Determinism experiments should focus on fragment bytes, not playlist formatting.

## Scope

In scope:
- Raw CMAF sink for `ec-node moq-subscribe`.
- Keep the existing HLS writer for local playback workflows.

Out of scope:
- MPEG-DASH support (explicitly not pursued here).
- Browser-native playback pipeline (still expected to use a view layer like HLS/MSE).

## Implementation Notes

- `ec-node` already publishes CMAF init on a dedicated MoQ track (`init`) and publishes segments on the main chunks track.
- `--raw-cmaf` is only valid with `--container cmaf` and errors otherwise.
- Naming is stable and deterministic for tests and downstream proxies.

## Reversibility

- This change is additive and gated behind a flag.
- If we later standardize a manifest-driven playlist format, `--raw-cmaf` can remain as a debug and interoperability mode.

