every.channel/evolution/proposals/ECP-0034-raw-cmaf-output.md

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.