Low Overhead CMAF for Media over QUIC (LOCMAF) rev 00 lands on the IETF Datatracker
This document specifies LOCMAF (Low Overhead CMAF for Media over QUIC), a compact wire format for streaming low-latency CMAF media over the MoQ Transport protocol (MOQT) with per-object overhead comparable to the Low Overhead Container (LOC). LOCMAF carries the CMAF chunk head metadata from a single moof (movie fragment) — as a small set of tagged fields inside one of two LOCMAF object kinds, while leaving the sample data (mdat) untouched. In addition, it can carry the optional styp (segment type), prft (producer reference time), any number of emsg (event message) boxes. The first object of each MOQT group carries a full reference; subsequent objects in the same group carry only the differences. The receiver reconstructs CMAF chunks that are semantically equivalent to the sender input, including encryption metadata required by CMAF DRM (Common Encryption) pipelines.
Draft Snapshot
- Draft:
draft-einarsson-moq-locmaf - Revision: 00
- Last updated: 2026-06-02
- Source: IETF Datatracker
Summary
This document specifies LOCMAF (Low Overhead CMAF for Media over QUIC), a compact wire format for streaming low-latency CMAF media over the MoQ Transport protocol (MOQT) with per-object overhead comparable to the Low Overhead Container (LOC). LOCMAF carries the CMAF chunk head metadata from a single moof (movie fragment) — as a small set of tagged fields inside one of two LOCMAF object kinds, while leaving the sample data (mdat) untouched. In addition, it can carry the optional styp (segment type), prft (producer reference time), any number of emsg (event message) boxes. The first object of each MOQT group carries a full reference; subsequent objects in the same group carry only the differences. The receiver reconstructs CMAF chunks that are semantically equivalent to the sender input, including encryption metadata required by CMAF DRM (Common Encryption) pipelines.
Analysis
This draft is directly relevant to the MOQ ecosystem and worth tracking because it reflects current protocol work or adjacent implementation guidance from the IETF process.
Abstract
This document specifies LOCMAF (Low Overhead CMAF for Media over QUIC), a compact wire format for streaming low-latency CMAF media over the MoQ Transport protocol (MOQT) with per-object overhead comparable to the Low Overhead Container (LOC). LOCMAF carries the CMAF chunk head metadata from a single moof (movie fragment) — as a small set of tagged fields inside one of two LOCMAF object kinds, while leaving the sample data (mdat) untouched. In addition, it can carry the optional styp (segment type), prft (producer reference time), any number of emsg (event message) boxes. The first object of each MOQT group carries a full reference; subsequent objects in the same group carry only the differences. The receiver reconstructs CMAF chunks that are semantically equivalent to the sender input, including encryption metadata required by CMAF DRM (Common Encryption) pipelines.