MSF

MSF (MOQT Streaming Format, draft-ietf-moq-msf-00) defines how media content is organized, described, and delivered over the MoQ transport protocol.

While MoQ itself provides the transport primitives — broadcasts, tracks, groups, and frames — MSF defines the standard format for describing what media is available and how to consume it.

import "github.com/qumo-dev/gomoqt/msf"

Catalog

A catalog is a JSON document that describes the complete set of tracks available in a broadcast. Subscribers read the catalog to discover available media before opening individual subscriptions.

A catalog describes:

• Track identities — namespace and name for each track
• Media parameters — codec, bitrate, resolution, sample rate, etc.
• Packaging mode — how media data is packed into MoQ groups and frames (LOC, CMAF, media timeline, event timeline)
• Content roles — video, audio, caption, subtitle, etc.
• Dependencies — which tracks depend on other tracks (e.g., enhancement layers)

Catalogs are delivered as a reserved track (typically named "catalog") within the broadcast, so they can be subscribed to like any other track.

Timeline

MSF defines timeline records that map media timestamps to MoQ group/object locations:

• Media Timeline — maps media presentation timestamps to [groupID, objectID] locations with wallclock times
• Event Timeline — records events indexed by wallclock time, object location, or media time, carrying arbitrary JSON payloads

Broadcast

msf.Broadcast is an optional helper that integrates an MSF catalog with moqt.TrackHandler routing, managing the catalog snapshot and per-track handlers together.