MOQT Streaming Format (MSF)

draft-ietf-moq-msf-00 | 34 pages | Expires 2026-07-23

Authors

• will-law (Akamai)

Abstract

MSF defines the streaming format for delivering media over moq-transport. It enables delivery of moq-loc-compliant media through bitstream fragmentation into independently transmittable objects. Replaces the earlier draft-ietf-moq-warp.

Key Features

• Video and audio codec support: Compatible with LOC packaging
• Catalog track: Describes content characteristics via catalog-format
• Media and event timeline tracks: Temporal mapping for synchronization
• Latency modes:
  • Real-time: <500ms
  • Interactive: 500-2500ms
  • Standard: >2500ms
• adaptive-bitrate: ABR switching between time-synchronized tracks
• Content encryption: Integration with moq-secure-objects

Structure

MSF defines how media is organized into MOQT tracks:

1. Catalog track - JSON-based description of all available tracks
2. Media tracks - Audio and video encoded with LOC
3. Timeline tracks - Wall clock to media time mapping
4. Event tracks - Timed metadata (SCTE-35, captions, etc.)

Active Issues (moq-wg/msf)

• #153 - initTrack does not work
• #150 - Wall clock is problematic
• #149 - Catalog Mapping to MoQT
• #148 - Media Mapping to MoQT
• #147 - Confusing Media Transmission section
• #146 - Clone and track name collisions
• #145 - Ordering of delta updates
• #144 - Compression for the catalog
• #140 - JSON Merge Patch
• #139 - Required/optional fields per role
• #136 - No mechanism to delta update a track
• #135 - Delta updates are not generic

Recent PRs

• PR #152 (Merged Apr 9) - Clarify MSF URL construction and fragment parameters
• PR #143 (Merged) - Break the monolith table into separate tables and sections
• PR #141 (Merged Apr 9) - Add support for InitTracks
• PR #133 (Open) - Add SCTE-35 support and CEA-608/708 accessibility fields
• PR #124 (Merged Apr 9) - Clarify first object in event and media timeline track
• PR #122 (Open) - Initial text on zapping
• PR #121 (Merged Apr 9) - Pub tracks, logs and metrics
• PR #118 (Merged Apr 13) - Add details of authorization flows

Incomplete Sections

The draft-00 marks several sections as ToDo:

• Content protection details
• Security considerations

Related

• moq-transport - Underlying transport protocol
• moq-loc - Container format used by MSF
• moq-cmsf - CMAF-compliant variant of MSF
• catalog-format - Catalog specification
• media-packaging - Container format comparison

External Links

• GitHub repo
• Datatracker