The MOQ ecosystem has two container format philosophies for packaging media.
LOC - Low Overhead Container
moq-loc (draft-ietf-moq-loc-02)
- Minimal encapsulation overhead
- WebCodecs-native: aligns directly with browser APIs
- Optimized for real-time and interactive use (<500ms latency)
- Codec-agnostic via metadata properties
- No existing tooling ecosystem
CMAF - Common Media Application Format
Used via moq-cmsf (draft-ietf-moq-cmsf-00)
- Industry standard for OTT streaming (HLS/DASH)
- Broad tooling support: encoders, packagers, players
- Higher overhead per object
- Well-understood by CDN operators
- Supports DRM workflows
The Bridge: Compressed MP4
luke-curley proposed draft-lcurley-compressed-mp4-00 (2026-03-18) as a way to compress CMAF containers, potentially bridging the gap between LOC’s low overhead and CMAF’s compatibility. His comment: “it’s kinda gross, but maybe it’s enough to bridge the gap between LOC and CMAF so we don’t have a container split based on the use-case.”
Media Interop (Concrete Wire Format)
moq-media-interop (draft-cenzano-moq-media-interop-03, individual, expires 2026-04-23)
- Defines a concrete media wire format on top of LOC
- Covers H.264 video (AVCC), Opus audio, AAC-LC audio, and UTF-8 text
- Uses MOQT extension headers for metadata (PTS, DTS, timebase, wallclock)
- Supports mid-stream encoding parameter changes
- Authored by Jorge Cenzano-Ferret and alan-frindell at Meta
- Documents the wire format used by moxygen
Current State
Both approaches coexist within moq-msf:
- MSF supports LOC-packaged media natively
- CMSF extends MSF with CMAF packaging support
- The community has not converged on one approach
Which to Use?
| Use Case | Recommended |
|---|---|
| Real-time conferencing | LOC |
| Live interactive streaming | LOC |
| OTT broadcast-style | CMAF via CMSF |
| Existing CMAF pipeline | CMAF via CMSF |
| WebCodecs-first browser app | LOC |
Related
- moq-loc - LOC specification
- moq-cmsf - CMAF via MSF
- moq-media-interop - Concrete wire format for LOC media
- moq-msf - Parent streaming format
- adaptive-bitrate - ABR works with both approaches