draft-ietf-moq-loc-02 | 19 pages | Expires 2026-03-15
Authors
- Mo Zanaty (Cisco)
- suhas-nandakumar (Cisco)
- Peter Thatcher (Microsoft)
Abstract
LOC presents a container format for encoded audio and video media intended primarily for interactive streaming over QUIC. It emphasizes minimal encapsulation overhead and compatibility with WebCodecs standards.
Key Features
- Minimal overhead: Designed for low-latency interactive use cases
- WebCodecs compatible: Aligns with browser WebCodecs API
- Codec agnostic: Metadata properties for both audio and video
- E2E encryption: Supports moq-secure-objects integration
- Extension mechanism: Header extensions for timestamps, video frame marking, audio level
Extensions (draft-02)
LOC uses numbered extensions in the object header:
- Timestamp
- Video Frame Marking (ID=4)
- Audio Level
- Note: Issue #13 - Duplicate extension ID (0x06) for Timestamp and Audio Level
Active Issues (moq-wg/loc)
- #18 - Moving redundant properties in the catalog?
- #17 - Delta compress timestamps
- #16 - Unix epoch + Timescale
- #15 - Ambiguity in Video Frame Marking vi64 encoding
- #14 - WebCodecs issue: fix new avc3/hev1 formats
- #13 - Duplicate extension ID for Timestamp and Audio Level
- #10 - Properties Type collision between moqt-draft17 and loc-01
- #9 - Track Property can’t be authenticated
- #5 - Move LOC header metadata from object header extensions to object payload
Related
- moq-transport - Transport layer
- moq-msf - Streaming format that uses LOC
- moq-cmsf - CMAF variant that also supports LOC
- media-packaging - Comparison with CMAF approach
Design Tension: LOC vs CMAF
LOC represents the “low overhead” approach optimized for interactive/real-time use cases, while moq-cmsf provides CMAF compatibility for traditional OTT streaming. luke-curley has proposed CMAF compression as a potential bridge between the two approaches.