The purpose of MSF is to provide an interoperable media streaming format operating over [MoQTransport]. Interoperability implies that:
-
An original publisher can package incoming media content into tracks, prepare a catalog and announce the availability of the content to an MOQT relay. Media content refers to audio and video data, as well as ancillary data such as captions, subtitles, accessibility and other timed-text data.
-
An MOQT relay can process the announcement as well as cache and propagate the tracks, both to other relays or to the final subscriber.
-
A final subscriber can parse the catalog, request tracks, decode and render the received media data.
MSF is intended to provide a format for delivering commercial media content. To that end, the following features are within scope:
-
Video codecs - all codecs supported by [LOC]
-
Audio codecs - all audio codecs supported by [LOC]
-
Catalog track - describes the availability and characteristics of content produced by the original publisher.
-
Timeline track - describes the relationship between MOQT Group and Object IDs to media time.
-
Token-based authorization and access control
-
Captions + Subtitles - support for [WEBVTT] and [IMSC1] transmission
-
Latency support across multiple regimes (thresholds are informative only and describe the delay between the original publisher placing the content on the wire and the final subscriber rendering it)
-
Real-time - less than 500ms
-
Interactive - between 500ms and 2500ms
-
Standard - above 2500ms
-
VOD latency - content that was previously produced, is no longer live and is available indefinitely.
-
Content encryption
-
ABR between time-synced tracks - subscribers may switch between tracks at different quality levels in order to maximize visual or audio quality under conditions of throughput variability.
-
Capable of delivering interstitial advertising.
-
Logs and analytics management - support for the reporting of client-side QoE and relay delivery actions via publish tracks using [MOQLOG] and [MOQMETRICS].
Initial versions of MSF will prioritize basic features necessary to exercise interoperability across delivery systems. Later versions will add commercially necessary features.