Crate moq_lite 

moq-lite: Media over QUIC Transport

moq-lite is designed for real-time live media delivery with sub-second latency at massive scale. This is a simplified subset of the official Media over QUIC (MoQ) transport, focusing on the practical features.

NOTE: While compatible with a subset of the IETF MoQ specification (see ietf::Version), many features are not supported on purpose. Additionally, the IETF standard is immature and up to interpretation, so many implementations are not compatible anyway. I highly highly highly recommend using moq-lite instead of the IETF standard until at least draft-30.

API

The API is built around Producer/Consumer pairs, with the hierarchy:

• Origin: A collection of Broadcasts, produced by one or more Sessions.
• Broadcast: A collection of Tracks, produced by a single publisher.
• Track: A collection of Groups, delivered out-of-order until expired.
• Group: A collection of Frames, delivered in order until cancelled.

To publish media, create:

• Origin::produce to get an OriginProducer and OriginConsumer pair.
• OriginProducer::create_broadcast to create a BroadcastProducer.
• BroadcastProducer::create_track to create a TrackProducer for each track.
• TrackProducer::append_group for each Group of Pictures (GOP) or audio frames.
• GroupProducer::write_frame to write each encoded frame in the group.

To consume media, create:

• Origin::produce to get an OriginProducer and OriginConsumer pair.
• OriginConsumer::announced to discover new BroadcastConsumers as they’re announced.
• BroadcastConsumer::subscribe_track to get a TrackConsumer for a specific track.
• TrackConsumer::next_group to receive the next available group.
• GroupConsumer::read_frame to read each frame in the group.

Advanced Usage

• Use FrameProducer and FrameConsumer for chunked frame writes/reads without allocating entire frames (useful for relaying).
• Use TrackProducer::create_group instead of TrackProducer::append_group to produce groups out-of-order.

Modules

coding

Contains encoding and decoding helpers.

ietf

An implementation of the IETF MoQ specification.

lite

The low-level encoding for the moq-lite specification.

Structs

Broadcast

A collection of media tracks that can be published and subscribed to.

BroadcastConsumer

Subscribe to abitrary broadcast/tracks.

BroadcastProducer

Receive broadcast/track requests and return if we can fulfill them.

Client

A MoQ client session builder.

Frame

A chunk of data with an upfront size.

FrameConsumer

Used to consume a frame’s worth of data in chunks.

FrameProducer

Used to write a frame’s worth of data in chunks.

Group

A group contains a sequence number because they can arrive out of order.

GroupConsumer

Consume a group, frame-by-frame.

GroupProducer

Create a group, frame-by-frame.

Origin

A collection of broadcasts that can be published and subscribed to.

OriginConsumer

Consumes announced broadcasts matching against an optional prefix.

OriginProducer

Announces broadcasts to consumers over the network.

Path

A broadcast path that provides safe prefix matching operations.

Produce

A named tuple of a producer and consumer for convenience.

Server

A MoQ server session builder.

Session

A MoQ transport session, wrapping a WebTransport connection.

TimeOverflow

Timescale

A timestamp representing the presentation time in a given scale. ex. 1000 for milliseconds.

Track

TrackConsumer

A consumer for a track, used to read groups.

TrackProducer

A producer for a track, used to create new groups.

Enums

Error

A list of possible errors that can occur during the session.

Constants

ALPNS

The ALPN strings for supported versions.

VERSIONS

The versions of MoQ that are supported by this implementation.

Traits

AsPath

A trait for types that can be converted to a Path.

SendSyncError

A trait that is Send+Sync except on WASM.

Type Aliases

OriginAnnounce

A broadcast path and its associated consumer, or None if closed.

PathOwned

An owned version of Path with a 'static lifetime.

Result

Time

A timestamp representing the presentation time in milliseconds.