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Applications and Real-Time Media Over QUIC MoQ MoQTransport WARP This document specifies the WARP Streaming Format, designed to operate on Media Over QUIC Transport. About This Document The latest revision of this draft can be found at . Status information for this document may be found at . Discussion of this document takes place on the Media Over QUIC Working Group mailing list (), which is archived at . Subscribe at . Source for this draft and an issue tracker can be found at .

Introduction WARP Streaming Format (WARP) is a media format designed to deliver CMAF compliant media content over Media Over QUIC Transport (MOQT) . WARP works by fragmenting the bitstream into objects that can be independently transmitted. WARP leverages a simple prioritization strategy of assigning newer content a higher delivery order, allowing intermediaries to drop older data, and video over audio, in the face of congestion. Either complete Groups of Pictures (GOPS) or individual frames are mapped to MoQTransport Objects. WARP is targeted at interactive levels of live latency. This document describes version 1 of the streaming format.

Conventions and Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here. This document uses the conventions detailed in Section 1.3 of when describing the binary encoding.

Media packaging WARP delivers CMAF-packaged media bitstreams. This specification references to define how CMAF packaged bitstreams are mapped to groups and objects. Both CMAF Object mappings Section 4 are supported and a content producer may use either. To identify to consumers which object mapping mode is being used for a given Track, a new track field is defined as per table 1.

Field	Name	Required	Location	JSON type	Definition
WARP packaging mode	warp-packaging	yes	RT	String	See

Packaging mode The packaging mode value is defined by Table 2.

warp-packing field value	Condition	Explanation
frag-per-group	4.1 is active	Each CMAF Fragment is placed in a single MOQT Object and there is one MOQT Object per MOQT Group
chunk-per-object	4.2 is active	Each CMAF chunk is placed in a MOQT Object and there is one MOQT Group per CMAF Fragment

Time-alignment WARP Tracks MAY be time-aligned. Those that are, are subject to the following requirements:

• Time-aligned tracks MUST be advertised in the catalog as belonging to a common render group.
• The presentation time of the first media sample contained within the first MOQT Object of each equally numbered MOQT Group MUST be identical.

A consequence of this restriction is that a WARP receiver SHOULD be able to cleanly switch between time-aligned media tracks at group boundaries.

Content protection and encryption The catalog and media object payloads MAY be encrypted. Common Encryption with 'cbcs' mode (AES CBC with pattern encryption) is the RECOMMENDED encryption method. ToDo - details of how keys are exchanged and license servers signaled. May be best to extend catalog spec to allow the specification of content protection schema, along with any pssh or protection initialization data.

Catalog WARP uses the Common Catalog Format {[COMMON-CATALOG-FORMAT}} to describe the content being produced by a publisher. Per Sect 5.1 of , WARP registers an entry in the "MoQ Streaming Format Type" table. The type value is 0x001, the name is "WARP Streaming Format" and the RFC is XXX. Every WARP catalog MUST declare a streaming format type (See Sect 3.2.1 of ) value of 1. Every WARP catalog MUST declare a streaming format version (See Sect 3.2.1 of ) corresponding to the version of this document. The catalog track MUST have a track name of "catalog". A catalog object MAY be independent of other catalog objects or it MAY represent a delta update of a prior catalog object. The first catalog object published within a new group MUST be independent. A catalog object SHOULD only be published only when the availability of tracks changes. Each catalog update MUST be mapped to a discreet moq-transport object.

Media transmission The MOQT Groups and MOQT Objects need to be mapped to moq-transport Streams. Irrespective of the in place, each MOQT Object MUST be mapped to a new moq-transport Stream.

Workflow A WARP publisher MUST publish a catalog track object before publishing any media track objects. At the completion of a session, a publisher MUST publish a catalog update that removes all currently active tracks. This action SHOULD be interpreted by receivers to mean that the publish session is complete.

Security Considerations ToDo

IANA Considerations This document creates a new entry in the "MoQ Streaming Format" Registry (see Sect 8). The type value is 0x001, the name is "WARP Streaming Format" and the RFC is XXX.

Normative References Twitch Meta Cisco Google This document defines the core behavior for Media over QUIC Transport (MOQT), a media transport protocol over QUIC. MOQT allows a producer of media to publish data and have it consumed via subscription by a multiplicity of endpoints. It supports intermediate content distribution networks and is designed for high scale and low latency distribution. Akamai Packaging CMAF content for use with moq-transport. This document defines the core of the QUIC transport protocol. QUIC provides applications with flow-controlled streams for structured communication, low-latency connection establishment, and network path migration. QUIC includes security measures that ensure confidentiality, integrity, and availability in a range of deployment circumstances. Accompanying documents describe the integration of TLS for key negotiation, loss detection, and an exemplary congestion control algorithm. In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.

Acknowledgments

• Alan Frindell
• Ali Begen
• Charles Krasic
• Christian Huitema
• Cullen Jennings
• Hang Shi
• James Hurley
• Jordi Cenzano
• Mike English
• the MoQ Workgroup and mailing lists.