WARP Streaming Format
draft-law-moq-warpstreamingformat-03
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Will Law , Luke Curley , Victor Vasiliev , Suhas Nandakumar , Kirill Pugin | ||
| Last updated | 2024-10-15 | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
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draft-law-moq-warpstreamingformat-03
Media Over QUIC W. Law
Internet-Draft Akamai
Intended status: Informational L. Curley
Expires: 19 April 2025 Twitch
V. Vasiliev
Google
S. Nandakumar
Cisco
K. Pugin
Meta
16 October 2024
WARP Streaming Format
draft-law-moq-warpstreamingformat-03
Abstract
This document specifies the WARP Streaming Format, designed to
operate on Media Over QUIC Transport.
About This Document
This note is to be removed before publishing as an RFC.
The latest revision of this draft can be found at
https://wilaw.github.io/MoQ/draft-law-moq-warpmedia.html. Status
information for this document may be found at
https://datatracker.ietf.org/doc/draft-law-moq-warpstreamingformat/.
Discussion of this document takes place on the Media Over QUIC
Working Group mailing list (mailto:moq@ietf.org), which is archived
at https://mailarchive.ietf.org/arch/browse/moq/. Subscribe at
https://www.ietf.org/mailman/listinfo/moq/.
Source for this draft and an issue tracker can be found at
https://github.com/wilaw/MoQ.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 19 April 2025.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 4
3. Media packaging . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. LOC packaging . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Time-alignment . . . . . . . . . . . . . . . . . . . . . 4
3.3. Content protection and encryption . . . . . . . . . . . . 5
4. Catalog . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1. Catalog Fields . . . . . . . . . . . . . . . . . . . . . 5
4.2. WARP version . . . . . . . . . . . . . . . . . . . . . . 7
4.2.1. Supports delta updates . . . . . . . . . . . . . . . 7
4.2.2. Tracks . . . . . . . . . . . . . . . . . . . . . . . 7
4.2.3. Tracks object . . . . . . . . . . . . . . . . . . . . 8
4.2.4. Track namespace . . . . . . . . . . . . . . . . . . . 8
4.2.5. Track name . . . . . . . . . . . . . . . . . . . . . 8
4.2.6. Packaging . . . . . . . . . . . . . . . . . . . . . . 8
4.2.7. Track label . . . . . . . . . . . . . . . . . . . . . 8
4.2.8. Render group . . . . . . . . . . . . . . . . . . . . 9
4.2.9. Alternate group . . . . . . . . . . . . . . . . . . . 9
4.2.10. Initialization data . . . . . . . . . . . . . . . . . 9
4.2.11. Dependencies . . . . . . . . . . . . . . . . . . . . 9
4.2.12. Temporal ID . . . . . . . . . . . . . . . . . . . . . 9
4.2.13. Spatial ID . . . . . . . . . . . . . . . . . . . . . 10
4.2.14. Codec . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.15. Mimetype . . . . . . . . . . . . . . . . . . . . . . 10
4.2.16. Framerate . . . . . . . . . . . . . . . . . . . . . . 10
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4.2.17. Bitrate . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.18. Width . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.19. Height . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.20. Audio sample rate . . . . . . . . . . . . . . . . . . 11
4.2.21. Channel configuration . . . . . . . . . . . . . . . . 11
4.2.22. Display width . . . . . . . . . . . . . . . . . . . . 11
4.2.23. Display height . . . . . . . . . . . . . . . . . . . 11
4.2.24. Language . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Catalog Patch . . . . . . . . . . . . . . . . . . . . . . 11
4.4. Catalog Examples . . . . . . . . . . . . . . . . . . . . 12
4.4.1. Time-aligned Audio/Video Tracks with single
quality . . . . . . . . . . . . . . . . . . . . . . . 12
4.4.2. Simulcast video tracks - 3 alternate qualities along
with audio . . . . . . . . . . . . . . . . . . . . . 13
4.4.3. SVC video tracks with 2 spatial and 2 temporal
qualities . . . . . . . . . . . . . . . . . . . . . . 14
4.4.4. Patch update adding a track . . . . . . . . . . . . . 16
4.4.5. Patch update removing a track . . . . . . . . . . . . 17
4.4.6. Patch update removing all tracks and terminating the
broadcast . . . . . . . . . . . . . . . . . . . . . . 17
4.4.7. Time-aligned Audio/Video Tracks with custom field
values . . . . . . . . . . . . . . . . . . . . . . . 17
5. Media transmission . . . . . . . . . . . . . . . . . . . . . 18
6. Timeline track . . . . . . . . . . . . . . . . . . . . . . . 18
6.1. Timeline track payload . . . . . . . . . . . . . . . . . 19
6.2. Timeline Catalog requirements . . . . . . . . . . . . . . 19
6.3. Timeline track updating. . . . . . . . . . . . . . . . . 19
7. Workflow . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
10. Normative References . . . . . . . . . . . . . . . . . . . . 20
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction
WARP Streaming Format (WARP) is a media format designed to deliver
LOC [LOC] compliant media content over Media Over QUIC Transport
(MOQT) [MoQTransport]. WARP works by fragmenting the bitstream into
objects that can be independently transmitted. WARP leverages a
catalog format to describe the output of the original publisher.
WARP specifies how content should be packaged and signaled, defines
how the catalog communicates the content, specifies prioritization
strategies for real-time and workflows for beginning and terminating
broadcasts. WARP also details how end-subscribers may perform
adaptive bitrate switching. WARP is targeted at real-time and
interactive levels of live latency.
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This document describes version 1 of the streaming format.
2. 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 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
This document uses the conventions detailed in Section 1.3 of
[RFC9000] when describing the binary encoding.
3. Media packaging
WARP delivers LOC [LOC] packaged media bitstreams.
3.1. LOC packaging
This specification references Low Overhead Container (LOC) [LOC] to
define how audio and video content is packaged. With this packaging
mode, each EncodedAudioChunk or EncodedVideoChunk sample is placed in
a separate MOQT Object. Samples that belong to the same Group of
Pictures (GOP) MUST be placed within the same MOQT Group.
Table 2 provides values for the catalog "packaging" field with LOC
packaging.
+=============+================+==================================+
| Packaging | Condition | Explanation |
| field value | | |
+=============+================+==================================+
| loc | [LOC] packagin | Each EncodedAudioChunk or |
| | is active | EncodedVideoChunk sample is |
| | | placed in a separate MOQT Object |
+-------------+----------------+----------------------------------+
Table 1
3.2. 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.
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* 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.
3.3. Content protection and encryption
ToDo - content protection for LOC-packaged content.
4. Catalog
A Catalog is a MOQT Track that provides information about the other
tracks being produced by a WARP publisher. A Catalog is used by WARP
publishers for advertising their output and for subscribers in
consuming that output. The payload of the Catalog object is opaque
to Relays and can be end-to-end encrypted. The Catalog provides the
names and namespaces of the tracks being produced, along with the
relationship between tracks, properties of the tracks that consumers
may use for selection and any relevant initialization data.
The catalog track MUST have a case-sensitive 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 MOQT Object.
4.1. Catalog Fields
A catalog is a JSON [JSON] document, comprised of a series of
mandatory and optional fields. At a minimum, a catalog MUST provide
all mandatory fields and a 'tracks' field. A producer MAY add
additional fields to the ones described in this draft. Custom field
names MUST NOT collide with field names described in this draft. The
order of field names within the JSON document is not important.
A parser MUST ignore fields it does not understand.
Table 1 provides an overview of all fields defined by this document.
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+========================+======================+================+
| Field | Name | Definition |
+========================+======================+================+
| WARP version | version | Section 4.2 |
+------------------------+----------------------+----------------+
| Supports delta updates | supportsDeltaUpdates | Section 4.2.1 |
+------------------------+----------------------+----------------+
| Tracks | tracks | Section 4.2.2 |
+------------------------+----------------------+----------------+
| Track namespace | namespace | Section 4.2.4 |
+------------------------+----------------------+----------------+
| Track name | name | Section 4.2.5 |
+------------------------+----------------------+----------------+
| Packaging | packaging | Section 4.2.6 |
+------------------------+----------------------+----------------+
| Track label | label | Section 4.2.7 |
+------------------------+----------------------+----------------+
| Render group | renderGroup | Section 4.2.8 |
+------------------------+----------------------+----------------+
| Alternate group | altGroup | Section 4.2.9 |
+------------------------+----------------------+----------------+
| Initialization data | initData | Section 4.2.10 |
+------------------------+----------------------+----------------+
| Dependencies | depends | Section 4.2.11 |
+------------------------+----------------------+----------------+
| Temporal ID | temporalId | Section 4.2.12 |
+------------------------+----------------------+----------------+
| Spatial ID | spatialId | Section 4.2.13 |
+------------------------+----------------------+----------------+
| Codec | codec | Section 4.2.14 |
+------------------------+----------------------+----------------+
| Mime type | mimeType | Section 4.2.15 |
+------------------------+----------------------+----------------+
| Framerate | framerate | Section 4.2.16 |
+------------------------+----------------------+----------------+
| Bitrate | bitrate | Section 4.2.17 |
+------------------------+----------------------+----------------+
| Width | width | Section 4.2.18 |
+------------------------+----------------------+----------------+
| Height | height | Section 4.2.19 |
+------------------------+----------------------+----------------+
| Audio sample rate | samplerate | Section 4.2.20 |
+------------------------+----------------------+----------------+
| Channel configuration | channelConfig | Section 4.2.21 |
+------------------------+----------------------+----------------+
| Display width | displayWidth | Section 4.2.22 |
+------------------------+----------------------+----------------+
| Display height | displayHeight | Section 4.2.23 |
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+------------------------+----------------------+----------------+
| Language | lang | Section 4.2.24 |
+------------------------+----------------------+----------------+
Table 2
Table 2 defines the allowed locations for these fields within the
document
+==========+=================================+
| Location | Allowed locations for the field |
+==========+=================================+
| R | The Root of the JSON object |
+----------+---------------------------------+
| T | Track object |
+----------+---------------------------------+
Table 3
4.2. WARP version
Location: R Required: Yes JSON Type: Number
Specifies the version of WARP referenced by this catalog. There is
no guarantee that future catalog versions are backwards compatible
and field definitions and interpretation may change between versions.
A subscriber MUST NOT attempt to parse a catalog version which it
does not understand.
4.2.1. Supports delta updates
Location: R Required: Optional JSON Type: Boolean
A boolean that if true indicates that the publisher MAY issue
incremental (delta) updates - see Section 4.3. If false or absent,
then the publisher gaurantees that they will NOT issue any
incremental updates and that any future updates to the catalog will
be independent. The default value is false. This field MUST be
present if its value is true, but may be omitted if the value is
false.
4.2.2. Tracks
Location: R Required: Yes JSON Type: Array
An array of track objects Section 4.2.3.
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4.2.3. Tracks object
A track object is a collection of fields whose location is specified
'T' in Table 2.
4.2.4. Track namespace
Location: TFC Required: Optional JSON Type: String
The name space under which the track name is defined. See section
2.3 of [MoQTransport]. The track namespace is optional. If it is
not declared within a track, then each track MUST inherit the
namespace of the catalog track. A namespace declared in a track
object overwrites any inherited name space.
4.2.5. Track name
Location: T Required: Yes JSON Type: String
A string defining the name of the track. See section 2.3 of
[MoQTransport]. Within the catalog, track names MUST be unique per
namespace.
4.2.6. Packaging
Location: T Required: Yes JSON Type: String
A string defining the type of payload encapsulation. Allowed values
are strings as defined in Table 3.
Table 3: Allowed packaging values
+======+=======+==============+
| Name | Value | Draft |
+======+=======+==============+
| LOC | "loc" | See RFC XXXX |
+------+-------+--------------+
Table 4
4.2.7. Track label
Location: TF Required: Optional JSON Type: String
A string defining a human-readable label for the track. Examples
might be "Overhead camera view" or "Deutscher Kommentar". Note that
the [JSON] spec requires UTF-8 support by decoders.
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4.2.8. Render group
Location: TF Required: Optional JSON Type: Number
An integer specifying a group of tracks which are designed to be
rendered together. Tracks with the same group number SHOULD be
rendered simultaneously, are usually time-aligned and are designed to
accompany one another. A common example would be tying together
audio and video tracks.
4.2.9. Alternate group
Location: TF Required: Optional JSON Type: Number
An integer specifying a group of tracks which are alternate versions
of one-another. Alternate tracks represent the same media content,
but differ in their selection properties. Alternate tracks SHOULD
have matching framerate Section 4.2.16 and media time sequences. A
subscriber typically subscribes to one track from a set of tracks
specifying the same alternate group number. A common example would
be a set video tracks of the same content offered in alternate
bitrates.
4.2.10. Initialization data
Location: TF Required: Optional JSON Type: String
A string holding Base64 [BASE64] encoded initialization data for the
track.
4.2.11. Dependencies
Location: T Required: Optional JSON Type: Array
Certain tracks may depend on other tracks for decoding. Dependencies
holds an array of track names Section 4.2.5 on which the current
track is dependent. Since only the track name is signaled, the
namespace of the dependencies is assumed to match that of the track
declaring the dependencies.
4.2.12. Temporal ID
Location: T Required: Optional JSON Type: Number
A number identifying the temporal layer/sub-layer encoding of the
track, starting with 0 for the base layer, and increasing with higher
temporal fidelity.
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4.2.13. Spatial ID
Location: T Required: Optional JSON Type: Number
A number identifying the spatial layer encoding of the track,
starting with 0 for the base layer, and increasing with higher
fidelity.
4.2.14. Codec
Location: T Required: Optional JSON Type: String
A string defining the codec used to encode the track. For LOC
packaged content, the string codec registrations are defined in Sect
3 and Section 4 of [WEBCODECS-CODEC-REGISTRY].
4.2.15. Mimetype
Location: T Required: Optional JSON Type: String
A string defining the mime type [MIME] of the track.
4.2.16. Framerate
Location: T Required: Optional JSON Type: Number
A number defining the video framerate of the track, expressed as
frames per second.
4.2.17. Bitrate
Location: T Required: Optional JSON Type: Number
A number defining the bitrate of track, expressed in bits per second.
4.2.18. Width
Location: T Required: Optional JSON Type: Number
A number expressing the encoded width of the video frames in pixels.
4.2.19. Height
Location: T Required: Optional JSON Type: Number
A number expressing the encoded height of the video frames in pixels.
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4.2.20. Audio sample rate
Location: T Required: Optional JSON Type: Number
The number of audio frame samples per second. This property SHOULD
only accompany audio codecs.
4.2.21. Channel configuration
Location: T Required: Optional JSON Type: String
A string specifying the audio channel configuration. This property
SHOULD only accompany audio codecs. A string is used in order to
provide the flexibility to describe complex channel configurations
for multi-channel and Next Generation Audio schemas.
4.2.22. Display width
Location: T Required: Optional JSON Type: Number
A number expressing the intended display width of the track content
in pixels.
4.2.23. Display height
Location: T Required: Optional JSON Type: Number
A number expressing the intended display height of the track content
in pixels.
4.2.24. Language
Location: T Required: Optional JSON Type: String
A string defining the dominant language of the track. The string
MUST be one of the standard Tags for Identifying Languages as defined
by [LANG].
4.3. Catalog Patch
A catalog update might contain incremental changes. This is a useful
property if many tracks may be initially declared but then there are
small changes to a subset of tracks. The producer can issue a patch
to describe these small changes. Changes are described
incrementally, meaning that a patch can itself modify a prior patch.
Patching leverages JSON PATCH [JSON-PATCH] to modify the catalog.
JSON Patch is a format for expressing a sequence of operations to
apply to a target JSON document.
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The following rules MUST be followed in processing patches:
* The target JSON to be modified is the JSON document described by
the preceding [MoQTransport] Object in the Catalog track, post any
patching that may have been applied to that Object.
* A Catalog Patch is identified by having a single array at the root
level, holding a series of JSON objects, each object representing
a single operation to be applied to the target JSON document.
* Operations are applied sequentially in the order they appear in
the array. Each operation in the sequence is applied to the
target document; the resulting document becomes the target of the
next operation. Evaluation continues until all operations are
successfully applied or until an error condition is encountered.
* Track namespaces and track names may not be changed across patch
updates To change either namespace or name, remove the track and
then add a new track with matching properties and the new
namespace and name.
* Contents of the track selection properties object may not be
varied across updates. To adjust a track selection property, the
track must first be removed and then added with the new selection
properties and a different name.
4.4. Catalog Examples
The following section provides non-normative JSON examples of various
catalogs compliant with this draft.
4.4.1. Time-aligned Audio/Video Tracks with single quality
This example shows catalog for a media producer capable of sending
LOC packaged, time-aligned audio and video tracks.
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{
"version": 1,
"tracks": [
{
"name": "video",
"namespace": "conference.example.com/conference123/alice",
"packaging": "loc",
"renderGroup": 1,
"codec":"av01.0.08M.10.0.110.09",
"width":1920,
"height":1080,
"framerate":30,
"bitrate":1500000
},
{
"name": "audio",
"namespace": "conference.example.com/conference123/alice",
"packaging": "loc",
"renderGroup": 1,
"codec":"opus",
"samplerate":48000,
"channelConfig":"2",
"bitrate":32000
}
]
}
4.4.2. Simulcast video tracks - 3 alternate qualities along with audio
This example shows catalog for a media producer capable of sending 3
time-aligned video tracks for high definition, low definition and
medium definition video qualities, along with an audio track. In
this example the namespace is absent, which infers that each track
must inherit the namespace of the catalog. Additionally this example
shows the presence of the supportsDeltaUpdates flag.
{
"version": 1,
"supportsDeltaUpdates": true,
"tracks":[
{
"name": "hd",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01",
"width":1920,
"height":1080,
"bitrate":5000000,
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"framerate":30,
"altGroup":1
},
{
"name": "md",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01",
"width":720,
"height":640,
"bitrate":3000000,
"framerate":30,
"altGroup":1
},
{
"name": "sd",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01",
"width":192,
"height":144,
"bitrate":500000,
"framerate":30,
"altGroup":1
},
{
"name": "audio",
"renderGroup": 1,
"packaging": "loc",
"codec":"opus",
"samplerate":48000,
"channelConfig":"2",
"bitrate":32000
}
]
}
4.4.3. SVC video tracks with 2 spatial and 2 temporal qualities
This example shows catalog for a media producer capable of sending
scalable video codec with 2 spatial and 2 temporal layers with a
dependency relation as shown below:
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+----------+
+----------->| S1T1 |
| | 1080p30 |
| +----------+
| ^
| |
+----------+ |
| S1TO | |
| 1080p15 | |
+----------+ +-----+----+
^ | SOT1 |
| | 480p30 |
| +----------+
| ^
+----------+ |
| SOTO | |
| 480p15 |---------+
+----------+
The corresponding catalog uses "depends" attribute to express the
track relationships.
{
"version": 1,
"supportsDeltaUpdates": true,
"tracks":[
{
"name": "480p15",
"namespace": "conference.example.com/conference123/alice",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01.0.01M.10.0.110.09",
"width":640,
"height":480,
"bitrate":3000000,
"framerate":15
},
{
"name": "480p30",
"namespace": "conference.example.com/conference123/alice",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01.0.04M.10.0.110.09",
"width":640,
"height":480,
"bitrate":3000000,
"framerate":30,
"depends": ["480p15"]
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},
{
"name": "1080p15",
"namespace": "conference.example.com/conference123/alice",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01.0.05M.10.0.110.09",
"width":1920,
"height":1080,
"bitrate":3000000,
"framerate":15,
"depends":["480p15"]
},
{
"name": "1080p30",
"namespace": "conference.example.com/conference123/alice",
"renderGroup": 1,
"packaging": "loc",
"codec":"av01.0.08M.10.0.110.09",
"width":1920,
"height":1080,
"bitrate":5000000,
"framerate":30,
"depends": ["480p30", "1080p15"]
},
{
"name": "audio",
"namespace": "conference.example.com/conference123/alice",
"renderGroup": 1,
"packaging": "loc",
"codec":"opus",
"samplerate":48000,
"channelConfig":"2",
"bitrate":32000
}
]
}
4.4.4. Patch update adding a track
This example shows catalog for the media producer adding a slide
track to an established video conference.
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[
{
"op": "add",
"path": "/tracks/-",
"value": {
"name": "slides",
"codec": "av01.0.08M.10.0.110.09",
"width": 1920,
"height": 1080,
"framerate": 15,
"bitrate": 750000,
"renderGroup": 1
}
}
]
4.4.5. Patch update removing a track
This example shows patch catalog update for a media producer removing
the track from an established video conference.
[
{ "op": "remove", "path": "/tracks/2"}
]
4.4.6. Patch update removing all tracks and terminating the broadcast
This example shows a patch catalog update for a media producer
removing all tracks and terminating the broadcast.
[
{ "op": "remove", "path": "/tracks/2"},
{ "op": "remove", "path": "/tracks/1"},
{ "op": "remove", "path": "/tracks/0"},
]
4.4.7. Time-aligned Audio/Video Tracks with custom field values
This example shows catalog for a media producer capable of sending
LOC packaged, time-aligned audio and video tracks along with custom
fields in each track description.
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{
"version": 1,
"tracks": [
{
"name": "video",
"namespace": "conference.example.com/conference123/alice",
"packaging": "loc",
"renderGroup": 1,
"codec":"av01.0.08M.10.0.110.09",
"width":1920,
"height":1080,
"framerate":30,
"bitrate":1500000,
"com.example-billing-code": 3201,
"com.example-tier": "premium",
"com.example-debug": "h349835bfkjfg82394d945034jsdfn349fns"
},
{
"name": "audio",
"namespace": "conference.example.com/conference123/alice",
"packaging": "loc",
"renderGroup": 1,
"codec":"opus",
"samplerate":48000,
"channelConfig":"2",
"bitrate":32000
}
]
}
5. Media transmission
The MOQT Groups and MOQT Objects need to be mapped to MOQT Streams.
Irrespective of the Section 3 in place, each MOQT Object MUST be
mapped to a new MOQT Stream.
6. Timeline track
The timeline track provides data about the previously published
groups and their relationship to wallclock time, media time and
associated timed-metadata. Timeline tracks allow players to seek to
precise points behind the live head in a live broadcast, or for
random access in a VOD asset. A timeline track may also be used to
insert events at media times which do not correlate with Object
boundaries. Timeline tracks are optional. Multiple timeline tracks
MAY exist inside a catalog.
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6.1. Timeline track payload
The payload of a timeline track is a UTF-8 encoded CSV text file.
This payload is formatted according to RFC4180 "Common Format and
MIME Type for Comma-Separated Values (CSV)" Files [RFC4180]. The
separator is a comma and each line is separated by a carriage return.
The mime-type of a timeline track MUST be specified as "text/csv" in
the catalog.
Each timeline track begins with a header row of
MEDIA_PTS,GROUP_ID,OBJECT_ID,WALLCLOCK,METADATA. This row defines
the 5 columns of data within each record.
* MEDIA_PTS: a media timestamp rounded to the nearest millisecond.
This entry MUST not be empty. If the Object ID entry is present,
then this value MUST match the media presentation timestamp of the
first media sample in the referenced Object.
* GROUP_ID: the MOQT Group ID. This entry MAY be empty.
* OBJECT_ID: the MOQT Object ID. This entry MAY be empty.
* WALLCLOCK: the wallclock time at which the media was encoded,
expressed as the number of milliseconds that have elapsed since
January 1, 1970 (midnight UTC/GMT). For VOD assets, or if the
wallclock time is not known, the value SHOULD be 0.
* METADATA: a flexible field holding arbitrary string metadata.
This field may be empty. If not empty, it MUST be enclosed in
double quotes. A double-quote appearing inside this field MUST be
escaped by preceding it with another double quote.
6.2. Timeline Catalog requirements
A timeline track MUST carry a 'type' identifier in the Catalog with a
value of "timeline". A timeline track MUST carry a 'dependencies'
attribute which contains an array of all track names to which the
timeline track applies.
6.3. Timeline track updating.
The publisher MUST publish a complete timeline in the first MOQT
Object of each MOQT Group. The publisher MAY publish incremental
updates in the second and subsequent Objects within each GROUP.
Incremental updates only contain timeline events since the last
timeline Object. Group duration SHOULD not exceed 30 seconds.
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7. 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.
8. Security Considerations
ToDo
9. IANA Considerations
This document creates a new entry in the "MoQ Streaming Format"
Registry (see [MoQTransport] Sect 8). The type value is 0x001, the
name is "WARP Streaming Format" and the RFC is XXX.
10. Normative References
[BASE64] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/rfc/rfc4648>.
[CMAFpackaging]
Law, W. and L. Curley, "CMAF Packaging for moq-transport",
Work in Progress, Internet-Draft, draft-wilaw-moq-
cmafpackaging-01, 21 July 2024,
<https://datatracker.ietf.org/doc/html/draft-wilaw-moq-
cmafpackaging-01>.
[JSON] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/rfc/rfc8259>.
[JSON-PATCH]
Bryan, P., Ed. and M. Nottingham, Ed., "JavaScript Object
Notation (JSON) Patch", RFC 6902, DOI 10.17487/RFC6902,
April 2013, <https://www.rfc-editor.org/rfc/rfc6902>.
[LANG] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, <https://www.rfc-editor.org/rfc/rfc5646>.
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[LOC] Zanaty, M., Nandakumar, S., and P. Thatcher, "Low Overhead
Media Container", Work in Progress, Internet-Draft, draft-
mzanaty-moq-loc-03, 4 March 2024,
<https://datatracker.ietf.org/doc/html/draft-mzanaty-moq-
loc-03>.
[MIME] Freed, N., Klensin, J., and T. Hansen, "Media Type
Specifications and Registration Procedures", BCP 13,
RFC 6838, DOI 10.17487/RFC6838, January 2013,
<https://www.rfc-editor.org/rfc/rfc6838>.
[MoQTransport]
Curley, L., Pugin, K., Nandakumar, S., Vasiliev, V., and
I. Swett, "Media over QUIC Transport", Work in Progress,
Internet-Draft, draft-ietf-moq-transport-05, 8 July 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-moq-
transport-05>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[RFC4180] Shafranovich, Y., "Common Format and MIME Type for Comma-
Separated Values (CSV) Files", RFC 4180,
DOI 10.17487/RFC4180, October 2005,
<https://www.rfc-editor.org/rfc/rfc4180>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/rfc/rfc5226>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
[WEBCODECS-CODEC-REGISTRY]
"WebCodecs Codec Registry", September 2024,
<https://www.w3.org/TR/webcodecs-codec-registry/>.
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Acknowledgments
* the MoQ Workgroup and mailing lists.
Authors' Addresses
Will Law
Akamai
Email: wilaw@akamai.com
Luke Curley
Twitch
Email: kixelated@gmail.com
Victor Vasiliev
Google
Email: vasilvv@google.com
Suhas Nandakumar
Cisco
Email: snandaku@cisco.com
Kirill Pugin
Meta
Email: ikir@meta.com
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