Serialization of MoQ Objects to Files
draft-jennings-moq-file-00

moq                                                          C. Jennings
Internet-Draft                                                     Cisco
Intended status: Standards Track                         21 October 2024
Expires: 24 April 2025

                 Serialization of MoQ Objects to Files
                       draft-jennings-moq-file-00

Abstract

   This specification provides a way to save the meta data about each
   MoQ Object in one or more files as well as pointers to other files
   that contain the contents of the object.  Separating of the meta data
   and payload data allow the payload data to remain in files that are
   used for other purposes such as serving HLS/DASH video.  This format
   makes it easier to test and develop caching relays and create test
   data they can serve to client.

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/.

   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 24 April 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Jennings                  Expires 24 April 2025                 [Page 1]
Internet-Draft              Moq Object Files                October 2024

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  JSON Meta Object  . . . . . . . . . . . . . . . . . . . . . .   2
   3.  File Naming . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  MOQT Track DataFile . . . . . . . . . . . . . . . . . . . . .   3
   5.  Playback  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Time Object Example . . . . . . . . . . . . . . . . . . .   4
   7.  IANA  . . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   9.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   This specification defines a way of serializing the MoQ Objects
   defined in [MOQT] into files.  The payload data and the meta data are
   separated into separate files to allow reuse of existing files with
   the payload data.

2.  JSON Meta Object

   The .moq files consist of an array of one or more JSON objects.  Each
   JSON object contains information about the MOQT object as well as
   pointers to the where the original data can be found.

   The follow fields are defined for JSON object:

   *  namesSpace: Array of strings that have a Base64 encoded version of
      the data in each tuple of MOQT Track Namespace.

   *  trackName: string with Base64 encoded version of the MOQT
      TrackName.

   *  objectID: integer corresponding to the MOQT ObjectID

   *  groupID: integer corresponding to the MOQT GroupID

Jennings                  Expires 24 April 2025                 [Page 2]
Internet-Draft              Moq Object Files                October 2024

   *  subGroup: integer corresponding to the MOQT SubGroup

   *  publisherPriority: integer corresponding to the MOQT Object
      publisherPriority

   *  maxCacheDuration: integer corresponding to the MOQT
      maxCacheDuration

   *  publisherDeliveryTimeout: integer corresponding to the MOQT
      publisherDeliveryTimeout

   *  receiveTime: time was created or time original was received
      received by the relay.  This is in milliseconds since the unix
      epoch.

   *  dataFile: string with relative path name to the file that stores
      the MOQT Object, including header and its payload data.

   *  dataOffset: number of bytes into file where objects starts ( 0 is
      first byte of file )

   *  dataLength: number of bytes of data in the object

   Any extension attributes should also be saved using a field name
   formed by the string "ext" then the base 10 integer representation of
   the extension type ID.

3.  File Naming

   It is RECOMMENDED to use a URL encoding version of the FullTrackName
   with a suffix of ".moq" as the file name for the meta file.  In this
   context FullTrackName is concatenation of Track Namespace with the
   TrackName, separated by "/".  Optionally, the filename can be
   extended with information about group as needed.

4.  MOQT Track DataFile

   When saving a whole MOQT Track to a file, a common way to do this
   would be to make one ".dat" file with all the object data and another
   ".moq" file with all the array of JSON object for each MOQT Object.
   An implementation can choose to have one file per MOQT group.  In
   such a case, it does so by creating one metadata (".moq") file and
   one datafile (".dat") containing data for each object in the MOQT
   group.

Jennings                  Expires 24 April 2025                 [Page 3]
Internet-Draft              Moq Object Files                October 2024

5.  Playback

   Some use cases will want to just load a file into the relay as
   quickly as possible.  Other may decide to remade the track name to a
   new track name publish the objects at a rate based on differences of
   the receiveTime of the JSON objects.

6.  Example

   TODO More complete example

6.1.  Time Object Example

   Data file named time1.dat contains:

   {"time":17294570764566}

   Metadata file contains:

[
        {
                "namesSpace": "bW9xOi8vbW9xLXRpbWUuYXJwYS90aW1lLXYxLw=",
                "trackName": "bWFjOjcyOjVjOmYwOjdjOmJmOmIw",
                "objectID": 0,
                "groupID": 123,
                "subGroup": 0,
                "publisherPriority": 0,
                "maxCacheDuration": 3600000,
                "publisherDeliveryTimeout": 60000,
                "receiveTime": 1729457464000,
                "dataFile": "time1.dat",
                "dataOffset": 0,
                "dataLength": 25
        }
]

7.  IANA

   TODO file extension registrations.

8.  Security Considerations

   TODO

9.  Normative References

Jennings                  Expires 24 April 2025                 [Page 4]
Internet-Draft              Moq Object Files                October 2024

   [MOQT]     Curley, L., Pugin, K., Nandakumar, S., Vasiliev, V., and
              I. Swett, "Media over QUIC Transport", Work in Progress,
              Internet-Draft, draft-ietf-moq-transport-06, 19 September
              2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
              moq-transport-06>.

Author's Address

   Cullen Jennings
   Cisco
   Email: fluffy@iii.ca

Jennings                  Expires 24 April 2025                 [Page 5]