Media Over QUIC P. Gregoire Internet-Draft Red5 Intended status: Informational G. Simon Expires: 11 February 2027 Synamedia 10 August 2026 MPEG-2 Transport Stream Packaging for Media Over QUIC Transport draft-gregoire-moq-msfts-latest Abstract This document extends the Media Over QUIC Transport (MOQT) Streaming Format (MSF) catalog by defining the "m2ts" packaging value for carrying MPEG-2 Transport Stream and M2TS source packets over MOQT. It defines catalog-extension fields for transport-stream track description and specifies receiver behavior for joining, switching, and validating packetized streams. 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://mondain.github.io/msfts/draft-gregoire-moq-msfts.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-gregoire-moq-msfts/. 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/mondain/msfts. 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 11 February 2027. Copyright Notice Copyright (c) 2026 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/ 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. MSF Extension 3. Conventions and Definitions 4. Scope 5. Media Packaging 5.1. Object Payload Format 5.2. Object Boundaries 5.3. Group Numbering 5.4. Packetization 5.5. Source Handling and Carriage Modes 5.5.1. Unmodified Carriage 5.5.2. Modified Carriage 5.5.3. Modified ES-Level Carriage 5.6. PCR and Timing 5.7. Splice Signaling 6. Catalog 6.1. Track Object Fields 6.2. M2TS Packet Size 6.3. M2TS Modified 6.4. M2TS Packets per Object 6.5. M2TS Program Number 6.6. M2TS PMT PID 6.7. M2TS PCR PID 6.8. M2TS PSI Interval 6.9. M2TS Mux Rate 6.10. M2TS SI PIDs 6.11. M2TS Random Access 6.12. M2TS Timestamp Mode 6.13. M2TS SCTE-35 PID 6.14. M2TS ES PID 6.15. M2TS MPTS 6.16. Use of MSF Initialization Data 7. Catalog Examples 7.1. Live 188-octet Transport Stream 7.2. Live 192-octet M2TS Source Packets 7.3. VOD Transport Stream 7.4. Multi-Program Source - Per-Program Tracks 7.5. Transparent MPTS Carriage 7.6. ABR Alternate Renditions - Two Bitrate Tracks 7.7. ES-Level Tracks - Per-Elementary-Stream Publishing 8. Subscriber Processing 9. Switching and Alternate Renditions 10. Content Protection 11. Authorization 12. Security Considerations 13. IANA Considerations 14. References 14.1. Normative References 14.2. Informative References Appendix A. Acknowledgments Authors' Addresses 1. Introduction Media Over QUIC Transport (MOQT) [MOQTransport] delivers named tracks as ordered groups of objects. The MOQT Streaming Format (MSF) [MSF] defines a catalog model and common streaming conventions for describing tracks delivered over MOQT. This document extends the MSF catalog with the "m2ts" packaging value for carrying MPEG-2 Transport Stream packets as defined by [ISO138181] and M2TS source packets that prefix each transport-stream packet with a four-octet source-packet timestamp. The format is intended for publishers that already produce packetized MPEG-2 Transport Stream output, including contribution feeds, broadcast workflows, and systems that currently segment transport streams for HTTP-based delivery. It does not define a new elementary stream container. Instead, it preserves the packet stream and maps consecutive source packets into MOQT Objects. This document describes version 1 of the packaging format. 2. MSF Extension All specifications, requirements, and terminology defined in [MSF] apply to implementations of this extension unless explicitly noted otherwise in this document. This document does not use the LOC packaging defined in [MSF]. MSF requirements that are conditioned on packaging: loc do not apply to m2ts-packaged tracks; equivalent behavior for m2ts tracks is defined in this document. This document is an extension of the catalog defined by the revision of [MSF] identified in the normative references. The catalog structure, common fields, and catalog processing rules are inherited from that revision of MSF. This document defines only the m2ts packaging value and the fields and processing rules specific to that packaging. The catalog version field identifies the referenced MSF revision and does not identify version 1 of the MSFTS packaging format described in Section 1. Catalogs conforming to this document MUST use the version value specified by the referenced revision of MSF. 3. 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. The following terms are used throughout this document: TS packet: A 188-octet MPEG-2 Transport Stream packet as defined by [ISO138181]. M2TS source packet: A 192-octet packet consisting of a four-octet source-packet timestamp followed by a 188-octet TS packet. Source packet: Either a TS packet or an M2TS source packet. The source-packet size is signaled by the catalog. Access unit: A coded audio, video, or metadata unit carried by the MPEG-2 Transport Stream. Random access point: A point in the packet stream at which a receiver can begin decoding after receiving the applicable transport-stream tables and decoder initialization. Single-program transport stream: A transport stream whose Program Association Table (PAT) lists exactly one program. Multi-program transport stream: A transport stream whose Program Association Table lists two or more programs. 4. Scope This specification defines: * The "m2ts" packaging value for use in an MSF catalog. * The mapping of consecutive TS or M2TS source packets into MOQT Objects. * Catalog fields that describe packet size, program selection, packetization, timing, and joining behavior. * Receiver processing rules for validating object payloads and reconstructing the packet stream. This specification does not define: * New MPEG-2 Transport Stream syntax. * New audio, video, metadata, or subtitle codec signaling inside the transport stream. * A replacement for Program Association Table, Program Map Table (PMT), Program Clock Reference (PCR), Presentation Time Stamp (PTS), Decoding Time Stamp (DTS), continuity counter, or scrambling semantics defined by [ISO138181]. * A mandatory Adaptive Bitrate (ABR) switching model across separately encoded transport streams. * A key management protocol. 5. Media Packaging An m2ts-packaged MOQT Track carries a single ordered packet stream. Each MOQT Object payload is a concatenation of one or more whole source packets. The publisher MUST NOT split a source packet across MOQT Objects. When this packaging mode is used for a track, the MSF catalog packaging field MUST be present and MUST be populated with the value "m2ts". 5.1. Object Payload Format The payload of each media Object is: +===============+===============+=====+===============+ | source packet | source packet | ... | source packet | +===============+===============+=====+===============+ The packet size is signaled by m2tsPacketSize (Section 6.2). The payload length of every media Object on an m2ts track MUST be an integer multiple of m2tsPacketSize. If m2tsPacketSize is 188, every source packet MUST begin with the MPEG-2 TS sync byte 0x47. If m2tsPacketSize is 192, the TS packet begins four octets after the start of each source packet and the octet at that position MUST be 0x47. A receiver MUST treat a packet that fails this validation as invalid media data for that track. The source packets from received Objects are concatenated in ascending Group ID and Object ID order to reconstruct the packet stream. A subscriber that skips or fails to receive an Object MUST consider the reconstructed packet stream discontinuous at that point until it reaches a subsequent random access point. 5.2. Object Boundaries Object boundaries are packaging boundaries and do not change MPEG-2 Transport Stream semantics. Continuity counters, adaptation fields, PCR, PTS, DTS, Program Specific Information (PSI), and other transport-stream syntax remain inside the source packets. When m2tsModified (Section 6.3) is false, a publisher MUST NOT modify the continuity counter of any source packet and MUST NOT remap packet identifiers. The modifications permitted when m2tsModified is true are defined in Section 5.5. A publisher SHOULD place an independently usable random access point at the first media Object of each MOQT Group. For single-program video tracks, this normally means that the Group begins at or before the transport-stream packets carrying a random access point and includes the PAT and PMT packets required for program demultiplexing. Codec-level initialization data is carried inside the elementary stream packets of the first video access unit and is therefore present whenever a random access point is included. When m2tsRandomAccess (Section 6.11) is true, the first media Object in every Group MUST provide a valid random access starting point for the Group. 5.3. Group Numbering For live streams, publishers SHOULD start a new MOQT Group at each point where the Group content is independently decodable without reference to prior Groups. For video, a valid Group start is any intra-coded access point at which all decoder references needed by that Group are present within the Group itself. Instantaneous Decoder Refresh (IDR) frames always satisfy this condition. A Clean Random Access (CRA) frame MAY serve as a Group start only if no subsequent Random Access Skipped Leading (RASL) pictures in that Group reference frames from a prior Group. Publishers are not required to start a new Group at every intra-coded access point: a CRA whose following RASL pictures reference only frames present earlier in the same Group may remain interior to that Group. The Object ID MUST increase by one for each Object within a Group unless MOQT delivery semantics permit gaps that are explicitly intended by the publisher. For video-on-demand (VOD) streams, Group ID and Object ID assignment SHOULD be stable for a given asset so that relays and subscribers can cache and request repeatable ranges. 5.4. Packetization Publishers SHOULD choose Object sizes that are large enough to amortize MOQT object overhead and small enough to avoid excessive head-of-line delay at the application layer. The number of source packets per Object can vary, but a publisher SHOULD keep it stable within a track unless adapting to network or encoder conditions. If m2tsPacketsPerObject is present, it declares the usual number of source packets per media Object. The final Object of a Group MAY contain fewer source packets. Receivers MUST use the actual Object payload length rather than assuming every Object has the declared size. 5.5. Source Handling and Carriage Modes A publisher carries a transport stream in one of three modes, signaled by the required m2tsModified field (Section 6.3) and the optional m2tsEsPid field (Section 6.14). When m2tsModified is false, the publisher forwards the source packets without modification (unmodified carriage). When m2tsModified is true and m2tsEsPid is absent, the publisher has modified the stream at the program level (modified carriage). When m2tsModified is true and m2tsEsPid is present, the track carries a single elementary stream (ES-level carriage). The m2tsMpts field (Section 6.15) indicates whether the track carries a single program or a whole multiplex, and it alone controls the presence of the per-program fields. 5.5.1. Unmodified Carriage When m2tsModified is false, the publisher forwards the source packets without modification: no program selection, no packet identifier remap, no PAT or PMT rewrite, and no insertion or removal of null packets. A receiver can reconstruct the source stream byte-for-byte. When the source is a single-program transport stream, m2tsMpts is false. The source Program Association Table already lists exactly one program, so the per-program fields m2tsProgramNumber, m2tsPmtPid, and m2tsPcrPid SHOULD be present to identify the carried program. When the source is a multi-program transport stream, m2tsMpts is true and all source packets are emitted as received. Because no program is selected, the per-program fields m2tsProgramNumber, m2tsPmtPid, and m2tsPcrPid MUST be absent, and per-track program subscription and the subscriber join behavior defined in this document do not apply. Group boundary placement depends on whether the publisher can identify random access points across the multiplex: if it can, it MAY align Group boundaries to those points and set m2tsRandomAccess to true; otherwise it SHOULD start a new Group after a fixed number of Objects. 5.5.2. Modified Carriage When m2tsModified is true, the publisher has changed the source stream, for example by selecting a program, filtering packets, rewriting the PAT or PMT, or adding or removing null packets. A publisher that makes any of these changes MUST set m2tsModified to true. A publisher deriving a per-program track SHOULD filter the source packets so that each track contains only: * Null packets with Packet Identifier (PID) 0x1FFF, which MAY be removed or retained at the publisher's discretion. * Program Association Table packets (PID 0x0000), rewritten to list only the program present in this track. * Program Map Table packets for the selected program (whose PID is listed in the Program Association Table entry for that program). * All packets whose PID is listed in the Program Map Table of the selected program, including the PCR_PID and the PIDs of all elementary streams. Removing null packets changes the inter-packet byte spacing that constant-bit-rate receivers use to recover the mux clock. A subscriber wishing to reconstruct a constant-bit-rate output stream cannot derive the original rate from the stream alone; publishers that remove null packets SHOULD declare the source mux rate using m2tsMuxRate (Section 6.9). These rules apply to unscrambled transport stream sources. Publishers filtering scrambled transport streams MUST also retain the conditional access packets required for descrambling; conditional access integration is application-specific and outside the scope of this document. The Program Map Table references only the PIDs of the selected program's elementary streams and PCR; it does not reference the service information (SI) tables defined by Digital Video Broadcasting (DVB) and the Advanced Television Systems Committee (ATSC): Network Information Table (NIT, 0x0010), Service Description Table and Bouquet Association Table (SDT/BAT, 0x0011), Event Information Table (EIT, 0x0012), and Time and Date Table with Time Offset Table (TDT/TOT, 0x0014), or their ATSC Program and System Information Protocol (PSIP) equivalents. The filter therefore drops these tables, leaving the resulting track without service identity, Electronic Program Guide (EPG), or broadcast time. Publishers producing tracks for broadcast or Integrated Receiver Decoder (IRD) reception SHOULD retain the SI tables required by the target standard. When SI tables are retained, publishers SHOULD declare the additional PIDs using m2tsSiPids (Section 6.10) so that subscribers can verify which tables are present. Because SDT and EIT carried from an MPTS describe all programs in the multiplex, publishers SHOULD filter or rewrite these tables to include only the service and schedule entries for the carried program; NIT and TDT/TOT are broadcast-wide and do not require per-program rewriting. The m2tsProgramNumber field (Section 6.5) SHOULD be present on per- program tracks to identify the program carried. When multiple per- program tracks are derived from the same MPTS source, the publisher SHOULD use the MSF altGroup field if the programs are alternate renditions of the same content; programs that are independent services SHOULD be published as separate tracks. 5.5.3. Modified ES-Level Carriage When m2tsEsPid (Section 6.14) is present, the track carries a single elementary stream or signaling table. The track payload contains only TS packets for the PID identified by m2tsEsPid; PAT, PMT, and null packets are not included. Publishers SHOULD use the MSF initDataList field to carry the PAT and PMT of the originating program so that subscribers can identify the program structure before processing elementary-stream packets. m2tsPsiInterval MUST be absent, because the track payload contains no PSI. When m2tsPcrPid equals m2tsEsPid, the track embeds the Program Clock Reference and provides the timing reference for the program. When m2tsPcrPid identifies a different PID, that PID is carried by another track; a subscriber requiring PCR-based timing MUST subscribe to the track carrying that PID. A publisher producing multiple ES-level tracks for the same program MUST align Group boundaries across all those tracks so that matching Group numbers correspond to the same presentation position. This alignment allows a subscriber to combine ES-level tracks reliably. A subscriber combining multiple ES-level tracks into a single TS output MUST construct a PAT listing the carried program and a PMT listing the PIDs of all subscribed ES-level tracks, and MUST interleave packets from all tracks. The subscriber sources PCR from the track where m2tsPcrPid equals m2tsEsPid. 5.6. PCR and Timing The Program Clock Reference (PCR) is carried inside adaptation fields of transport-stream packets as defined by [ISO138181]. MOQT Object and Group boundaries are packaging boundaries and do not alter PCR continuity within a track. A publisher MUST NOT introduce a PCR discontinuity within a single MOQT Group. A publisher that introduces a PCR discontinuity between consecutive MOQT Groups MUST signal it by setting the discontinuity_indicator bit (ISO 13818-1 Section 2.4.3.5) in the adaptation field of the first TS packet carrying PCR in the new Group. Note: Hardware IRDs recover the mux clock from the rate at which PCR- bearing packets arrive, not only from their encoded values. MOQT does not guarantee that Object delivery preserves the inter-packet timing of the source stream. Deployments targeting such receivers should account for this constraint and may require a rate-controlled egress that re-paces packets according to the source mux rate. Note: The 33-bit PCR base field wraps around after approximately 26.5 hours of continuous stream time. For long-running live streams this is a normal event; receivers should handle it as a continuous timeline continuation rather than a discontinuity. Receivers that use the MSF Media Timeline [MSF] for playout timing can rely on its monotonic wall-clock abstraction independently of PCR wrap-around. 5.7. Splice Signaling SCTE-35 splice information is carried transparently in the TS stream as splice_info_section() messages on their designated PID. Publishers MAY surface splice events via the MSF Event Timeline [MSF]. This document does not specify SCTE-35 processing. 6. Catalog An m2ts track is described by the MSF catalog [MSF]. This document extends that catalog by defining the m2ts value for the inherited packaging field and additional fields for track objects that use that value. The catalog track name, root catalog fields, common track fields, delta update rules, variable substitution rules, and authorization signaling are inherited unchanged from MSF unless this document explicitly states otherwise. A parser MUST ignore fields it does not understand. 6.1. Track Object Fields Table 1 lists the m2ts-specific fields defined within a track object. +=========================+======================+==============+ | Field | Name | Definition | +=========================+======================+==============+ | M2TS packet size | m2tsPacketSize | Section 6.2 | +-------------------------+----------------------+--------------+ | M2TS modified | m2tsModified | Section 6.3 | +-------------------------+----------------------+--------------+ | M2TS packets per Object | m2tsPacketsPerObject | Section 6.4 | +-------------------------+----------------------+--------------+ | M2TS program number | m2tsProgramNumber | Section 6.5 | +-------------------------+----------------------+--------------+ | M2TS PMT PID | m2tsPmtPid | Section 6.6 | +-------------------------+----------------------+--------------+ | M2TS PCR PID | m2tsPcrPid | Section 6.7 | +-------------------------+----------------------+--------------+ | M2TS PSI interval | m2tsPsiInterval | Section 6.8 | +-------------------------+----------------------+--------------+ | M2TS SI PIDs | m2tsSiPids | Section 6.10 | +-------------------------+----------------------+--------------+ | M2TS mux rate | m2tsMuxRate | Section 6.9 | +-------------------------+----------------------+--------------+ | M2TS random access | m2tsRandomAccess | Section 6.11 | +-------------------------+----------------------+--------------+ | M2TS timestamp mode | m2tsTimestampMode | Section 6.12 | +-------------------------+----------------------+--------------+ | M2TS SCTE-35 PID | m2tsScte35Pid | Section 6.13 | +-------------------------+----------------------+--------------+ | M2TS ES PID | m2tsEsPid | Section 6.14 | +-------------------------+----------------------+--------------+ | M2TS MPTS | m2tsMpts | Section 6.15 | +-------------------------+----------------------+--------------+ Table 1 Use of the MSF initRef and initDataList fields by m2ts tracks is described in Section 6.16. 6.2. M2TS Packet Size Required: Yes JSON Type: Number Location: Track Object The source-packet size in octets. The value MUST be either 188 or 192. A value of 188 identifies ordinary MPEG-2 TS packets. A value of 192 identifies M2TS source packets with a four-octet timestamp prefix followed by a 188-octet TS packet. 6.3. M2TS Modified Required: Yes JSON Type: Boolean Location: Track Object When true, the published packet stream is not a byte-for-byte copy of the source. The publisher has changed it, for example by selecting a program, filtering packets, rewriting the PAT or PMT, or adding or removing null packets. When false, the publisher MUST forward the source packets without modification, so a receiver can reconstruct the source stream byte-for-byte. 6.4. M2TS Packets per Object Required: Optional JSON Type: Number Location: Track Object The usual number of source packets carried by each media Object. This field is advisory. Receivers MUST validate each Object using its actual payload length. 6.5. M2TS Program Number Required: Optional JSON Type: Number Location: Track Object The MPEG-2 Transport Stream program number carried by this track. When present, the track SHOULD carry packets from only that program. When absent and m2tsMpts is not true, subscribers MAY select a program using local policy or transport-stream signaling. This field MUST be absent when m2tsMpts is true. 6.6. M2TS PMT PID Required: Optional JSON Type: Number Location: Track Object The packet identifier carrying the Program Map Table for m2tsProgramNumber. This field is advisory and does not replace the Program Association Table or Program Map Table carried in the transport stream. It MUST be absent when m2tsMpts is true. It MUST be absent when m2tsEsPid is present, because an ES-level track does not carry a PMT in its payload. 6.7. M2TS PCR PID Required: Optional JSON Type: Number Location: Track Object The packet identifier carrying the Program Clock Reference for the program identified by m2tsProgramNumber. This field is advisory and does not replace PCR signaling in the transport stream. It MUST be absent when m2tsMpts is true. When m2tsEsPid is present, this PID MAY be carried by a different track in the same session; a subscriber requiring PCR-based timing MUST subscribe to the track where m2tsPcrPid equals m2tsEsPid. 6.8. M2TS PSI Interval Required: Optional JSON Type: Number Location: Track Object The maximum interval, in milliseconds, at which the publisher expects the Program Association Table and Program Map Table to repeat in the packet stream. For single-program tracks, publishers SHOULD repeat PSI at an interval no larger than this value for live content. For m2tsMpts tracks, the publisher does not control PSI injection; when present, this field describes the source multiplex PSI repetition rate and is advisory only. Subscribers MAY use this value to estimate join latency in both modes. This field MUST be absent when m2tsEsPid is present, because ES-level tracks carry no PSI in their payload. 6.9. M2TS Mux Rate Required: Optional JSON Type: Number Location: Track Object The nominal source mux rate of the transport stream in bits per second. This field is advisory. A subscriber reconstructing a constant-bit-rate output stream MAY use this value to restore the original mux rate when null packets have been removed. This field MUST be absent when m2tsEsPid is present. 6.10. M2TS SI PIDs Required: Optional JSON Type: Array Location: Track Object The packet identifiers of SI tables retained in the filtered track, in addition to those listed in the Program Map Table. This field is advisory. Publishers SHOULD include this field when they retain DVB or ATSC SI tables. Subscribers MAY use this list to verify which service information tables are present without inspecting the packet stream. This field MUST be absent when m2tsEsPid is present; at ES- level granularity, each SI table is published as a separate track identified by m2tsEsPid and the MSF role field. 6.11. M2TS Random Access Required: Optional JSON Type: Boolean Location: Track Object When true, the first media Object in every MOQT Group provides a valid random access starting point for the Group. When absent or false, subscribers MUST inspect the transport-stream payload to determine where decoding can begin. 6.12. M2TS Timestamp Mode Required: Optional JSON Type: String Location: Track Object For 192-octet source packets, this field identifies the interpretation of the four-octet source-packet timestamp. The value "arrival-time" indicates an arrival-time or emission-time stamp associated with the following TS packet. The value "opaque" indicates that the timestamp prefix is carried without specified semantics. This field MUST NOT be present when m2tsPacketSize is 188. 6.13. M2TS SCTE-35 PID Required: Optional JSON Type: Number Location: Track Object The PID carrying SCTE-35 splice_info_section() messages for this track. This field is advisory; SCTE-35 messages are also discoverable via the PMT conditional access or registration descriptor. When present, receivers MAY use this value to locate splice events without parsing the PMT. Publishers SHOULD include this field when the track carries SCTE-35 splice signaling. This field MUST be absent when m2tsEsPid is present; when SCTE-35 is published as an ES-level track, the track's m2tsEsPid and role fields identify it. 6.14. M2TS ES PID Required: Optional JSON Type: Number Location: Track Object The Packet Identifier of the single elementary stream or signaling table carried by this track. When present, the track carries only TS packets for this PID; it does not carry PAT, PMT, or null packets. This field MUST be absent when m2tsMpts is true. When m2tsEsPid is present, m2tsModified MUST be true, m2tsPmtPid MUST be absent, m2tsSiPids MUST be absent, and m2tsScte35Pid MUST be absent. For tracks carrying DVB or ATSC service information tables, publishers SHOULD set the MSF role field to one of the following values: "nit" for the Network Information Table (PID 0x0010), "sdt" for the Service Description Table and Bouquet Association Table (PID 0x0011), "eit" for the Event Information Table (PID 0x0012), and "tdt" for the Time and Date Table and Time Offset Table (PID 0x0014). For tracks carrying SCTE-35 splice information, publishers SHOULD set role to "scte35". For media elementary streams, publishers SHOULD set role to the MSF-defined value for the stream type, for example "video" or "audio". 6.15. M2TS MPTS Required: Optional JSON Type: Boolean Location: Track Object When true, this track carries a multi-program transport stream without program selection or PID filtering. m2tsProgramNumber, m2tsPmtPid, and m2tsPcrPid MUST be absent when this field is true. 6.16. Use of MSF Initialization Data The initRef track field and the root initDataList field are defined by MSF; they are not fields defined by this extension. An m2ts track MAY use those fields to carry initialization data. The track sets initRef to the id of an initDataList entry whose type MUST be "inline". The Base64 [BASE64] decoded value of the entry's data field MUST be a sequence of whole source packets using the packet size declared by m2tsPacketSize. Publishers SHOULD include current PAT and PMT packets in the referenced initialization data when those tables are not guaranteed to be available at the first Object of each Group. When PSI changes within a live track, the publisher SHOULD publish an updated initialization data entry in a new independent catalog before publishing media Objects that rely on the changed PSI. An update to the root initDataList MUST NOT be expressed as an MSF delta update. Receivers MUST NOT assume that referenced initialization data remains valid after the MPEG-2 PSI version_number changes; updated PSI in media Objects takes precedence. For m2tsMpts tracks, producing referenced initialization data requires extracting the PAT and all program PMTs from the source multiplex. Publishers that do not inspect the source stream typically omit initRef and the corresponding initDataList entry; subscribers will encounter PSI within one PSI repetition cycle regardless of Group boundaries. 7. Catalog Examples The following examples are non-normative. 7.1. Live 188-octet Transport Stream { "version": "draft-01", "generatedAt": 1746104606044, "tracks": [ { "name": "program-1-ts", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": false, "isLive": true, "targetLatency": 1000, "role": "video", "mimeType": "video/mp2t", "bitrate": 6000000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsProgramNumber": 1, "m2tsPmtPid": 256, "m2tsPcrPid": 257, "m2tsPsiInterval": 100, "m2tsRandomAccess": true } ] } 7.2. Live 192-octet M2TS Source Packets { "version": "draft-01", "generatedAt": 1746104606044, "tracks": [ { "name": "program-1-m2ts", "namespace": "contribution.example.net/feed/a", "packaging": "m2ts", "m2tsModified": false, "isLive": true, "targetLatency": 500, "role": "video", "mimeType": "video/mp2t", "bitrate": 12000000, "m2tsPacketSize": 192, "m2tsPacketsPerObject": 32, "m2tsProgramNumber": 1, "m2tsTimestampMode": "arrival-time", "m2tsRandomAccess": true } ] } 7.3. VOD Transport Stream { "version": "draft-01", "tracks": [ { "name": "asset-main", "namespace": "vod.example.com/assets/1000", "packaging": "m2ts", "m2tsModified": false, "isLive": false, "trackDuration": 632000, "role": "video", "mimeType": "video/mp2t", "bitrate": 4500000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 96, "m2tsProgramNumber": 1, "m2tsRandomAccess": true } ] } 7.4. Multi-Program Source - Per-Program Tracks This example shows a catalog for a publisher that receives a 2-program transport stream and publishes each program as a separate m2ts track. The two tracks share a namespace but are independent services; altGroup is not used because the programs carry different content. { "version": "draft-01", "generatedAt": 1746104606044, "tracks": [ { "name": "program-1", "namespace": "live.example.com/mux/1", "packaging": "m2ts", "m2tsModified": true, "isLive": true, "targetLatency": 1000, "role": "video", "mimeType": "video/mp2t", "bitrate": 6000000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsProgramNumber": 1, "m2tsPmtPid": 256, "m2tsPcrPid": 257, "m2tsPsiInterval": 100, "m2tsRandomAccess": true }, { "name": "program-2", "namespace": "live.example.com/mux/1", "packaging": "m2ts", "m2tsModified": true, "isLive": true, "targetLatency": 1000, "role": "video", "mimeType": "video/mp2t", "bitrate": 4000000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsProgramNumber": 2, "m2tsPmtPid": 512, "m2tsPcrPid": 513, "m2tsPsiInterval": 100, "m2tsRandomAccess": true } ] } 7.5. Transparent MPTS Carriage This example shows a catalog for a publisher that carries a complete multi-program transport stream without program selection, so no per- program catalog fields are present. The m2tsPsiInterval field is included as an advisory hint; its value is not normative for MPTS tracks. { "version": "draft-01", "generatedAt": 1746104606044, "tracks": [ { "name": "mux-1", "namespace": "live.example.com/mux/1", "packaging": "m2ts", "m2tsModified": false, "isLive": true, "targetLatency": 1000, "mimeType": "video/mp2t", "bitrate": 20000000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsMpts": true, "m2tsPsiInterval": 100 } ] } 7.6. ABR Alternate Renditions - Two Bitrate Tracks This example shows a catalog for a live channel published at two bitrates as alternate renditions. Both tracks are in the same altGroup; video tracks MUST align Group boundaries at identical presentation positions. The tracks use different PID assignments: a subscriber switching between them MUST re-parse PAT and PMT on the new track before routing packets to a decoder. { "version": "draft-01", "generatedAt": 1746104606044, "tracks": [ { "name": "video-high", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": false, "isLive": true, "targetLatency": 1000, "role": "video", "mimeType": "video/mp2t", "bitrate": 6000000, "altGroup": 1, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsProgramNumber": 1, "m2tsPmtPid": 256, "m2tsPcrPid": 257, "m2tsPsiInterval": 100, "m2tsRandomAccess": true }, { "name": "video-low", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": false, "isLive": true, "targetLatency": 1000, "role": "video", "mimeType": "video/mp2t", "bitrate": 2000000, "altGroup": 1, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsProgramNumber": 1, "m2tsPmtPid": 512, "m2tsPcrPid": 513, "m2tsPsiInterval": 100, "m2tsRandomAccess": true } ] } 7.7. ES-Level Tracks - Per-Elementary-Stream Publishing This example shows a live program published as separate ES-level tracks: one video track carrying the PCR, two audio tracks for different languages (English and Spanish), and one Event Information Table track. The video and audio tracks MUST have synchronized Group boundaries. A subscriber combines the video track and the audio track of its choice by constructing a PAT and PMT listing the subscribed PIDs and sourcing PCR from the video track (PID 257). { "version": "draft-01", "generatedAt": 1746104606044, "tracks": [ { "name": "program-1-video", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": true, "isLive": true, "targetLatency": 1000, "role": "video", "mimeType": "video/mp2t", "bitrate": 5000000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 64, "m2tsProgramNumber": 1, "m2tsPcrPid": 257, "m2tsEsPid": 257, "m2tsRandomAccess": true }, { "name": "program-1-audio-en", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": true, "isLive": true, "targetLatency": 1000, "role": "audio", "mimeType": "video/mp2t", "bitrate": 128000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 32, "m2tsProgramNumber": 1, "m2tsPcrPid": 257, "m2tsEsPid": 258, "m2tsRandomAccess": true }, { "name": "program-1-audio-es", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": true, "isLive": true, "targetLatency": 1000, "role": "audio", "mimeType": "video/mp2t", "bitrate": 128000, "m2tsPacketSize": 188, "m2tsPacketsPerObject": 32, "m2tsProgramNumber": 1, "m2tsPcrPid": 257, "m2tsEsPid": 259, "m2tsRandomAccess": true }, { "name": "program-1-eit", "namespace": "live.example.com/channel/1", "packaging": "m2ts", "m2tsModified": true, "isLive": true, "role": "eit", "mimeType": "video/mp2t", "m2tsPacketSize": 188, "m2tsPacketsPerObject": 16, "m2tsProgramNumber": 1, "m2tsEsPid": 18 } ] } 8. Subscriber Processing A subscriber obtains the catalog using the MSF catalog workflow and subscribes to one or more m2ts tracks. For each received media Object, the subscriber: 1. Validates that the payload length is a non-zero integer multiple of m2tsPacketSize. 2. Validates the TS sync byte position for each source packet. 3. Reconstructs the packet stream by appending the source packets in MOQT object order. 4. Applies normal MPEG-2 Transport Stream demultiplexing, timing recovery, and decoder initialization. If validation fails, the subscriber SHOULD discard the invalid Object and treat the reconstructed packet stream as discontinuous. A subscriber MAY continue processing at the next Object, but it SHOULD wait for a random access point before presenting decoded media. When joining a live track, a subscriber SHOULD start at the newest Group whose first Object is available when m2tsRandomAccess is true. Otherwise, a subscriber SHOULD select a starting Group far enough back to encompass at least one complete PSI repetition cycle before its target presentation time; when m2tsPsiInterval is declared, that value bounds the maximum look-back interval needed. A subscriber MAY use the MSF Media Timeline [MSF] to resolve this time bound to a concrete MOQT Group location for use with a Joining FETCH [MOQTransport]. A subscriber MUST NOT begin media presentation until it has received a valid PAT and PMT for the program to be decoded. When a subscriber receives ES-level tracks (Section 5.5.3), it MUST align on the same starting Group number across all subscribed ES- level tracks for the same program before combining them. The subscriber constructs the combined TS output by building a PAT listing the carried program and a PMT listing the PIDs of all subscribed ES-level tracks, then interleaving packets from all tracks. PCR is sourced from the track where m2tsPcrPid equals m2tsEsPid. A subscriber MUST NOT begin media presentation until it has received at least one Group from each subscribed ES-level track and has obtained the originating program's PAT and PMT, either from initDataList or from the packet stream. 9. Switching and Alternate Renditions Tracks with m2tsMpts set to true MUST NOT be included in an altGroup, because ABR switching semantics require per-program Group alignment and PCR continuity that transparent carriage does not guarantee. Multiple m2ts tracks can be advertised as alternatives using the MSF altGroup field. Video tracks in the same alternate group MUST place Group boundaries at identical presentation positions; other tracks SHOULD align their Group boundaries to the same positions where possible. All tracks in the alternate group SHOULD set m2tsRandomAccess to true. This ensures that a subscriber can switch between alternate video tracks at any Group boundary without encountering a misaligned access point. A subscriber SHOULD switch between alternate m2ts tracks only at Group boundaries or at transport-stream random access points that it can independently decode. This document does not require continuity counter values or PID assignments to match across alternate tracks. Receivers MUST treat a switch between tracks as a packet-stream discontinuity unless application-specific signaling establishes stronger continuity. A receiver MUST treat a switch between alternate tracks as a PCR discontinuity and MUST re-initialize its system time clock (STC) recovery using the first PCR value received on the new track as the initial reference. In addition to the Group boundary alignment requirements above, publishers providing alternate tracks SHOULD align presentation timestamps at Group boundaries across tracks to enable seamless presentation switching at the application layer. Because PID assignments need not match across alternate tracks, a receiver MUST re-parse the PAT and PMT of the new track after every track switch before routing elementary-stream packets to a decoder. 10. Content Protection This packaging format preserves any scrambling or conditional access information present in the MPEG-2 Transport Stream. Transport-stream scrambling is opaque to MOQT relays and to this specification. Object-level encryption MAY be applied using a mechanism such as MOQ Secure Objects [SecureObjects] when signaled by the catalog. When object-level encryption is used, source packet validation is performed after successful decryption. 11. Authorization Authorization requirements can be advertised using MSF catalog authorization fields. For example, a publisher can use Common Access Token signaling [C4M], Privacy Pass authorization [PrivacyPassAuth], or an application defined authorization scheme. 12. Security Considerations The security considerations of MOQT [MOQTransport], MSF [MSF], MPEG-2 Transport Stream [ISO138181], and any object encryption scheme apply. Receivers need to treat transport-stream syntax as untrusted input. Invalid packet sizes, invalid sync bytes, malformed PSI, inconsistent continuity counters, excessive table repetition, and timestamp discontinuities can cause decoder failures or resource exhaustion if not bounded by implementation policy. Catalog metadata is also untrusted input. Subscribers MUST validate packet sizes, payload lengths, Base64 values, PIDs, program numbers, and object ordering before using the values to allocate memory or configure decoders. Object-level encryption protects MOQT Object payloads but does not hide MOQT namespace, track name, Group ID, Object ID, object size, or delivery timing from authorized relays. Applications that require confidentiality for media payloads SHOULD use an object encryption scheme in addition to transport security. 13. IANA Considerations This document requests that, once MSF establishes an IANA registry for packaging values, IANA register the value "m2ts" with this document as the reference. 14. References 14.1. Normative References [BASE64] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, . [ISO138181] ISO/IEC, "Information technology - Generic coding of moving pictures and associated audio information: Systems", ISO/IEC 13818-1, 2023. [MOQTransport] Nandakumar, S., Vasiliev, V., Swett, I., and A. Frindell, "Media over QUIC Transport", Work in Progress, Internet- Draft, draft-ietf-moq-transport-19, 6 July 2026, . [MSF] Law, W. and S. Nandakumar, "MOQT Streaming Format", Work in Progress, Internet-Draft, draft-ietf-moq-msf-01, 2 June 2026, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . 14.2. Informative References [C4M] Law, W., Lemmons, C., Simon, G., and S. Nandakumar, "Authorization scheme for MOQT using Common Access Tokens", Work in Progress, Internet-Draft, draft-ietf-moq- c4m-01, 18 June 2026, . [PrivacyPassAuth] Nandakumar, S., Jennings, C. F., and T. Meunier, "Privacy Pass Authentication for Media over QUIC (MoQ)", Work in Progress, Internet-Draft, draft-ietf-moq-privacy-pass- auth-03, 6 July 2026, . [SecureObjects] Jennings, C. F., Nandakumar, S., and R. Barnes, "End-to- End Secure Objects for Media over QUIC Transport", Work in Progress, Internet-Draft, draft-ietf-moq-secure-objects- 01, 6 July 2026, . Appendix A. Acknowledgments This document follows the repository and draft structure used by the MOQT Streaming Format work. Authors' Addresses Paul Gregoire Red5 Email: paul@red5.net Gwendal Simon Synamedia Email: gsimon@synamedia.com