A/331, “Signaling, Delivery, Synchronization, and Error Protection”Approved: 16 August 2023

This document specifies protocols used for delivery and synchronization of media and non-timed data in the ATSC 3.0 system. A/331 specifies the technical mechanisms and procedures pertaining to service signaling and IP-based delivery of a variety of ATSC 3.0 services and contents to ATSC 3.0-capable receivers over broadcast, broadband, and hybrid broadcast/broadband networks. The service signaling functionality defines the data formats and information components necessary to discover and acquire user services. The IP-based delivery functionality specifies two application transport protocols for the carriage of media content and service signaling data over broadcast and/or broadband networks to receivers. The delivery functionality also includes mechanisms for the synchronization of media components delivered on the same or different transport networks, and application-layer forward error correction methods that enable error-free reception and consumption of media streams or discrete file objects. A component of this standard is the accompanying schema.

Download current version: A/331:2023-08, “Signaling, Delivery, Synchronization, and Error Protection”, 16 August 2023, and accompanying schema.

Previous Versions

There are multiple versions of this document. Please be sure to download the desired version. For amendments, the text includes a list of changes, the rationale for the changes, and compatibility considerations.

Download A/331:2019, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, approved 20 June 2019. This version is referenced by A/300:2019.

Download A/331:2019 Amendment No. 1, “MMT Hybrid Delivery”, approved 6 January 2020.

Download A/331:2019 Amendment No. 2, “Fix Daylight Saving”, approved 16 January 2020.

Download A/331:2019 Amendment No. 3, “ServiceId URL and BSID-PLP Mapping”, approved 26 December 2019.

Download A/331:2019 Amendment No. 4, “User Agent String”, approved 15 January 2020.

Download A/331:2019 Amendment No. 5, “Fix RRT”, approved 30 December 2019.

Download A/331:2019 Amendment No. 6, “Simulcast TSID”, approved 31 December 2019.

Download A/331:2019 Amendment No. 7, “DRM System ID”, approved 3 January 2020.

Download A/331:2019 Amendment No. 8, “Uniqueness of @serviceID”, approved 1 January 2020.

Download A/331:2019 Amendment No. 9, “Fix Keep Screen Clear”, approved 2 January 2020.

Download A/331:2020, “Signaling, Delivery, Synchronization, and Error Protection”, 16 January 2020. This document is a rollup of Amendments No. 1 through 9 to A/331:2019. The accompanying schema (unchanged from A/331:2019) can be downloaded from the above link. This version is referenced by A/300:2020.

Download A/331:2020 Amendment No. 1, “Multiple App Fixes”, approved 27 October 2020. See also the accompanying schema.

Download A/331:2020 Amendment No. 2, “AEAT Subgroups”, approved 19 January 2021. See also the accompanying schema.

Download A/331:2021, “Signaling, Delivery, Synchronization, and Error Protection”, 19 January 2021, and accompanying schema. This document is a rollup of A/331:2020 with Amendments No. 1 and 2.

Download A/331:2021 Amendment No. 1, “RRT Schema”, and accompanying schema, approved 22 April 2021.

Download A/331:2021 Amendment No. 2, “Advanced Emergency Information”, and accompanying schema, approved 27 May 2021.

Download A/331:2021 Amendment No. 3, “HELD Processing Order”, approved 8 June 2021.

Download A/331:2021 Amendment No. 4, “User Agent”, approved 1 October 2021.

Download A/331:2021, “Signaling, Delivery, Synchronization, and Error Protection, with Amendments No. 1, 2, and 3”. This document has Amendments No. 1, 2, and 3 integrated into the standard. An administrative rollup of the schemas for A/331:2021 with Amendments No. 1, 2, and 3 is also available: download the ZIP file. This version is referenced by A/300:2021.

Download A/331:2021, “Signaling, Delivery, Synchronization, and Error Protection, with Amendments No. 1, 2, 3, and 4”. This document has Amendments No. 1, 2, 3, and 4 integrated into the standard. An administrative rollup of the schemas for A/331:2021 with Amendments is also available: download the ZIP file.

Download A/331:2021 Amendment No. 5, “Broadcast-Broadband Configuration Signaling”, approved 9 November 2021.

Download A/331:2022-02, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, approved 15 February 2022.

Download A/331:2022-03, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, 31 March 2022. This version of the Standard is normatively referenced in A/300:2022-04.

Download A/331:2022-03 Corrigendum No. 1, “SLT and S-TSID”, approved 22 September 2022.

Download A/331:2022-09, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, 22 September 2022.

Download A/331:2022-09 Amendment No. 1, “Signaling Server”, approved 30 November 2022.

Download A/331:2022-11, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, 30 November 2022.

Download A/331:2022-11 Amendment No. 1, “Application Lifecycle”, approved 8 February 2023.

Download A/331:2022-11 Amendment No. 2, “Timing/Buffer Model – IMSC1”, approved 16 February 2023.

Download A/331:2023-02, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, 23 March 2023.

Download A/331:2023-03, “Signaling, Delivery, Synchronization, and Error Protection”, and accompanying schema, 28 March 2023. This version of the Standard is normatively referenced in A/300:2023-03.

Download A/331:2023-03 Amendment No. 1, “MMT DRM”, approved 16 August 2023.