A/331, “Signaling, Delivery, Synchronization, and Error Protection”Approved: 19 January 2021

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.

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.