ANSI SCTE 242-2-2017 pdf free download.Next Generation Audio Coding Constraints for Cable Systems: Part 2 – AC-4 Audio Coding Constraints
1.1. Scope
This document is part two of a three-part standard that specifies the coding constraints of Next Generation Audio system for cable television. In conjunction with SCTE 242-1 2017 [1], this document defines the coding constraints on AC-4 for cable television.
The carriage of the streams described in this specification is defined in SCTE 243-2 2017 [9] in conjunction with SCTE 243-1 2017 [8].
2. Normative References
The following documents contain provisions, which, through reference in this text, constitute provisions of this document. At the time of Subcommittee approval, the editions indicated were valid. All documents are subject to revision; and while parties to any agreement based on this document are encouraged to investigate the possibility of applying the most recent editions of the documents listed below, they are reminded that newer editions of those documents might not be compatible with the referenced version.
2.1. SCTE References
[1] SCTE 242-1 2017, Next Generation Audio Coding Constraints for Cable Systems: Part 1 –
Introduction and Common Constraints
2.2. Standards from Other Organizations
[2] ATSC S34-187r12, ATSC Candidate Standard: A/342 Part 1, Audio Common Elements
[3] ATSC S34-188r7, ATSC Candidate Standard: A/342 Part 2, AC-4 System
[4] ATSC A/85:2013, ATSC Recommended Practice: Techniques for Establishing and
Maintaining Audio Loudness for Digital Television
[5] ETSI TS 103 190-1 V1.2.1 (2015-06), Digital Audio Compression (AC-4) Standard; Part 1:
Channel based coding
[6] ETSI TS 103 190-2 V1.1.1 (2015-08-30), Digital Audio Compression (AC-4) Standard; Part
2: Immersive and personalized audio
3. Informative References
The following documents might provide valuable information to the reader but are not required when
complying with this document.
3.1. SCTE References
[7] ANSI/SCTE 54 2015, Digital Video Service Multiplex and Transport Subsystem Standard
for Cable Television
[8] SCTE 243-1 2017, Next Generation Audio Carriage Constraints for Cable Systems: Part 1
– Common Transport Signaling
[9] SCTE 243-2 2017, Next Generation Audio Carriage Constraints: Part 2 – AC-4 Audio
Carriage Constraints
6. AC-4 System Overview
AC-4 is a highly efficient audio codec that supports legacy channel-based content, object-based and
channel-based immersive content, personalized content, and advanced metadata as defined in ETSI TS 103 190-2 [6].
A complete description of the AC-4 system features is available in ATSC A/342 Part 1 [2] section 5.1 and A/342 Part 2 [3] section 4.
7. AC-4 Coding Specifications
AC-4 audio elementary streams shall comply with the syntax and semantics contained in ETSI TS 103
190-2 [6] , as well as the parts of ETSI TS 103 190-1 [5] referenced by ETSI TS 103 190-2 [6] , as
constrained in the following sections.
7.1. General Coding Constraints
AC-4 audio elementary streams shall comply with the constraints defined in ATSC A/342 Part 2 [3],
Section 5.2.
7.2. Loudness and DRC Constraints
In order to comply with the loudness recommendations in ATSC A/85 [4], AC-4 audio elementary
streams shall comply with the constraints defined in ATSC A/342 Part 2 [3], Section 5.3.
7.3. Personalized Audio Constraints
In order to provide a consistent listener experience, AC-4 audio elementary streams shall comply with the constraints defines in ATSC A/342 Part 2 [3], Section 5.4.
7.4. Multi-Stream (Hybrid) Constraints
When AC-4 presentations reference audio elements that are contained in more than one elementary
stream, the relevant AC-4 audio elementary streams shall comply with the constraints defined in ATSC A/342 Part 2 [3], Section 5.5.
