ANSI SCTE 242-1-2017 pdf free download – Next Generation Audio Coding Constraints for Cable Systems: Part 1 – Introduction and Common Constraints.
1. Scope
This document is part of a suite documenting coding constraints of Next Generation Audio (NGA) systems for cable television. It is intended to be used in conjunction with the specific audio technologies described in subsequent Parts of this standard.
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. Standards from Other Organizations
[1] ATSC CS A/342 Audio, Part 1: Audio Common Elements
3. Informative References
[2] SCTE 243-1 2017, Next Generation Audio Carriage Constraints for Cable Systems: Part 1 – Common Transport Signaling
5.2. Definitions
This document uses the terminology specific to the ATSC 3.0 audio system as defined in ATSC A/342-1Clause 4 [1 ].Additionally , the following definitions are used:
Audio Preselection: set of Audio Program Components representing a version of the Audio Program thatmay be selected by a user for simultaneous decoding.An Audio Preselection is a sub-selection from allavailable Audio Program Components of one Audio Program. An Audio Preselection can be consideredthe NGA equivalent of audio services in predecessor systems, whereby each audio service comprises acomplete audio mix.
6.System overview
6.1. Features of NGA Systems
A description of the main features of Next Generation Audio systems is provided in ATSC A/342-1subclause 5.1 [1].
6.2.NGA Concepts
Several concepts are common to all NGA systems (e.g., systems supported by ATSC 3.0).This sectiondescribes these common concepts.
6.2.1. Audio Program Components and Preselections
Audio Program Components are separate pieces of audio data that are combined to compose an AudioPreselection. A simple Audio Preselection may consist of a single Audio Program Component, such as aComplete Main Mix for a television program.Audio Preselections that are more complex may consist ofseveral Audio Program Components,such as ambient music and effects, combined with dialog and videodescription.
Audio Preselections are combinations of Audio Program Components representing versions of the audioprogram that may be selected by a user. For example, a complete audio with English dialog, a completeaudio with Spanish dialog, a complete audio(English or Spanish) with video description, or a completeaudio with alternate dialog may all be selectable Preselections for a Program.
The Components of a Preselection can be delivered in a single audio Elementary Stream or in multipleaudio Elementary Streams.
6.2.2.Audio Element Formats
The NGA systems support three fundamental Audio Element Formats:
1) Channel Sets are sets of Audio Elements consisting of one or more Audio Signals presenting sound to speaker(s) located at canonical positions. These include configurations such as mono, stereo, or 5.1, and extend to include non-planar configurations, such as 7.1+4. 2) Audio Objects are Audio Elements consisting of audio information and associated metadata representing a sound’s location in space (as described by the metadata). The metadata may be dynamic, representing the movement of the sound. 3) Scene-based audio (e.g., HOA) consists of one or more Audio Elements that make up a generalized representation of a sound field.ANSI SCTE 242-1 pdf download.