SCTE 193-2 2025

MPEG-4 AAC Family Audio System – Part 2 Constraints for Carriage over MPEG-2 Transport

Executive Summary

This document is part of a suite documenting coding constraints of MPEG 4 AAC, HE AAC and HE AAC v2 systems for cable television (see SCTE 193-1 [1]).

Scope

This document describes the carriage of MPEG-4 AAC, HE AAC, HE AAC v2, and Extended HE-AAC (referred to collectively in this document as the “AAC family”) profile audio in MPEG-2 transport systems. It also discusses MPEG-2 AAC LC profile audio, which is closely related to MPEG-4 AAC profile audio.

The descriptor necessary to signal AAC family audio and information for signaling mixing of main and associated services in the receiver are defined in this document. Multiplexing and transport for cable using MPEG-2 systems are defined in SCTE 54 [10]. Coding constraints for AAC family audio elementary streams are defined in SCTE 193-1 [1]..

Benefits

The MPEG 4 AAC audio system provides excellent audio fidelity at low bit rates. It supports mono, stereo and multi-channel audio operational modes. HE AAC and HE AAC v2 incorporate audio metadata including metadata to control audio loudness.

Intended Audience

Content providers, distributors and equipment manufacturers that use MPEG 4 AAC audio coding.