IEC 61937-16:2024

Digital audio – Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 – Part 16: AVSA

IEC 61937-16:2024 describes the method to convey non-linear PCM bitstreams encoded in accordance with the AVSA format.

General Information

• Status: Published
• Publication Date: 28-Nov-2024
• ICS: 33.160.30 - Audio systems
• ICS: 35.040.40 - Coding of audio, video, multimedia and hypermedia information
• Technical Committee: TA 20 - Analogue and digital audio
• Drafting Committee: PT 61937-16 - TC 100/TA 20/PT 61937-16
• Current Stage: PPUB - Publication issued
• Start Date: 29-Nov-2024
• Completion Date: 20-Dec-2024

Overview

IEC 61937-16:2024 is the latest international standard published by the International Electrotechnical Commission (IEC) that specifies an interface for transmitting non-linear PCM encoded audio bitstreams formatted according to the AVSA (Audio and Video Standardized Audio) encoding scheme. As part of the IEC 61937 series, this standard defines how AVSA audio data streams are conveyed over the IEC 60958 digital audio interface, ensuring interoperability between audio sources and receivers that handle non-linear PCM audio.

The AVSA format aligns with IEEE Std 1857.8-2020 and the equivalent GB/T 33475.3 Chinese standard for advanced audio coding. IEC 61937-16:2024 elaborates on the bitstream mapping, data-burst structures, timing, and synchronization mechanisms essential for efficient and reliable AVSA audio transport.

Key capabilities embraced by this standard include detailed specification of AVSA data bursts, pause data bursts to fill stream gaps, synchronization of audio to video streams through latency parameters, and use of extended data-type identifiers allowing flexible and future-proof encoding.

Key Topics

• Bitstream Mapping: Defines how AVSA audio bitstreams are mapped onto IEC 60958 frames with specific preamble and burst-info fields. It mandates usage of extended data-type indicators to distinguish AVSA content within the data bursts.

• Data-Burst Structure: Describes the format of AVSA data bursts, consisting of a preamble and payload parts, with detailed information on the arrangement of fields such as Pa, Pb, Pc, Pd, and extended fields Pe and Pf.

• Pause Data Burst: Specifies the use of pause bursts to handle stream gaps or pauses in audio transmission. These bursts help maintain continuous stream timing and synchronization despite audio silence intervals.

• Latency and Synchronization: Defines latency as the sum of receiving and decoding delays for AVSA frames. The standard provides formulas and timing diagrams to facilitate synchronization of audio playback with video, ensuring seamless AV and multimedia experiences.

• Repetition Periods: Details how repetition periods for audio and pause data bursts are derived based on frame length and sampling rate parameters within the AVSA bitstream, critical for maintaining sample-accurate timing.

• Compliance with IEC 60958: Establishes full compliance with the IEC 60958 digital audio interface standard, allowing AVSA bitstreams to be conveyed over widely deployed professional and consumer digital audio interfaces.

Applications

IEC 61937-16:2024 finds practical application across industries and technologies including:

• Digital Audio Broadcasting: Facilitates transmission of high-quality non-linear PCM audio using AVSA encoding over digital broadcast systems supporting IEC 60958 interfaces.

• Professional Audio Equipment: Ensures seamless transport of AVSA encoded signals in studio and live environments where synchronization and low latency are critical.

• Consumer Electronics: Supports next-generation AV receivers, soundbars, and home theaters that decode AVSA-encoded content via S/PDIF or HDMI connections utilizing IEC 60958 interface standards.

• Multimedia Systems: Enables robust audio-video synchronization in multimedia frameworks, streaming platforms, and digital signage that require precise timing of encoded non-linear PCM audio.

• High-Efficiency Audio Coding: Works with AVSA’s bandwidth extension features for efficient storage and transmission of audio content without compromising quality.

Related Standards

• IEC 60958 (All Parts): The foundational digital audio interface standard to which IEC 61937-16 extends AVSA signaling methods.

• IEC 61937-1:2021: General part of the IEC 61937 series detailing interface requirements for non-linear PCM encoded bitstreams.

• IEEE Std 1857.8-2020: Defines the AVSA audio coding format and bandwidth extension methodologies.

• GB/T 33475.3: Chinese high-efficiency media coding standard equivalent to IEEE 1857.8, fully compatible with AVSA specification.

• IEC 61937 Series: Other parts detail interfacing methods for different encoded audio formats like Dolby Digital, DTS, MPEG audio, enabling broad interoperability across audio coding standards and transport mechanisms.

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By adopting IEC 61937-16:2024, audio manufacturers, developers, and broadcasters gain a robust, standardized approach for transporting AVSA encoded non-linear PCM audio streams. This enhances compatibility, streamlines product development, and supports the continuous evolution of digital audio technologies globally.

Standards Content (Sample)

IEC 61937-16 ®
Edition 1.0 2024-11
INTERNATIONAL
STANDARD
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 16: AVSA
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IEC 61937-16 ®
Edition 1.0 2024-11
INTERNATIONAL
STANDARD
Digital audio – Interface for non-linear PCM encoded audio bitstreams applying
IEC 60958 –
Part 16: AVSA
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.30; 35.040.40 ISBN 978-2-8327-0025-9
– 2 – IEC 61937-16:2024 © IEC 2024
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Mapping of the audio bitstream on to IEC 61937-1 . 6
4.1 General . 6
4.2 AVSA burst-info . 6
5 Format of AVSA data-burst . 6
5.1 General . 6
5.2 Pause data-burst . 6
5.3 Audio data-burst . 7
5.3.1 The AVSA data . 7
5.3.2 Latency of AVSA decoding . 8
5.3.3 The AVSA BWE data . 9
5.3.4 Latency of AVSA BWE decoding . 10
Figure 1 – AVSA data-burst structure . 7
Figure 2 – Latency of AVSA decoding . 8
Figure 3 – AVSA BWE data-burst structure . 9
Figure 4 – Latency of AVSA BWE decoding . 10
Table 1 – Fields of burst-info . 6
Table 2 – Repetition period of pause data-burst . 7
Table 3 – Data-type-dependent information for AVSA . 8
Table 4 – Data-type-dependent information for AVSA BWE . 9

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED
AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 16: AVSA
FOREWORD
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IEC 61937-16 has been prepared by technical area 20: Analogue and digital audio, of IEC
technical committee 100: Audio, video and multimedia systems and equipment. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
100/4108/CDV 100/4164/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
– 4 – IEC 61937-16:2024 © IEC 2024
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
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A list of all parts in the IEC 61937 series, published under the general title Digital audio –
Interface for non-linear PCM encoded audio bitstreams applying IEC 60958, can be found on
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DIGITAL AUDIO –
INTERFACE FOR NON-LINEAR PCM ENCODED
AUDIO BITSTREAMS APPLYING IEC 60958 –

Part 16: AVSA
1 Scope
This part of IEC 61937 describes the method to convey non-linear PCM bitstreams encoded in
accordance with the AVSA format.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60958 (all parts), Digital audio interface
IEC 61937-1:2021, Digital audio – Interface for non-linear PCM encoded audio bitstreams
applying IEC 60958 – Part 1: Gene
...