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: 20-Dec-2024
• Completion Date: 29-Nov-2024

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
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
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
the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
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: General
IEEE Std 1857.8-2020, IEEE Standard for Second Generation Audio Coding
GB/T 33475.3, Information technology – High efficiency media coding – Part 3: Audio
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61937-1 and the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
AVSA frame
audio stream defined in IEEE Std 1857.8 and GB/T 33475.3, where GB/T 33475.3 is an
equivalent standard (a Chinese version of IEEE Std 1857.8)
3.2
AVSA BWE frame
AVSA bandwidth extension frame defined in IEEE Std 1857.8 and GB/T 33475.3, where GB/T
33475.3 is an equivalent standard (a Chinese version of IEEE Std 1857.8)
3.3
frame length
number of linear PCM audio samples per AVSA frame

– 6 – IEC 61937-16:2024 © IEC 2024
3.4
latency
delay time of an external audio decoder to decode an AVSA audio data-burst defined as the
sum of the values of the receiving delay time and the decoding delay time
4 Mapping of the audio bitstream on to IEC 61937-1
4.1 General
The coding of the bitstream and data-burst is in accordance with IEC 61937-1:2021, including
field names such as "Pc", "Pa" and "R".
4.2 AVSA burst-info
As all bits are used in the preamble word of Pc, the value of data-type bits 0 to 4 in Pc are set
to be 1 Fh and the value of data-type bits 5 to 6 in Pc are set to be 0. The extended data-type
burst preamble Pe is used and the value is set to be 0x0001 h. The 32-bit burst-info contains
information about the data which will be found in the data-burst (see Table 1).
Table 1 – Fields of burst-info
Data-type Data-type Extended data-type Data-type Contents Reference Repetition
point R period of data-
Value of Value of Value of Pe bits 0 Value of
burst measured
Pc bits 0 Pc bits 5 to 15 Pc bits 8
in IEC 60958
to 4 to 6 to 9
frames
0x1F 0 0x0001 0 AVSA bit 0 of Pa see Table 3
1 AVSA BWE bit 0 of Pa see Table 4
2 or 3 reserved for future use
0x0002 to 0xFFFF reserved for future use
1 to 3 Extended data-type (do not use until defined)

Bits 0 to 6 of the burst-info (Pc) and bits 0 to 15 of the burst-info (Pe) signal the data-type used
for transmission. For AVSA, the signaled extended data-type is 0x0001h.
The Pc bits 8 to 9 indicate the AVSA bitstream mode. The repetition periods of data bursts in
IEC 60958 frames shall be determined from the data-type-dependent information specified in
Table 3 and Table 4
...