ISO 26428-3:2008

Digital cinema (D-cinema) distribution master - Part 3: Audio channel mapping and channel labeling

ISO 26428-3:2008 defines the mapping and labeling of channels for the digital cinema distribution master audio in a digital cinema audio system to aid the identification and location of channels. This allows uniform expression and communication of source audio channels to digital cinema playback loudspeakers.

Souche de la distribution du cinéma numérique (cinéma D) — Partie 3: Cartographie de la chaîne sonore et marquage de la chaîne sonore

General Information

• Status: Published
• Publication Date: 19-Aug-2008
• ICS: 35.040 - Information coding
• ICS: 35.040.40 - Coding of audio, video, multimedia and hypermedia information
• ICS: 37.060.99 - Other standards related to cinematography
• Technical Committee: ISO/TC 36 - Cinematography
• Drafting Committee: ISO/TC 36 - Cinematography
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 30-May-2024
• Completion Date: 13-Dec-2025

Overview

ISO 26428-3:2008 (Digital cinema (D‑cinema) distribution master - Part 3) specifies audio channel mapping and channel labeling for the Digital Cinema Distribution Master (DCDM). Adopted from SMPTE 428‑3‑2006, this standard defines how source audio channels are numbered, labeled and communicated to playback loudspeakers in a digital cinema audio system to ensure consistent identification and placement of channels across production, distribution and exhibition workflows.

Key topics and technical requirements

• Channel mapping tables for common channel counts (one, two, four, six, seven, eight, nine): standard channel numbers and labels (e.g., L, C, R, LFE, Ls, Rs, Lc, Rc, Cs).
• AES3 pairing guidance: if AES3 serial digital audio carriage is used, channel pairs and channel‑number mapping are defined so AES3 pairs map to the DCDM channel positions.
• Label retention: channel labels must be retained and communicated consistently throughout the audio chain (from source to playback).
• Supplemental channel labels: predefined labels for additional / future channels such as Vhl/Vhc/Vhr (vertical height), Ts (top center surround), Lw/Rw (left/right wide), Lfe2, Rls/Rrs (rear surround), HI (hearing impaired) and VI‑N (narration).
• Reserved and user‑defined slots: certain channel numbers are SMPTE reserved or marked user‑defined to allow future expansion while preserving compatibility with legacy systems.
• Scope limits: the standard specifies mapping and labeling only - it does not mandate channel content suitability, loudspeaker count, or rendering methods.

Applications and who uses it

• Post‑production and mixing: sound mixers and re‑recording engineers use ISO 26428‑3 labels to produce DCDM audio tracks that map predictably to cinema loudspeakers.
• Content distribution: studios and content distributors use the mapping to package audio metadata and ensure consistent playback in cinemas.
• Cinema integrators and playback vendors: cinema server, processor and loudspeaker manufacturers implement channel labeling to route audio correctly.
• Quality control and localization: QC teams, dubbing houses and localization engineers rely on standardized labels to verify channel placement and metadata.
• Accessibility workflows: hearing‑impaired and narration channels (HI, VI‑N) are defined to standardize delivery of accessibility audio.

Related standards

• ISO 26428‑1 (Image characteristics) and ISO 26428‑2 (Audio characteristics)
• SMPTE 428‑3‑2006 (origin standard)
• AES3 (digital audio serial format), AES31, ITU‑R BR.1384, SMPTE RP 173

ISO 26428‑3:2008 is essential for anyone involved in D‑cinema audio delivery who needs consistent, interoperable channel identification and routing across production, packaging and playback systems.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 26428-3
First edition
2008-09-01
Digital cinema (D-cinema) distribution
master —
Part 3:
Audio channel mapping and channel
labeling
Souche de la distribution du cinéma numérique (cinéma D) —
Partie 3: Cartographie de la chaîne sonore et marquage de la chaîne
sonore
Reference number
©
ISO 2008
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ii © ISO 2008 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 26428-3 was prepared by the Society of Motion Picture and Television Engineers (as
SMPTE 428-3-2006) and was adopted, under a special “fast-track procedure”, by Technical Committee
ISO/TC 36, Cinematography, in parallel with its approval by the ISO member bodies.
ISO 26428 consists of the following parts, under the general title Digital cinema (D-cinema) distribution
master:
⎯ Part 1: Image characteristics
⎯ Part 2: Audio characteristics
⎯ Part 3: Audio channel mapping and channel labeling

Introduction
This International Standard comprises SMPTE 428-3-2006 and the following informative note.
⎯ Informative reference: The French national standard NF S27-100, Cinematography — Electronic
projection rooms of digital cinema type, provides additional regional information.

iv © ISO 2008 – All rights reserved

SMPTE 428-3-2006
SMPTE STANDARD
D-Cinema Distribution Master
Audio Channel Mapping
and Channel Labeling
Page 1 of 9 pages
Table of contents
Foreword
Introduction
1 Scope
2 Normative reference
3 Definition of terms
4 Channel maps and labels
5 Channel labels — Supplemental channels
6 Information diagram (not to scale)
Annex A  Bibliography
Foreword
SMPTE (Society of Motion Picture and Television Engineers) is an internationally-recognized standards-
developing organization. Headquartered and incorporated in the United States of America, SMPTE has
members in over 80 countries on six continents. SMPTE’s engineering documents — including standards,
recommended practices, and engineering guidelines — are prepared by SMPTE’s technology committees.
Participation in these committees is open to all with a bona fide interest in their work. SMPTE cooperates
closely with other standards-developing organizations, including ISO, IEC, and ITU.

SMPTE engineering documents are drafted in accordance with the rules given in Section XIII of its
Administrative Practices.
SMPTE 428-3 was prepared by the Committee on Digital Cinema Technology (DC28).

Introduction
This channel-mapping and labeling scheme is specific to digital cinema while at the same time taking into
account historical practice and standards work of both SMPTE and ITU. Current systems and legacy systems
were taken into account.
1 Scope
This standard defines the mapping and labeling of channels for the Digital Cinema Distribution Master
(DCDM) audio in a digital cinema audio system to aid the identification and location of channels. This will
allow uniform expression and communication of source audio channels to digital cinema playback
loudspeakers. This standard is not intended to define the suitability of these channels for a particular sound
Approved
MOTION PICTURE AND TELEVISION ENGINEERS
September 29, 2006
3 Barker Avenue, White Plains, NY 10601
[phone]
SMPTE 428-3-2006
track nor to specify that all channels described herein will be used. It is quite likely however that additional
channels will be used in future systems; these are therefore included in this standard as labels only. Channel
maps define channel usage of common legacy systems.

2 Normative reference
The following document contains provisions which, through reference in this text, constitute provisions of this
recommended practice. At the time of publication, the edition indicated was valid. All standards are subject to
revision, and parties to agreements based on this practice are encouraged to investigate the possibility of
applying the most recent edition of the document indicated below.

AES3-2003, AES Recommended Practice for Digital Audio Engineering — Serial Transmission Format Two-
Channel Linearly Represented Digital Audio Data (Revision of AES3-1992)

3 Definition of terms
Left: A loudspeaker position behind the screen to the far left edge, horizontally, of the screen center as
viewed from the seating area.
Center: A loudspeaker position behind the screen corresponding to the horizontal center of the screen as
viewed from the seating area.
Right: A loudspeaker position behind the screen to the far right edge, horizontally, of the screen center as
viewed from the seating area.
LFE screen: A band-limited low frequency only loudspeaker position at the screen end of the room. Also
refered to as “the sub-woofer channel. “

Left surround: An array of loudspeakers positioned along the left side of the room starting approximately 1/3
of the distance from the screen to the back wall.

Right surround: An array of loudspeakers positioned along the right side of the room starting approximately
1/3 of the distance from the screen to the back wall.

Center surround: A loudspeaker(s) position on the back wall of the room centered horizontally.

Left center: A loudspeaker position mid-way between the center of the screen and the left edge of the
screen.
Right center: A loudspeaker position mid-way between the center of the screen and the right edge of the
screen.
LFE 2: A band-limited low frequency only loudspeaker.

Vertical height front: A loudspeaker(s) position at the vertical top of the screen. A single channel would be
at the center of the screen horizontally. Dual channels may be positioned at the vertical top of the screen and
in the left center and right center horizontal positions. Tri-cha
...