ISO 26428-2:2008
(Main)Digital cinema (D-cinema) distribution master - Part 2: Audio characteristics
Digital cinema (D-cinema) distribution master - Part 2: Audio characteristics
ISO 26428-2:2008 addresses the interoperability of digital cinema equipment used to create an audio digital cinema distribution master, by defining bit depth, sample rate, minimum channel count and reference levels.
Souche de la distribution du cinéma numérique (cinéma D) — Partie 2: Caractéristiques d'écoute
General Information
Overview
ISO 26428-2:2008, titled Digital Cinema (D-cinema) Distribution Master – Part 2: Audio Characteristics, is an international standard developed by ISO in collaboration with the Society of Motion Picture and Television Engineers (SMPTE). This standard specifies the essential digital audio parameters ensuring interoperability of digital cinema equipment involved in creating Audio Digital Cinema Distribution Masters (DCDM). Key audio characteristics covered include bit depth, sample rate, minimum channel count, and reference levels, providing a unified basis for high-quality digital cinema audio delivery.
Key Topics
ISO 26428-2:2008 defines the following critical parameters for digital cinema audio mastering:
- Bit Depth: The maximum bit depth is 24 bits per audio sample, using a linear 2’s complement representation. This ensures high-resolution audio data for precise sound reproduction.
- Sample Rate: The audio sample rate must be either 48 kHz or 96 kHz, regardless of image frame rate. Maintaining these standardized sampling frequencies facilitates consistent audio playback fidelity across theaters.
- Channel Count: Supports up to sixteen full-bandwidth audio channels. Titles may use fewer channels depending on their audio mix, allowing for multi-channel surround sound and immersive audio experiences.
- Reference Level: Digital audio inputs and outputs use a nominal reference level of –20 dB FS (decibels relative to full scale) to standardize loudness levels and avoid distortion or clipping during playback.
These parameters align with AES3 digital audio transmission format recommendations, promoting compatibility across digital cinema workflows and equipment.
Applications
ISO 26428-2:2008 is essential for:
- Digital Cinema Audio Production: Audio engineers and post-production professionals use this standard to deliver compliant audio masters for distribution.
- Cinema Equipment Manufacturers: Ensures digital cinema playback systems, including servers, processors, and projectors, handle audio data consistently for seamless exhibition.
- Content Distributors: Facilitates standardized audio masters that can be reliably played in theaters worldwide, maintaining artistic intent and audio quality.
- Quality Assurance: Allows cinema chains and technicians to verify audio characteristics meeting international standards, improving audience experience.
By following ISO 26428-2, stakeholders guarantee high-fidelity, multi-channel digital audio infrastructure that supports immersive and reliable cinema sound.
Related Standards
ISO 26428-2:2008 complements the other parts of the ISO 26428 series addressing digital cinema distribution masters:
- ISO 26428-1:2008 – Image characteristics focusing on video parameters for digital cinema content.
- ISO 26428-3:2008 – Audio channel mapping and labeling defining standardized channel assignments for multi-channel audio formats.
Additionally, this standard references and aligns with key audio engineering guidelines from the AES (Audio Engineering Society) including:
- AES3-2003 – Serial transmission format for digital audio data.
- AES5-2003 – Preferred sampling frequencies for professional audio.
- AES11-2003 – Synchronization of digital audio equipment.
These related standards and recommended practices help form a comprehensive framework for the creation, transmission, and playback of high-quality digital cinema audio.
Keywords: ISO 26428-2, digital cinema audio standard, D-cinema distribution master, digital audio characteristics, cinema audio interoperability, 24-bit audio, 48 kHz sampling rate, 96 kHz sampling rate, multi-channel cinema sound, SMPTE 428-2, AES3 digital audio, cinema audio reference level, digital cinema audio mastering.
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 26428-2
First edition
2008-07-15
Digital cinema (D-cinema) distribution
master —
Part 2:
Audio characteristics
Souche de la distribution du cinéma numérique (cinéma D) —
Partie 2: Caractéristiques d'écoute
Reference number
©
ISO 2008
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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.
ISO 26428-2 was prepared by the Society of Motion Picture and Television Engineers (as
SMPTE 428-2-2006) 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
SMPTE 428-2-2006
SMPTE STANDARD
D-Cinema Distribution Master —
Audio Characteristics
Page 1 of 3 pages
Table of contents
Foreword
Introduction
1 Scope
2 Normative references
3 Parameter values
Annex A Bibliography
Foreword
SMPTE (the Society of Motion Picture and Television Engineers) is an internationally-recognized standards
developing organization. Headquartered and incorporated in the United States of Amer
...
Frequently Asked Questions
ISO 26428-2:2008 is a standard published by the International Organization for Standardization (ISO). Its full title is "Digital cinema (D-cinema) distribution master - Part 2: Audio characteristics". This standard covers: ISO 26428-2:2008 addresses the interoperability of digital cinema equipment used to create an audio digital cinema distribution master, by defining bit depth, sample rate, minimum channel count and reference levels.
ISO 26428-2:2008 addresses the interoperability of digital cinema equipment used to create an audio digital cinema distribution master, by defining bit depth, sample rate, minimum channel count and reference levels.
ISO 26428-2:2008 is classified under the following ICS (International Classification for Standards) categories: 35.040 - Information coding; 35.040.40 - Coding of audio, video, multimedia and hypermedia information; 37.060.99 - Other standards related to cinematography. The ICS classification helps identify the subject area and facilitates finding related standards.
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