ISO 26428-3:2008

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.