Overview
ISO 26428-9:2009 (equivalent to SMPTE 428-9-2008) is part of the D‑Cinema Distribution Master (DCDM) suite. It specifies the level 3 image pixel structure formatting and constraints for transmission over Serial Digital Interface (SDI) links - specifically the 1.485 Gb/s dual‑link SDI (SMPTE 372M) and the single 3 Gb/s SDI (SMPTE 424M). The standard defines how a 2048 × 1080 DCDM image is packed into an SDI container, synchronization signaling, ancillary data use, and constraints on pixel code values and blanking.
Key topics and requirements
- SDI container and pixel array
- Fixed SDI container sized for a 2048 × 1080 pixel array (DCDM Level 3).
- Active image centered in the container; unused pixels are padding and shall be set to 0x010 (black).
- Sampling parameters include 24 Hz frame rate and a reference sampling frequency (fs) of 74.25 MHz for the specified mapping.
- Pixel coding
- Image channels are three parallel data channels X′, Y′, Z′ following the DCDM image pixel structure as defined in SMPTE 428‑1.
- Payload shall avoid certain reserved code ranges (the standard prohibits ranges such as 0x000–0x00F and 0xFF0–0xFFF in the payload).
- Values outside defined limits in the source signal must be clipped.
- Serial line framing and sync
- Use of standard SDI digital synchronizing sequences: SAV (Start of Active Video) and EAV (End of Active Video) - each is a 4‑word sequence (all‑ones, two all‑zeros, then a timing word with F/V/H/P bits).
- The interface frame contains 1125 total lines, with the 1080 active image lines mapped to lines 42–1121.
- Special handling for Progressive Segmented Frame (PsF) systems is specified (line numbering and F/V bit assignment).
- Ancillary data (ANC)
- ANC packets may be carried in blanking intervals (HANC/VANC) per SMPTE 291M.
- ANC words use the 10 most significant bits of the 12‑bit sample (LSB 2 bits set to zero).
- Unused blanking intervals shall carry the black codeword (0x010).
Applications and users
- Post‑production and digital cinema mastering facilities creating DCDM packages for theatrical distribution.
- Manufacturers of SDI encoders/decoders, video servers, routers, and digital cinema playback servers/projectors.
- Systems integrators and QA engineers validating SDI transport compliance for D‑cinema workflows.
- Broadcast and mastering engineers implementing 2K/2048×1080 DCP (distribution master) ingest/export over SDI.
Related standards
- SMPTE 428‑1 (DCDM Image Characteristics) - defines X′Y′Z′ pixel coding referenced here.
- SMPTE 291M (Ancillary Data Packet Formatting) - ANC packet structure used in SDI blanking.
- SMPTE 372M (dual‑link 1.485 Gb/s mapping) and SMPTE 424M (3 Gb/s mapping) - SDI interfaces referenced for transport.
Keywords: ISO 26428-9:2009, SMPTE 428-9, D‑cinema distribution master, SDI, 2048×1080, X′Y′Z′, SAV/EAV, ancillary data, PsF, SMPTE 372M, SMPTE 424M.
Open preview (PDF)Digital cinema (D-cinema) distribution master — Part 9: Image pixel structure level 3 — Serial digital interface signal formatting
