IEC 61937-5:2006

Overview

IEC 61937-5:2006 - "Digital audio - Interface for non-linear PCM encoded audio bitstreams applying IEC 60958 - Part 5" - defines how DTS (Digital Theater Systems) bitstreams are carried over IEC 60958 audio interfaces (e.g., S/PDIF, AES3). The standard covers DTS data‑types I, II, III and IV, specifying how frames are mapped into IEC 61937 data‑bursts, how burst‑info is encoded, and constraints needed for correct decoding and synchronization.

Key topics and technical requirements

• Scope and mapping: The coding of DTS bitstreams and data‑bursts follows IEC 61937‑1 and IEC 61937‑2 rules; IEC 61937‑5 adds DTS‑specific mappings.
• Burst‑info: A 16‑bit burst‑info field identifies the DTS data‑type and repetition period. Certain bits indicate the data‑type (I–IV) and for type IV the repetition period is dependent on bits 8–10.
• Data‑type identifiers: Examples in the standard: DTS type I uses data‑type value 0Bh; DTS type II uses 0Ch.
• Data‑burst format: Each data‑burst contains a burst preamble, burst payload and stuffing bits.
  • DTS type I: payload contains one complete DTS frame representing 512 samples per encoded channel.
  • DTS type II: payload contains one complete DTS frame representing 1 024 samples per channel.
• Pause data‑bursts: Recommended repetition period for pause data‑bursts is 3 IEC 60958 frames for all DTS types to fill stream gaps and maintain spacing.
• Reference points and timing: The standard specifies reference points (e.g., bit 0 of Pa) and repetition periods - critical for correct frame alignment and lip‑sync.
• Decoding latency: Shown per data‑type to allow transmitters to schedule bursts for picture/audio synchronization. Example: a DTS decoder latency example for type II is given as 768 PCM samples (≈16 ms at 48 kHz).

Applications and who uses it

• Consumer electronics manufacturers (Blu‑ray players, set‑top boxes, DVD players) to implement S/PDIF/AES3 output that carries DTS audio.
• AV receiver and decoder vendors to correctly detect and decode DTS bursts and handle latency/stream gaps.
• Firmware and hardware designers developing IEC 60958‑compliant transmitters and receivers for non‑linear PCM (compressed) audio.
• Test labs and interoperability engineers verifying compliance and stream timing (burst spacing, pause bursts, burst‑info correctness).
• Broadcasters and content distributors that need to transport DTS audio over digital audio interfaces while preserving synchronization.

Related standards

• IEC 61937‑1, IEC 61937‑2 (general mapping and burst‑info)
• IEC 60958‑1, ‑3, ‑4 (digital audio interface consumer/professional)
• Other IEC 61937 parts for AC‑3, MPEG, ATRAC, WMA professional

Keywords: IEC 61937-5, DTS bitstream, digital audio, IEC 60958, S/PDIF, AES3, burst-info, data-burst, non-linear PCM, audio latency.