IEC 61937-15:2021

Overview - IEC 61937-15:2021 (Auro‑Cx)

IEC 61937-15:2021 specifies how to convey non-linear PCM audio bitstreams formatted in the Auro‑Cx codec over the IEC 60958 digital‑audio interface. It defines the burst mapping, burst‑info fields and data‑burst formats required to transport Auro‑Cx blocks (audio data + metadata) so that connected devices (for example set‑top boxes, smart TVs and AV receivers) can exchange an Auro‑Cx bitstream reliably via IEC 60958 interfaces.

Keywords: IEC 61937-15, Auro‑Cx, IEC 60958, digital audio, non-linear PCM, Auro-3D.

Key topics and technical requirements

• Scope: Method for conveying Auro‑Cx non‑linear PCM bitstreams mapped to the IEC 61937 series.
• Burst mapping: A 16‑bit burst‑info word carries the data‑type and subdata‑type metadata required by IEC 61937‑1/‑2.
• Data‑burst formats: Defines pause data‑bursts and multiple Auro‑Cx audio data‑burst variants:
  • ACX (base)
  • ACX HBR2, HBR4, HBR8 (High Bit Rate variants)
• Timing and repetition: Repetition periods, maximum burst lengths and fractional frame‑rate handling (supporting common fractional rates such as 23.976, 29.97, 47.972, 59.94, 119.88 fps).
• Latency definitions: Specifies how to represent and account for decoder latency (receiving + decoding delay) and timing relationships between bursts and frames.
• Sample rates: Auro‑Cx supports sample rates up to 96 kHz; IEC 61937‑15 maps these high sample rates to appropriate IEC 60958 frame rates.
• Normative references: Requires use of IEC 60958 (digital audio interface) and IEC 61937 parts 1 and 2.

Practical applications

• Ensures interoperability between streaming sources (set‑top boxes, smart TVs, media players) and A/V decoders/receivers that decode Auro‑Cx.
• Guides firmware and hardware implementers on how to encapsulate Auro‑Cx bitstreams into IEC 60958 bursts for transmission over consumer/professional digital audio links.
• Provides test labs and QA teams with timing, burst and latency criteria needed for conformance testing and debugging of Auro‑Cx transmission.
• Useful for content distributors and integrators deploying immersive Auro‑3D/Auro‑Cx audio workflows in consumer electronics and streaming ecosystems.

Who should use this standard

• Audio firmware/hardware engineers, AV receiver and streamer manufacturers, codec implementers, test laboratories, system integrators and standards compliance teams working with Auro‑Cx or IEC 60958 transport.

Related standards

• IEC 60958 - Digital audio interface (physical / frame format)
• IEC 61937‑1:2021 - General mapping rules for non‑linear PCM bitstreams
• IEC 61937‑2:2021 - Burst information and common mechanisms

This standard provides the technical rules required to reliably pass Auro‑Cx immersive audio over IEC 60958 interfaces, enabling compatible devices to recognise, time and decode Auro‑Cx bitstreams for immersive playback.