Overview
IEC 61937-17:2025 defines how to carry non-linear PCM audio bitstreams encoded in the AVS3-P3 format over the digital audio interface specified by IEC 60958. Part of the IEC 61937 series, this edition specifies the mapping, burst structure, timing and signalling required to transmit AVS3‑P3 frames as IEC 60958 data‑bursts so external decoders can recover and decode the audio reliably.
Key topics and technical requirements
- Data-type signalling: AVS3‑P3 is signalled as an extended data-type (bursts carry an extended preamble). The standard uses the extended data-type identifier for AVS3‑P3 to mark payload bursts.
- Frame sizes and sub-data-types: Two AVS3‑P3 frame length options are defined - frames based on 1 024 or 512 PCM samples - mapped to sub-data-type 0 and 1 respectively.
- One frame per burst: Each AVS3‑P3 data-burst shall contain one complete AVS3‑P3 frame; every frame must fit inside a single IEC 60958 data-burst.
- Repetition periods: Four repetition-period options are available for each frame length (e.g., 1 024, 4 096, 8 192, 16 384 IEC 60958 frames for the 1 024-sample mode) to accommodate different transport bandwidths.
- Sample rates and max data rate: The standard lists supported sample rates (32, 44.1, 48, 96 and 192 kHz) and how IEC 60958 frame rate maps to encoded sample rate and maximum available data rate.
- Pause bursts: A recommended pause data-burst repetition is specified (recommended 4 IEC 60958 frames) to fill stream gaps.
- Decoding latency and synchronization: Decoding latency is defined (receiver delay + decoding delay) and must be signalled/used by the transmitter to schedule bursts and maintain A/V sync.
- Operational guidance: The document recommends avoiding dynamic changes to repetition periods because such changes affect IEC 60958 frame rate and can cause temporary audio interruptions.
Applications and who uses this standard
- Manufacturers of digital audio interfaces, AV receivers, set-top boxes and soundbars that need to transport AVS3‑P3 encoded audio over IEC 60958 streams.
- Codec and firmware developers implementing AVS3‑P3 encoders/decoders and burst-payload formatting.
- Broadcasters, content distributors and system integrators specifying transport timing and bandwidth allocation for compressed audio.
- Compliance engineers and test labs validating IEC 61937 interoperability and timing (burst structure, repetition, latency).
Related standards
- IEC 61937-1:2021 - Digital audio interface general mapping and preamble rules (normative reference).
- IEC 60958 - Digital audio interface physical/frame definitions used for burst transport.
Keywords: IEC 61937-17, AVS3-P3, IEC 60958, non-linear PCM, digital audio interface, data-burst, burst-info, repetition period, decoding latency, audio frame.