ISO/IEC 23090-34:2025

Overview

ISO/IEC 23090-34:2025 specifies immersive audio reference software that accompanies the MPEG‑Immersive Audio specification (ISO/IEC 23090‑4). The document contains simulation and reference implementations - primarily a normative bitstream decoding and rendering implementation and an informative bitstream encoder - intended as a practical example and development starting point for compliant MPEG‑I immersive audio products.

Key topics and requirements

• Reference software derived from development reference models used while creating ISO/IEC 23090‑4.
• Bitstream decoding and rendering: a normative reference implementation that accepts ISO/IEC 23090‑4‑compliant bitstreams, decodes them and renders audio signals based on listener input (including support for 6DoF metadata). Build instructions and implementation details are provided in the renderer README.
• Bitstream encoding (informative): example encoder that produces compressed bitstreams using the normative syntax; encoding techniques, performance and complexity are not prescribed and the provided encoder is not fully optimized.
• Support files and formats:
  • Encoder Input Format (EIF) - describes input formats for the reference encoder.
  • Listener Space Information (LSI) - describes listening space metadata used by the renderer.
• Interoperability and compliance: the decoding software is considered a complying implementation of ISO/IEC 23090‑4, but other implementations need not follow its internal algorithms or programming techniques.
• Dependencies and audio coding: while metadata and rendering follow ISO/IEC 23090‑4, audio asset coding is based on ISO/IEC 23008‑3 (MPEG‑H 3D Audio).
• Licensing and copyright: source modules include copyright disclaimers and top‑level license files; software is provided as an electronic attachment and via the ISO standards website.

Applications

• Rapid prototyping and proof‑of‑concept implementations for immersive audio systems (VR/AR, games, live events, cinema, streaming).
• Interoperability testing, conformance checks and validation of ISO/IEC 23090‑4 compliant decoders and renderers.
• Reference for implementers to interpret ambiguous or complex aspects of the MPEG‑I immersive audio standard.
• Educational and research use in spatial audio, 6DoF rendering and immersive media processing.

Who should use this standard

• Audio codec and renderer developers building MPEG‑I immersive audio products.
• System integrators and platform providers implementing immersive audio playback.
• Content creators and tool vendors producing EIF streams or LSI metadata.
• Researchers and QA engineers performing testing, validation and performance comparisons.

Related standards

• ISO/IEC 23090‑4 - MPEG‑I Immersive Audio (normative reference).
• ISO/IEC 23008‑3 - MPEG‑H 3D Audio (used for audio asset coding).

Keywords: ISO/IEC 23090‑34:2025, immersive audio reference software, MPEG‑I immersive audio, bitstream decoding, bitstream encoding, EIF, LSI, 6DoF, MPEG‑H 3D Audio, reference implementation.