ISO IEC 23003-5-2020 PDF

Full title and description

ISO/IEC 23003-5:2020 — Information technology — MPEG audio technologies — Part 5: Uncompressed audio in MPEG‑4 file format. Defines the representation and storage of uncompressed (LPCM and floating point) audio in files based on the ISO Base Media File Format (commonly used by MP4), including mono, stereo and multi‑channel arrangements and guidance on related metadata and container mapping.

Abstract

This document defines how uncompressed audio is carried in files in the family of standards based on the ISO base media file format. It covers mono, stereo and multi‑channel Linear PCM (LPCM) with various word lengths and sampling rates and floating point formats, and notes that similar representations occur in other container formats such as RIFF WAV or AIFF.

General information

• Status: Published.
• Publication date: January 2020.
• Publisher: ISO/IEC (ISO and IEC, joint publication).
• ICS / categories: 35.040.40 (Coding of audio, video, multimedia and hypermedia information).
• Edition / version: Edition 1 (2020-01).
• Number of pages: 3 pages.

Basic bibliographic and lifecycle details as published by ISO/IEC JTC 1/SC 29.

Scope

The standard specifies the mapping and storage of uncompressed audio sample data (LPCM and floating point) into the ISO Base Media File Format (the basis of MP4 family files). It addresses channel configurations (mono through multi‑channel), permitted sample rates and word lengths, representation of sample formats, and how these representations relate to other common container formats such as WAV and AIFF. The scope is narrowly focused on transport/packaging of uncompressed audio within ISO base media file format containers rather than on coding or compression algorithms.

Key topics and requirements

• Specification of how PCM and floating point audio samples are represented and stored inside ISO base media file format boxes/atoms.
• Channel mapping and support for mono, stereo and multi‑channel configurations.
• Support and constraints for sampling rates and word lengths (various bit depths) and floating point sample formats.
• Guidance on metadata and container-level descriptors required to identify uncompressed audio streams within MP4-family files.
• Notes on compatibility/relationship with other containers (e.g., RIFF WAV, AIFF) that use similar uncompressed representations.
• Interoperability considerations for implementers packaging or parsing uncompressed audio in MPEG/MP4 ecosystems.

Typical use and users

Implementers of media players, MP4 packagers and muxers, digital audio workstation (DAW) and authoring tool vendors, broadcast and streaming platform engineers, device manufacturers and test labs use this standard to ensure consistent storage and interchange of uncompressed audio in MP4‑family files. It is primarily a packaging/interchange specification rather than an encoding standard.

Related standards

Part 5 is one element of the ISO/IEC 23003 (MPEG‑D) series covering MPEG audio technologies. Related parts include: Part 1 (MPEG Surround), Part 2 (Spatial Audio Object Coding), Part 3 (Unified speech and audio coding), Part 4 (Dynamic Range Control), and additional parts addressing reference software and conformance testing. For the series and current part listings see ISO/IEC JTC 1/SC 29 and MPEG program documentation.

Keywords

MPEG, MPEG‑D, ISO base media file format, MP4, uncompressed audio, LPCM, PCM, floating point audio, container mapping, channel mapping, audio interchange.

FAQ

Q: What is this standard?

A: ISO/IEC 23003-5:2020 is an international standard that specifies how uncompressed audio (PCM and floating point samples) is carried inside files based on the ISO base media file format (MP4 family).

Q: What does it cover?

A: It covers representation and packaging of uncompressed audio sample data in ISO base media file format containers, including channel configurations, sample formats (bit depths and floating point), sampling rates and related container descriptors; it does not define compression algorithms.

Q: Who typically uses it?

A: Software vendors (muxers, players, authoring tools), hardware manufacturers, broadcasters, streaming platforms and test laboratories use it to ensure interoperable storage and exchange of uncompressed audio in MP4‑family files.

Q: Is it current or superseded?

A: The standard was published in January 2020 and is listed as Published by ISO; as of its publication it is the current edition (Edition 1, 2020). ISO standards are reviewed on a regular schedule; check ISO/IEC JTC 1/SC 29 for any later revisions.

Q: Is it part of a series?

A: Yes — it is Part 5 of the ISO/IEC 23003 (MPEG‑D) series of MPEG audio technologies; other parts address surround, spatial object coding, unified speech/audio coding, dynamic range control, and related reference and conformance documents.

Q: What are the key keywords?

A: MPEG, ISO base media file format, MP4, LPCM, PCM, uncompressed audio, channel mapping, container, MP4 packaging.