ISO/IEC 23000-22:2025

Overview

ISO/IEC 23000-22:2025 - Multi-Image Application Format (MIAF) specifies a constrained, interoperable way to store multiple images, image groups and image sequences with their metadata inside the High Efficiency Image File (HEIF) container. MIAF refines ISO/IEC 23008-12 (HEIF) by defining additional constraints, specific alpha plane formats, profiles and levels for coding formats, metadata formats, and a set of brands to signal conformance. The standard also defines normative behaviour for a MIAF reader and MIAF renderer, and is intentionally extensible to support forward compatibility and optional additional data.

Keywords: ISO/IEC 23000-22:2025, MIAF, HEIF, multi-image, metadata, interoperability, alpha plane, profiles, brands

Key Topics and Requirements

• Interoperability constraints: MIAF narrows HEIF options to create precise, interoperable implementation points for capture, editing, storage and playback.
• File structure rules: Defines box-level, item-level and track-level requirements to ensure consistent parsing of images, thumbnails, auxiliary images, derived images and sequences.
• Alpha plane formats: Specifies supported alpha/opacity plane encodings for compositing and transparency use cases.
• Profiles and levels: Declares a set of supported coding formats (profiles/levels) to guarantee decoder compatibility across devices and services.
• Metadata formats: Standardizes metadata types and structures to ensure consistent interpretation of color, HDR signalling, mastering display data and other descriptive attributes.
• Brands and file signaling: Introduces brands (including application brands) that indicate conformance to MIAF profiles and capabilities.
• Extension rules: Provides rules for adding new coding formats, profiles, levels and metadata while preserving forward compatibility.
• Normative behaviours: Defines how a MIAF reader should parse files and how a MIAF renderer should present or decode image content.

Practical Applications

MIAF is designed for industries and tools needing consistent multi-image handling and interoperability:

• Digital camera manufacturers and smartphone OEMs - for capture, burst, HDR and multi-layer images.
• Image editing and creative software - for preserving derived images, alpha channels and metadata across workflows.
• Cloud storage and CDN providers - for reliable delivery and transcoding of multi-image assets.
• Web and media playback platforms - for consistent rendering of rich image collections, thumbnails and sequences.
• Archival and content-management systems - for standardized metadata and long-term accessibility.

Keywords: image workflows, HEIF container, MIAF reader, MIAF renderer, image interoperability

Related Standards

• ISO/IEC 23008-12 (HEIF) - underlying file format specification.
• ISO/IEC 23000 (MPEG-A) series - multi-part multimedia application formats.