ISO/IEC 23009-2:2020

Overview - ISO/IEC 23009-2:2020 (DASH)

ISO/IEC 23009-2:2020, "Information technology - Dynamic adaptive streaming over HTTP (DASH) - Part 2: Conformance and reference software," specifies the conformance rules and reference implementations used to validate media presentation descriptions (MPDs), media segments and their combinations defined in ISO/IEC 23009‑1. This third-edition standard provides test vectors, software modules and validators to ensure DASH deployments meet the DASH specification and interoperate across players, servers and networks.

Key topics and requirements

• MPD conformance: Rules and software for checking static and dynamic MPDs, including XLink resolution and XML schema validation (see Annex A for detailed checks).
• Segment conformance: Validators for segment formats referenced in MPDs, covering ISO Base Media File Format (ISO BMFF) and MPEG-2 Transport Stream (MPEG-2 TS), representation and adaptation set conformance.
• Dynamic services: Conformance tools and a dynamic media presentation emulator for testing live and time-varying DASH behaviors.
• Profiles and feature coverage: Profile-specific conformance (on-demand, live, main, MPEG-2 TS simple) and coverage information (Annex E).
• Server and network-assisted DASH (SAND): Test vectors, conformance rules and reference clients/servers for ISO/IEC 23009‑5 features (HTTP and WebSocket SAND).
• Server push (23009-6): Reference tools and utilities (e.g., ABNF validation) to support server push workflows.
• Reference software: Includes MPD conformance software, ISO BMFF and MPEG-2 TS validators, libdash (DASH access engine), example systems and sample packages (Annex C). Software and test vectors are publicly available from the ISO site.

Practical applications - who uses it and why

• Streaming service providers and CDNs use the standard to validate MPDs and segments before deployment to ensure consistent playback and adaptive behavior across devices.
• Player and client developers (including SDK vendors) rely on reference software and libdash examples for implementation guidance and interoperability testing.
• Encoder/packager vendors use segment validators (ISO BMFF / MPEG-2 TS) to ensure produced segments conform to DASH requirements.
• Test labs and QA teams perform conformance testing with the provided test vectors and dynamic emulators to certify devices and services.
• Standards and research organizations use the reference implementations to clarify and validate DASH specifications.

Related standards and resources

• ISO/IEC 23009-1 (DASH MPD and segment formats)
• ISO/IEC 23009-5 (SAND) and ISO/IEC 23009-6 (Server push)
• ISO 8601-1 (date/time representation) and IETF RFC 7233 (HTTP range requests)
• Reference software and test vectors: https://standards.iso.org/iso-iec/23009/-2/ed-3/en

This standard is essential for reliable DASH conformance testing, interoperability validation, and reference implementations across the streaming ecosystem.