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
This standard is essential for reliable DASH conformance testing, interoperability validation, and reference implementations across the streaming ecosystem.
Open preview (PDF)Information technology — Dynamic adaptive streaming over HTTP (DASH) — Part 2: Conformance and reference software
