Updated DASH Conformance Software brings new validation features
Version 3.1.0 of the open-source DASH Conformance Software has been released, bringing a number of improvements that will be useful to developers building and testing MPEG-DASH streaming services, including those targeting HbbTV devices.
The conformance software was originally developed through the DASH Industry Forum (DASH-IF) to provide tools for checking MPEG-DASH content against relevant specifications and interoperability requirements. The open-source project continues to be developed, with this latest update funded by the DVB Project and other industry organisations. The software remains available through the existing DASH-IF Conformance repository on GitHub.
Importantly for HbbTV developers, the software goes beyond validation against the core MPEG-DASH specifications and includes checks relevant to related standards and profiles, including CMAF, DVB-DASH and HbbTV.
Version 3.1.0 introduces several significant updates, including the return of XSD-based manifest validation, support for directly entering MPD content, updates for the 3rd Edition of CMAF and improved support for $Number$ templates used with SegmentTimeline. The release also includes improvements to Docker deployment and internal error handling.
The new version was released on 10 September 2026, immediately ahead of IBC 2026.
Why conformance validation matters
MPEG-DASH gives streaming services considerable flexibility in how content, representations, segments and manifests are constructed. However, content that works successfully with one player or device may expose interoperability problems when deployed across a wider range of television receivers.
This is particularly relevant to HbbTV applications, where developers need to support an installed base of televisions from multiple manufacturers and model years.
Validation can therefore form an important part of the development and testing process. Rather than discovering problems only when content reaches a particular television or player implementation, developers can use conformance tools to identify potential problems with the MPD and associated media earlier in the workflow.
The DASH validator provides a common tool for performing these checks and can be used alongside testing on representative HbbTV devices.
XSD-based manifest validation reimplemented
One of the most significant changes in version 3.1.0 is the reimplementation of XSD-based manifest validation. The XML Schema Definitions (XSDs) used by the validator have also been updated to their latest versions.
An MPEG-DASH Media Presentation Description (MPD) is an XML document describing the structure of a presentation, including information about periods, adaptation sets, representations and the location and timing of media segments.
XSD validation checks the structure of this XML against the relevant schema. It can therefore identify structural errors, invalid attributes or elements and other problems that do not conform to the expected DASH manifest structure.
For developers, this provides a useful first level of validation before the additional DASH, DVB-DASH, HbbTV or other applicable conformance checks are considered.
Paste MPD content directly into the validator
Version 3.1.0 also makes a small but useful improvement to the way developers can use the tool: the input field can now accept MPD content directly.
This can simplify development and debugging. Instead of making a manifest available through a URL before it can be tested, developers can paste MPD XML directly into the validator.
That is particularly convenient when investigating a specific manifest problem, experimenting with changes to an MPD or validating content that is still within a development environment.
CMAF 3rd Edition updates
The release also updates various parts of the validator’s CMAF module to reflect the 3rd Edition of CMAF.
The Common Media Application Format (CMAF) provides a common fragmented MP4-based media format intended to improve interoperability and reduce the need to create multiple versions of the same media for different streaming environments.
For HbbTV services using CMAF-based content, keeping validation tools aligned with the evolving specification helps developers check their content against current requirements rather than older interpretations of the standard.
Better support for $Number$ with SegmentTimeline
Another change particularly relevant to manifest processing is improved support for $Number$ templates when used with SegmentTimeline.
DASH provides different mechanisms for describing how individual media segments can be located. Segment templates can construct segment URLs dynamically, with $Number$ allowing the segment number to form part of the URL.
SegmentTimeline, meanwhile, explicitly describes the timing and duration of media segments. Supporting the combination correctly is important for services using these mechanisms to describe their media presentation.
The improved validator support should make it easier to check streams using this form of DASH manifest construction.
Docker and error-handling improvements
There are also improvements for developers operating the validator itself.
Version 3.1.0 fixes issues with the project’s Docker build file, making container-based deployment more reliable. The release also improves internal error handling within the validator.
The Docker improvements are particularly useful for organisations wanting to incorporate conformance validation into their own development or test environments rather than relying solely on the publicly hosted instance.
Using the DASH Conformance Software
DASH-IF provides a hosted version of the latest stable Conformance Software, as well as a staging instance containing the current development version. The complete source code is also available from the project’s GitHub repository, allowing developers to install and run the validator within their own environments.
For media workflow developers, the tool can be useful at several stages of development: when initially preparing DASH content, when diagnosing playback problems, when introducing new encoding or packaging workflows, and as part of regression or automated testing.
It is worth remembering that conformance validation and testing on real receivers serve complementary purposes. Passing automated conformance checks does not guarantee that content will behave identically across every television implementation, but it can eliminate many content and manifest problems before device testing begins.
Version 3.1.0 therefore provides developers with an updated and more convenient tool for checking DASH services as part of a broader interoperability testing workflow.
Resources
The DASH Conformance Software repository contains the source code, installation information and documentation.
Full details of the changes are available in the DASH Conformance Software v3.1.0 release notes.
Developers can also use the hosted DASH Conformance Validator to test content against the latest stable release.
