Checkpoint 10.2.40 Audio Description Timing

Where ICT is a non-web document that contains synchronized media with audio description, the audio description should not interfere with relevant audio information in the synchronized media.


The European standard contains a requirement that audio descriptions not overlap with any meaningful information on the audio track. This requirement only applies to non-web documents.

A similar Web Content Accessibility Guidelines (WCAG) principle exists for all audio descriptions, so any team following best practices will not need to do additional work to meet this. As it notes in each of the WCAG general techniques for audio descriptions:

"Since it is not helpful to have this new information obscure key audio information in the original sound track (or be obscured by loud sound effects), the new information is added during pauses in dialogue and sound effects."

Refer to Requirement 10.2.40: Audio Description Timing for more information (external link to EN 301 549 toolkit).

Note: The IBM compliance reporting system will be able to convey compliance status with European EN 301 549/Mandate 376: Accessibility requirements suitable for public procurement of ICT products and services in Europe. IBM accessibility checkpoints for the Revised Section 508 standard cover most of the EN 301 549 requirements. However, this is one of a set of additional checkpoints that must be completed to fully report compliance with the European standard.

Development Techniques

Note: Review the General techniques as well as other tabs applicable to your technology.  Prioritize the use of technology-specific techniques, and implement the General techniques as needed. You are always required to find, understand and implement accessible code techniques to meet the checkpoint. The documented techniques and supplements are not exhaustive; they illustrate acceptable ways to achieve the spirit of the checkpoint. If numbered, techniques are in order of preference, with recommended techniques listed first.

General techniques

Ensure audio descriptions to do not overlap dialogue or other important information by using any of the following general techniques provided for Checkpoint 1.2.5 Audio Description (Prerecorded).

Mobile Native (iOS) techniques

There are no specific Mobile Native techniques for this checkpoint. Refer to the General techniques section.

Eclipse techniques

There are no specific Eclipse techniques for this checkpoint. Refer to the General techniques section.

Windows-based (MSAA+IA2) techniques

There are no specific Windows-based (MSAA+IA2) techniques for this checkpoint. Refer to the General techniques section.

Many links in this checklist reside outside at the Web Content Accessibility Guidelines (WCAG) 2.1. W3C Recommendation 05 June 2018:

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