Audio description is provided for all prerecorded video content in synchronized media.
Provide a synchronized spoken description of the visual content in videos.
Helps people who are blind or have low vision understand the visual content.
Audio description is very often missing.
If there is an audio description: Compare the audio description to the media content and ensure the description is descriptive enough.
If there is no audio description, check the video to see if the audio content actually is clear enough and if all necessary information is provided by the default audio track.
This also relates to criterion 1.2.3. An audio description will meet the requirements for that criterion as well.