Mobile Accessibility Guidelines - Audio & Video

Audio conflict should not

Narrative audio in games or interactive media should not talk over or conflict with native assistive technology.

In order to interact with embedded media, users need to perceive the editorial narrative and/or instructions.

If the embedded media is self-voicing content, this should be hidden from the screen reader. If the embedded media is providing content to the screen reader, then this should not be self-voicing.

Note: Further research is currently being conducted to ascertain user preferences.

iOS

Use the UIAccessibilityTraitStartsMediaSession trait to silence VoiceOver while a user is playing or recording audio.

Use this attribute with care: some situations may require VoiceOver speech during a media session - for example, to indicate how much time is left for a particular task.

iOS Example (Objective-C)

var button = UIButton(type: .system)

button.accessibilityTraits |= UIAccessibilityTraitStartsMediaSession

Android

By default, audio from the TalkBack screen reader will take precedence over all other forms of audio output on an Android device.

HTML

By default, both TalkBack and VoiceOver audio will take precedence over all other forms of audio output (such as a YouTube video), when that audio is embedded in an HTML page.

Testing

Procedures

  1. Locate media.
  2. Enable screen reader.
  3. Ensure screen reader can be heard and does not clash unnecessarily with any audio in the media.

Outcome

The media does not conflict with the volume of the screen reader.