Hi everyone!
Today we're tackling an increasingly relevant aspect of web accessibility: multimedia content. With the growing prevalence of videos and audio, it's crucial to ensure they are accessible to everyone. This topic focuses on WCAG requirements related to time-based media (primarily video and audio), covered under Principle 1.2 (Time-based Media).
Why is Multimedia Content Accessibility Crucial?
Inaccessible multimedia content can exclude:
- Deaf or Hard of Hearing Individuals: Without captions or transcripts, they cannot access audio content.
- Blind or Low Vision Individuals: Without audio descriptions or transcripts, they cannot access visual content.
- Individuals with Cognitive Disabilities or Learning Difficulties: Transcripts and captions can aid comprehension.
- Users in Quiet/Noisy Environments: Allows content consumption without audio or with reduced audio.
Here are the main success criteria to consider:
1. 1.2.1 Audio-only and Video-only (Prerecorded) - Level A:
- Audio-only: Provide a transcript or equivalent text alternative.
- Video-only: Provide a text description or an audio track that describes what is happening visually.
- Provide synchronized captions for all prerecorded audio content in video. Captions must include both speech and relevant non-speech sounds.
- Video: Provide a prerecorded audio description for video content, or an alternative for time-based media that includes audio description. Audio description narrates important visual elements when there is no dialogue.
- For live audio content in video, provide synchronized captions. This is more challenging and often requires professional services.
- For prerecorded video content, provide detailed audio description.
- Captions:
- Synchronized with the audio.
- Include both speech and relevant environmental sounds (e.g., [upbeat music], [applause]).
- Can be closed (CC - user activates them) or open (OC - always visible). Prefer closed for user choice.
- Transcripts:
- Full text of all dialogue and relevant sounds, in chronological order.
- Useful for those who cannot play audio/video or prefer to read.
- Must be easily accessible (e.g., a link below the video).
- Audio Descriptions:
- Narrate important visual elements (actions, expressions, on-screen text) during pauses in dialogue.
- Can be integrated into the main audio track or be a separate track.
- Player Controls: Ensure that the multimedia player controls themselves are keyboard and screen reader accessible (WCAG 2.1.1 and 4.1.2).
What are your experiences with creating accessible multimedia content? Do you have preferred tools or services for generating captions or audio descriptions? What challenges have you encountered, especially with live content?
Warm regards,
Michele (wcgadmfrm)
WCAG Plus Forum Team