Captions
Captions are similar to subtitles, but also include sound effects etc
- Used for synchronised media, for example videos with visuals and sounds.
Synchronised visual text alternative for both speech and non-speech audio information.
Benefits: those who can’t hear, listen or understand audible information.
Added benefits
- Search engine optimization (SEO)
- Second language learners.
- The ability to watch or "listen to" video/audio with the sound off
Transcripts
For any content with audio
- Audio-only : podcasts
- Video with sound
Text based document including text descriptions of visual and auditory information. Similar to captions, transcripts capture both spoken words and other audio information. They should also include significant visual descriptions to provide as as much of an equivalent experience as possible for those who are unable to access the auditory and visual content.
The only means of access users who are deafblind have to this type of content.
Added benefits
- Browsing through information at your own pace
- Search through text and interact with text (copy and paste)
- SEO-friendly
Audio descriptions
Narration added to the soundtrack to describe important visual details that can’t be understood via the soundtrack.
The narrator speaks in the gap in the dialogue providing commentary to give people the context they need.
Sometimes need to pause the video to provide the narration.
Generally need to either be able to switch it on or off, or provide an alternative version.
Benefits: those who can’t see or look at the content.
Not needed if the audio is planned to include important information (eg video of talking heads)
Tips
- Try to plan the video to not need audio description
- Link to an alternative version with audio description
Other considerations with multimedia
Flashing visual effects in videos can cause seizures in some people.
Some people with vestibular disorders can become dizzy, nauseous, or disoriented when there is excessive motion in video or animated content.
Autoplaying should be avoided.
Audio should be clear, avoid loud background noises