Some users cannot hear the dialogue or sound effects clearly or at all.


Provide an alternative for the dialogue and sound effects

Who does it impact:

This affects people with hearing loss or deafness. It also happens to people in a noisy place where it is hard to hear, or a quiet pace where you cannot turn up the sound.

How does it impact them?

Ways to solve the problem:

Provide the dialogue and describe the sound effects in text, sign language or the pictures.

Provide text that shows what is being said.

Captions are text that appears on the screen, providing the text of what is being said. They can also provide a text version of sound effects. They enable people to read the dialogue instead of listening.

Most video players have built-in captioning systems. The video needs to have captions@@.

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Writing HTML

The captions can be linked to the video using the HTML video and source elements.

<video src="fancyVid.mp4">
  <track src="captions.vtt" kind="captions">

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Using A third-party tool like Youtube to manage videos

For a youtube video, captions be provided as a ... file when the video is uploaded. Ther is also an automatic captioning feature - but the quality is not always good.

This will not help people who cannot read fast enough to keep up, unless they can slow down or pause the video.

Captions can be hard to read, if they are on the picture and do not stand out clearly enough.

Captions on the screen cannot be read by people who cannot see clearly. Caption formats that can be presented as text can still be made available, e.g. through braille or through some other interface.

Reading captions can distract people from seeing the video. Then they may miss important parts.

Provide sign language interpretation of what is being said.

Sign language videos can be played alongside, or inside, a video

Show in the pictures what is being said.

Make sure you don't need sound to understand the video.

Show things that sound effects communicate.

Testing if the problem is solved

Can the user use the alternative provided?

To test the solution:

Turn off your sound and watch the video. Do you understand it?
Do you understand it? If you do, you're done. Otherwise...
Can you turn on captions and watch the video?
Do you understand it now? If so, you're done. Otherwise

To test the solution

  1. If you can understand the video with the sound turned off, it passes.
  2. If not, can you turn on the captions and watch the video? If you understand it with captions turned on:
    • Your captions pass. You will still need to test whether they cause other problems (contrast is poor, distracting, ...)

Issues under discussion:

Is it always necessary to caption sound?

For example, where there is a background of birds singing, in a video of a nature scene, are captions necessary or not?