Media files make it possible for the information to be transferred quickly and easily. To make them accessible to everyone, it must be ensured that visitors can experience films and sound fragments with the senses available to them. Visitors who are deaf or hard of hearing cannot hear (clearly) what is being said in a sound fragment. Visitors who are blind or visually impaired cannot see what is shown in a video. Therefore, add an alternative way of communication, such as subtitles, a transcript or an audio description.

The guidelines distinguish between different forms of audio and video:

  • Sound fragments (sound without image)
  • Moving pictures (picture without sound)
  • Movies (image with sound)

Sound fragments or video are sometimes used as an alternative to text. If all the information that can be seen or heard is also available in the text, then you speak of a media alternative. With an equivalent media alternative, a media file does not have to meet the associated requirements such as subtitles, transcript or audio description.

In the Netherlands an exception applies to media published before September 23, 2020. Live media does not have to be directly accessible either. If it is available online after the broadcast or is republished somewhere else, then it must be made accessible.

  • All media files must have a brief textual introduction, even if full alternatives such as a transcript or audio description are available. Such a short introduction should roughly describe the contents of the media file. With this information, visitors can decide for themselves what they want to do with the media file. This is especially useful to visitors who cannot easily scan the content, such as visitors who use screen readers.

    A short textual introduction can be given with a descriptive headline, a descriptive title or possibly a descriptive label.

  • All sound clips and moving images must have a transcript. A transcript can also be a valuable addition to videos. A transcript is a written text describing everything that can be seen, heard and done. For example, all spoken text, but also the important images and sounds. Any interactive elements, such as a link, should also be included in a transcript.

    A good transcript:

    • contains all spoken text.
    • describes all important images.
    • describes all the important sounds.
    • contains all links.
    • describes who speaks when it is important.
    • emphasizes the speaker’s volume when it is important.

    A transcript should be easily accessible for all visitors. Always place a transcript, or a link to the transcript directly below the code of the media file.

    A transcript must always be added to sound clips. For the moving images, a transcript should only be added if no audio description is available. For videos, this is only required when there are interactive elements present in the video.

  • All videos must have subtitles for the deaf and the hard of hearing. In subtitles for the deaf and the hard of hearing, the spoken text and important sounds must be included. Important sounds are, for example, a doorbell or an explosion. Music can also be important to understand the video or the atmosphere of the video.

    Good subtitles:

    • contain all spoken text.
    • describe all the important sounds.
    • describe who is speaking if this is not immediately clear.
    • emphasize the speaker’s volume if it is important.
    • are clearly visible.
    • match the sound as much as possible.
    • do not cover any other information.

    The spoken text may be simplified to keep the subtitles from being too long.

    There are several ways to add subtitles: embedded in the video (open captions) or added as a separate subtitle file to the video (closed captions).

    How to add subtitles on the major video platforms:

  • Not all information available in videos is conveyed with sound. Some things can be seen but cannot be heard. This visual information must be added to the video with an audio description. In an audio description, a voice-over describes important visible images that cannot be deduced from what can be heard in the video. This can, for example, include actions, persons, but also text that can only be seen in the image. This takes place when there are pauses in the original sound of the video. This way visitors who are blind or visually impaired can also follow the video well.

    There are several ways to add an audio description: added in the sound of the movie or added as an alternative audio track.

    Note: An extra audio track is not (yet) supported by the major video platforms.

    An audio description should be synchronized as much as possible with the visible information.

    An audio description is not always necessary for videos. If all visible information can also be heard, then it is not mandatory. An audio description should only be added to moving images if no transcript is available.

  • Do not allow the sound to play automatically after a page loads, or at least make sure that the sound does not last for more than 3 seconds. It can be distracting for the visitors using reading software if the sound starts playing automatically. Then they can no longer properly hear the voice of the reading software. It can also distract visitors who have trouble concentrating.

    The sound that starts playing automatically should be easy to pause, stop, or be turned down. Make sure there is a pause or stop button and a volume control for the sound. A skip link can also be provided to make these controls easier to reach.

    The major video platforms make it possible to switch autoplay on and off. Change the settings to “off”.

  • Make sure that any moving, scrolling, or flashing content that starts automatically and lasts longer than 5 seconds can be paused, stopped, or turned off. This includes carousels, on-page animations, moving ads, etc. It may distract visitors with cognitive impairments. This can also be distracting for visitors who use a screen reader.

    These rules also apply to all auto-refreshing content, where it is also crucial that the frequency of the updates can be adjusted.

  • Do not use flashing content and do not allow for it to flash more than 3 times per second. Visitors with certain forms of epilepsy may experience a seizure when viewing flashing images or media.


  • Principle 1. Perceivable
    • Guideline 1.1 Text Alternatives
      • 1.1.1 Non-text Content
    • Guideline 1.2 Time-based Media
      • 1.2.1 Audio-only and Video-only (Prerecorded)
      • 1.2.2 Captions (Prerecorded)
      • 1.2.3 Audio Description or Media Alternative (Prerecorded)
      • 1.2.4 Captions (Live)
      • 1.2.5 Audio Description (Prerecorded)
    • Guideline 1.4 Distinguishable
      • 1.4.2 Audio Control
  • Principle 2. Operable
    • Guideline 2.2 Enough Time
      • 2.2.2 Pause, Stop, Hide
    • Guideline 2.3 Seizures and Physical Reactions
      • 2.3.1 Three Flashes or Below Threshold