Today, videos are everywhere, and for good reason. They’re highly popular with users, and a great way to boost engagement for people with diverse learning styles. By 2020, experts predict that 82% of consumer web traffic will be video. Because they convey information through both sight and sound, accessibility must always be a key concern when producing a video.
In order for your video to reach a full audience, you need to ensure the following:
- Ensure no flickering content
- Include only accessible content
- Use an accessible video player
- Disable autoplay
- Provide captions
- Provide video descriptions
- Provide a transcript
Ensure no flickering content
Videos with content that flashes more than three times in a one-second period can induce seizures in users with photosensitive seizure disorder, and can also trigger migraines.
Basic criteria:
- Do not display flashing images for a total duration of more than two seconds;
- Do not use stripes, whirls or concentric circles on large parts of the screen; and
- Avoid flashing the color red, which can be particularly problematic for some people
Tool Recommendation
To ensure there is no flickering in your video, download and run the Photo-sensitive Epilepsy Analysis Tool.
Include only accessible content
When creating the video content:
- Use only high contrast colors;
- Do not convey information using color alone; and
- Do not use patterned backgrounds.
To the best of your ability, also take care to produce the video in a way that will minimize the need for video descriptions (see the section below on providing video descriptions for more information).
Tool Recommendation
Test your video’s color contrast with Paciello Group’s Color Contrast Analyser.
Use an accessible video player
Keyboard navigation is essential for users who are unable to use the mouse. Without it, there is no way to exit the video player. The only option is to close the browser and start again. It’s also important that users on mobile devices be able to access your video.
Test whether your video player is keyboard and mobile accessible
Keyboard test
Using the keyboard only (no mouse), navigate to the video and determine if you can:
- Play, pause, rewind, fast-forward and move throughout the video;
- Modify the volume;
- Enter and exit full screen;
- Turn on captions; and
- Turn on video descriptions.
Mobile test
Using a mobile or tablet device, navigate to the video and determine if you can:
- Play, pause, rewind, fast-forward and move throughout the video;
- Modify the volume;
- Enter and exit full screen;
- Turn on captions; and
- Turn on video descriptions.
Disable autoplay
Many video players will automatically start when a page opens, which can lead to significant accessibility issues for many people:
- A screen reader user may experience the page’s text content being read over the playing video (and thus be unable to understand either);
- A user with a cognitive disability may become disoriented; and
- The mechanism to pause the video may be unavailable to users, or may not be keyboard-accessible.
To ensure accessibility, videos must always be presented without autoplay. This may involve “workarounds.” For example, YouTube does not allow you to restrict your videos from advancing automatically on their site, but you can embed individual videos on your own website without autoplay.
Provide captions
Captions are text versions of the sound and speech in the video. They are essential for people who are deaf or hard of hearing.
There are two types of captions: closed captions and open captions. Closed captions (represented on most video players as “CC”) can be turned on and off by the user. Open captions are printed on the video itself and cannot be turned off.
Video captions should:
- Appear at the same time as the sound they are captioning;
- Ensure all important audio information has been captured;
- Appear on the screen for enough time for them to be read;
- Ensure the contrast between background and caption text color is sufficient; and
- Attribute speech to a particular speaker.
Live events
For live events, such as an online webinar, you must hire a captioning service to provide Communication Access Realtime Translation (CART). CART provides instantaneous, verbatim translation of the spoken word into text to audience members.
During a live event, you must also describe the essential visual elements of a presentation so that this information also appears in the captions.
Following the event, the captioning service will provide a transcript of the event, which (once edited for accuracy) you can use to add captions to the archived video.
Automatic captioning
Some platforms (such as YouTube) now provide an automatic captioning feature when a video is uploaded.
This service can be useful for creating a first draft, and for accurately time stamping your captions. However, the error rate is extremely high, and automatic captions are never a viable alternative on their own. You must always budget time to edit and fix the drafted captions manually before publication.
How to create captions for your video in YouTube
- Using the previous transcript developed, delete all the visual descriptions.
- Save the transcript as a plain text file (“.txt”)
- Upload your video to YouTube.
- Go to the YouTube Video Manager and select the dropdown next to the “Edit” button on your video.
- Select the “Captions” option.
- Select the “Add subtitles or CC” button.
- A dropdown will appear. Select your language.
- Select “Upload a file.”
- Select your file type as “Transcript.”
- Select “Choose File” and select your transcript.
- Select “Upload”.
- Select “Set timings.” Allow the video and the transcript time to synchronize.
- Select “Publish.”
- Select your caption track.
- Select the “Actions” button. A dropdown appears.
- Save the captions track in your preferred format. (*.vtt, *.srt or *.sbv)
Provide video descriptions
Video descriptions (referred to as “Audio descriptions” in WCAG 2.0) provide an audio description of what is visually occurring on the video.
Video descriptions should:
- Adequately describe the visual information;
- Not impinge on other speech or important sounds;
- Be concise but sufficiently explanatory; and
- Be sufficiently distinguishable from other speech.
They can be included in a video in three ways:
As part of the video
The absolute best way to include video descriptions is to include them in the video content itself. If you plan out the video with accessibility in mind, this step is seamless and will eliminate the need for adding video descriptions later.
- Ensure that any text on screen is read at the same time. For example, introduce the speakers /affiliations in the audio track, rather than just printing them onscreen.
- When writing the audio narration script, include an explanation of any important visual information during scenes.
Standard video descriptions
Standard video descriptions are inserted into natural pauses in the audio track. A video with standard video descriptions is the same length as a video with these descriptions turned off. The video descriptions are a second audio track and can be turned on and off by the user.
Extended video descriptions
Extended video descriptions must be used in cases when the video descriptions are too long to be inserted into natural pauses. In these cases, the video itself must be paused while the descriptive tracks play. A video with extended video descriptions is typically much longer than a video with these descriptions turned off (and thus less convenient for users).
How to create video descriptions in Adobe Premiere
- Using the previous transcript developed, delete all the captions.
- Open Adobe Premiere and create a new project.
- Under “File”, select “Import” and select your video. The video appears in the lower-left pane.
- Double-click your video and it will be added to the source viewer at the top-left of the program.
- Drag the video into the Timeline section in the bottom-right pane.
- Using the Timeline, make note of where each video description should be added.
- Select the “Audio” button at the top.
- On the second Track Mixer select the “R” button to record.
- In the timeline, drag the cursor to where you first need to record a video description.
- Select the round red “Record” button. Press space to begin recording. Once you have recorded the video description press “Space” again. The new audio track will appear in green in the Timeline.
- Repeat steps 9 and 10 until all video descriptions have been recorded.
- Mute all audio and video tracks in the Timeline except for this newly created audio track.
- Under “File,” select “Export” and then “Media”.
- Select “MP3” as the format.
- Select Export.
Provide a text transcript
Text transcripts are essential for people who cannot see or hear the video player. In addition, many people without disabilities in your audience may also reply upon them, including people unable to use Adobe Flash software, people in a group/open work environment, and people with slow internet.
A text transcript provides a full alternative to playing the video. It includes the audio captions, as well as a text version of the video descriptions.
Video transcripts should:
- Identify the name of the speaker;
- Ensure that all speech content is included;
- Include relevant information about the speech;
- Include relevant non-speech audio;
- Include any textual or graphical information shown in the video;
- Be provided in an accessible format;
- Indicate the end of the transcript if on the same page as the video; and
- Provide a mechanism to return to the video if on another page.
For a one-minute video it takes approximately 30 minutes to write a complete transcript.
Best practices for text transcripts
Provide a full transcript, or a link to the transcript, immediately underneath each video. If the video transcript is on the same page as the video, the end of the transcript should be clearly marked in the text. If the video transcript is on a different page to the video, be sure to include a link back to the video.
Only people who can’t or don’t want to view the video will access the transcript, so it’s important that additional information, such as credits, are not included in the transcript unless they are also in the video.
How to create a transcript for your video
- Write a script of the video – including only people’s speech.
- Attribute all speech to a speaker.
- Where there is a change in speaker, indicate this in the transcript.
- Add relevant information about the speech in brackets prior to the speech (for example [shouting])
- Add in all other audio content that is relevant to the video in italics (for example, doorbell rings)
- Add into the transcript any text that is shown on the screen.
- Write a description of each scene, where it is relevant to the video.
- Alternately, it is common to hire a captioning/transcription service to create the transcript from a video or audio track.
Conclusion
For more information about video accessibility, please visit the W3C Web Content Accessibility Guidelines.
You can also explore additional resources on accessible technology training by visiting the article Knowledge is Power: Training Your Staff on Accessible Technology Issues.
This page's content was drawn from "Video" by AccessibilityOz, which was created with funding from the Australian Bureau of Meteorology. It is licensed under a Creative Commons Attribution Non-commercial license.