WCAG 1.2.8 Media Alternative: Understanding the Requirements for Accessible Media

What WCAG 1.2.8 Media Alternative means

WCAG 1.2.8, titled “Media Alternative”, requires that prerecorded media have an alternative that gives the same information and function as the media. In plain terms, if content is delivered only by audio or by visuals, you must provide a text or audio equivalent so people who cannot see or hear can access the same information.

When this applies

• Prerecorded media such as lecture videos, training modules, marketing films and narrated slides.
• Media that conveys information visually only, such as illustrated slides without narration.
• Media that conveys information by sound only, such as spoken-word recordings with no visual component.

Options that satisfy the requirement

There are two common ways to meet the Media Alternative expectation. Choose the one that best preserves the original information.

• A full text alternative that contains all meaningful content from the media. This is most common for audio-only content or videos with little interactivity. The transcript must describe visual information as well as spoken words.
• Captions and audio description for videos where timing and visual detail matter. Captions provide the speech text and non-speech audio. Audio description supplies a spoken narration of important visual-only information.

How to decide which option to use

1. Identify what information is in the media that a sighted and hearing person would understand.
2. If the timing, pace or visual detail is essential (for example, a tutorial showing how to use software), prefer captions plus audio description.
3. If the media is primarily spoken content or a talk where visuals add limited value, a full transcript is usually enough.
4. If you can, provide both a transcript and captions/audio description. That covers more user needs and devices.

How to write an effective transcript

Not all transcripts are equal. A good transcript includes spoken words plus descriptions of visual-only content. Keep these points in mind.

• Label speakers. Use names or roles where relevant. Example: Interviewer: or Dr Smith:
• Describe important visual material. Example: [slide shows bar chart; labels and values described]
• Note timing when necessary. Use timestamps for long videos, for example [00:02:15], so users can jump to parts they need.
• Include non-speech audio. Describe sounds that carry meaning, for example [alarm sound] or [audience applause].
• Keep the format plain text or accessible HTML. Provide downloadable versions such as well-formed HTML or plain .txt for screen readers.

How to produce captions and audio description

Use caption files in standard formats such as WebVTT or SRT. For audio description, provide either an alternate version with description embedded or an extended description track.

• Captions must include speech and relevant non-speech sounds.
• Audio descriptions should narrate only when visuals add information not present in the main audio.
• Ensure synchronization so captions match speech timing and descriptions do not overlap with essential dialogue.

Testing checklist

• Turn the media sound off. Can someone using the transcript access the same information?
• Turn the screen off or cover it. Does the transcript and audio description convey visual-only content?
• Open captions in a media player. Do they include non-speech audio and match timing?
• Use a screen reader to read the transcript. Is the structure clear with headings and speaker labels?
• Check file formats. Are captions in WebVTT or SRT and transcripts in accessible HTML or plain text?

Common mistakes to avoid

• Providing only a short summary instead of a full transcript. Summaries lose essential detail.
• Transcripts that omit visual-only information such as text on screen or actions shown in the video.
• Captions that only include dialogue and skip important non-speech sounds.
• Posting captions that are out of sync or full of spelling errors.
• Hiding the transcript link where users cannot find it easily.

Practical step-by-step for compliance

1. Inventory all prerecorded media on your site. Note format, length and whether it includes essential visuals.
2. Decide per asset: transcript alone, captions plus audio description, or both.
3. Create the transcript. Include speaker labels, visual descriptions and timestamps where helpful.
4. Generate captions in WebVTT or SRT. Proofread and test for sync.
5. Create audio-described version if visuals add new information. Keep the description concise and timed into pauses where possible.
6. Publish with clear links. Place the transcript and caption toggle near the player and in the page text.
7. Run the testing checklist and fix issues. Repeat after any edit to the media.

Who benefits

• People with vision loss who need visual information described.
• People who are deaf or hard of hearing who depend on captions.
• People with cognitive or learning disabilities who use transcripts to review content at their own pace.
• People on low bandwidth connections who prefer text over streaming video.

Tools and resources

Use automated captioning as a first pass. Always proofread automated output. Use media players that support WebVTT and caption toggles. Offer transcripts in accessible HTML when possible.

Questions people often ask

Is a short summary enough?

No. A short summary can help search and orientation but does not replace a full transcript or captions if the media contains essential information.

Do live streams need the same alternative?

Live media has different technical constraints. Use live captions where possible and provide a post-event transcript or audio-described version when the recording is available.

Where should I put the transcript?

Place the transcript on the same page as the media. Provide a clear label and an easily clickable link so assistive technology and keyboard users can find it quickly.

Final checklist

• Transcript or captions available for every prerecorded media asset.
• Visual-only information described in the transcript or via audio description.
• Captions in a standard format and synchronised.
• Accessible placement and file formats for transcripts.
• Manual testing completed with sound off and with a screen reader.

If you need the exact legal or normative text of WCAG 1.2.8, consult the official W3C Web Content Accessibility Guidelines for the authoritative wording and conformance criteria.