Synthetic teaching example for a website delivery brief. Not a client result, live account test or certification.
A subtitle file is not the whole accessibility deliverable
When buying a website with training media, request the video and its accompanying information as a single delivery set. A captions file may describe sound while omitting an important action visible only on screen. Conversely, a visual transcript does not replace synchronised captions for a listener who cannot hear the audio.
In this original four-second example a steady tone plays throughout. A white square is at the left for the first two seconds and at the right for the final two. There is no speech, real software training or client footage. The visible change is the information a sound-only caption would miss.
| File | Filled content | Check |
|---|---|---|
| MP4 | Four seconds, square changes sides at 2s | Play both halves |
| English WebVTT | [Steady tone], 0–4s | Check track timing and selection |
| Descriptive transcript | Square moves left to right at 2s | Compare text with actual frames |
Download the video, English captions and bilingual descriptive transcript.
Use the filled example
Download the finite Node checker and filled input. Run with Node 24 or newer; no account, API or network is used.
node checks.mjs training-video-accessibility training-video-accessibility.jsonThe finite checker verifies supplied cue bounds and reports the scripted visual change. It cannot judge caption quality, sound perception or whether the media player exposes the track correctly. Human playback and a content-purpose review remain necessary. The transcript describes the visible movement as well as the sound, rather than claiming there is dialogue.
For a real instructional video, ask the supplier which actions must be understood without seeing the picture, how captions are corrected, and who owns later transcript updates. Agree the applicable accessibility requirements separately. This tiny audiovisual fixture is neither a full training module nor proof of compliance; no existing video or player is modified.
Primary facts and limits
W3C accessible audio/video planning: Planning distinguishes captions, transcripts and description of visual information.
Sources reviewed 15 October 2026. The supplied input and acceptance rules are original teaching design; check current platform versions and your actual delivery contract before implementation.