Video Missing Closed Captions Fix

In this tutorial, you'll learn about Video Missing Closed Captions Fix. We cover key concepts, practical examples, and best practices to help you understand and apply this topic effectively.

The Problem

Videos without closed captions are inaccessible to deaf and hard-of-hearing users. Captions also benefit users in noisy environments, non-native speakers, and anyone who wants to search or reference video content. Missing captions fail WCAG 1.2.2 (Captions - Prerecorded).

Quick Fix

Step 1: Add track element to video

<!-- Wrong — video without captions -->
<video controls width="640">
    <source src="tutorial.mp4" type="video/mp4">
</video>

<!-- Right — add track element with captions -->
<video controls width="640">
    <source src="tutorial.mp4" type="video/mp4">
    <track
        kind="captions"
        src="captions.vtt"
        srclang="en"
        label="English"
        default
    >
</video>

Step 2: Use valid WebVTT format

WEBVTT

00:00:01.000 --> 00:00:04.000
Welcome to this DodaTech tutorial on
JavaScript error handling.

00:00:05.000 --> 00:00:09.000
In this video, we'll cover the
most common JavaScript errors.

00:00:10.000 --> 00:00:14.000
First, let's talk about TypeError
and how to fix it.

Step 3: Add caption styling and positioning

WEBVTT

Style
::cue {
    background-color: rgba(0, 0, 0, 0.8);
    color: white;
    font-size: 1.2em;
    font-family: sans-serif;
    text-shadow: 1px 1px 2px black;
}

::cue(.highlight) {
    background-color: rgba(99, 102, 241, 0.9);
    color: white;
}

00:00:01.000 --> 00:00:04.000
<c.highlight>Important:</c> Always use
try/catch blocks for async code.

00:00:05.000 --> 00:00:09.000
This prevents unhandled promise rejections.

Step 4: Add multiple language tracks

<video controls width="640">
    <source src="tutorial.mp4" type="video/mp4">

    <track
        kind="captions"
        src="captions-en.vtt"
        srclang="en"
        label="English"
        default
    >

    <track
        kind="captions"
        src="captions-es.vtt"
        srclang="es"
        label="Spanish"
    >

    <track
        kind="captions"
        src="captions-fr.vtt"
        srclang="fr"
        label="French"
   >
</video>

Step 5: Provide alternative for third-party embeds

<!-- Wrong — embedded video without captions -->
<iframe src="https://www.youtube.com/embed/abc123"></iframe>

<!-- Right — use YouTube captions (enable in video settings) -->
<iframe
    src="https://www.youtube.com/embed/abc123"
    title="JavaScript Error Handling Tutorial"
    allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope"
></iframe>
<!-- Also provide a transcript below the video -->
<div class="transcript">
    <h3>Video Transcript</h3>
    <p>Welcome to this DodaTech tutorial...</p>
</div>

Prevention

• Always include a <track kind="captions"> element in every <video>
• Create captions in WebVTT format with proper timing
• Provide a text transcript as a fallback below the video
• Test captions by viewing the video with sound off
• Include captions in the same language as the audio, plus additional language tracks

Common Mistakes with video captions

1. Using foldl instead of foldl' causing stack overflow on large lists
2. Forgetting deriving (Show, Eq) on custom data types needed for debugging
3. Placing the wildcard pattern first in case expressions, making all subsequent patterns unreachable

These mistakes appear frequently in real-world A11Y code. DodaTech's contributors have identified these patterns through analysis of open-source projects and production systems.

Practice Exercise

Write a pure function that safely divides two integers using Maybe, then test it with edge cases like division by zero and negative numbers.

This exercise reinforces the concepts covered in this guide. Try implementing it before checking online solutions.

FAQ