Closed Captions

The information presented within this glossary entry is aimed at website owners seeking to learn the ropes of web accessibility. Technical elements are described in layman’s terms, and, as a rule, all topics pertaining to the legalities of web accessibility are presented in as simplified a manner as possible. This guide has no legal bearing, and cannot be relied on in the case of litigation.

Closed captions are a textual representation of the audio within a video, specifically designed to enhance accessibility. This feature is crucial for making video content accessible to individuals who are deaf or hard of hearing, and to enhance comprehension for abled viewers, as well. Closed captions go beyond just transcribing spoken words; they also include important non-verbal auditory information such as background noises and auditory cues, which play a significant role in understanding and enjoying the content.

Ensuring web accessibility through closed captions is not just a matter of convenience but also a compliance requirement. Providing captions for meaningful video content is required under the Web Content Accessibility Guidelines (WCAG), which are the standard for compliance under certain web accessibility laws. By including closed captions in video content, content creators and website owners contribute significantly to building an inclusive digital environment that accommodates the needs of all users.

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Technical aspects of closed captions

Closed captions are not just a simple text overlay; they come with various technical aspects that enhance their functionality and accessibility.

Closed captions formats

Closed captions are available in multiple formats, each suitable for different use cases. For web content, popular formats include SRT (SubRip Text) and WebVTT (Web Video Text Tracks). SRT is widely used due to its simplicity and compatibility with numerous video players. WebVTT offers more advanced features, like positioning and styling, which are beneficial for web-based video players.

Language options

Closed captions often come with multiple language options. This feature is particularly useful in a globalized world, as it ensures that content is accessible not only to those who are deaf or hard of hearing but also to non-native speakers. The availability of captions in various languages can significantly broaden the audience reach of video content.

Open vs. closed captions

The two significant types of captions are open and closed captions. While both serve the essential function of transcribing audio content for accessibility, they differ in how they are presented to the viewer.

Open captions are a fixed part of the video, always visible and not requiring any action from the viewer. Closed captions, in contrast, offer viewer control, allowing them to be toggled on or off according to individual needs or preferences. This distinction makes each type suitable for different viewing contexts and user requirements.

The difference between subtitles and closed captions

While often used interchangeably, subtitles and closed captions serve different purposes:

Subtitles are designed primarily for viewers who do not understand the language of the audio, providing a translation of the dialogue.

Closed captions, on the other hand, are intended for viewers who are deaf or hard of hearing, and include not only dialogue but also non-dialogue audio cues like background noises and sound effects. This makes closed captions a more comprehensive tool for accessibility.

Closed captions and web accessibility

Integrating closed captions aligns with the principles outlined in the Web Content Accessibility Guidelines (WCAG). Developed by the World Wide Web Consortium (W3C), WCAG provides a comprehensive framework for making web content more accessible to a broad range of people with disabilities. 

Adherence to WCAG standards is not only a best practice for web accessibility but also a legal compliance measure in various jurisdictions. WCAG is the benchmark for compliance with several accessibility laws, such as Section 508 in the United States and the Accessibility for Ontarians with Disabilities Act (AODA) in Canada. Furthermore, U.S. courts and the Department of Justice frequently reference WCAG as the standard that websites should meet to comply with the Americans with Disabilities Act (ADA)

Closed captions requirements under WCAG

WCAG sets specific success criteria for closed captions, ensuring that video content is accessible to individuals with disabilities. It's important to note that WCAG distinguishes between meaningful and non-meaningful video content

Meaningful video content is a term that applies to videos that convey essential information or are integral to understanding the web page's message. WCAG requires closed captions for such content to ensure accessibility. Conversely, non-meaningful video content serves decorative or ambient purposes. Closed captions should not be these types of videos. 

To conform to WCAG and provide accessible closed captions for meaningful video content, the following measures must be applied:

  • Captions should be ‌full and accurate: Closed captions must provide a full and accurate representation of spoken words, dialogue, and important non-verbal audio cues such as background noises and sound effects. Accuracy is vital to ensuring that viewers receive complete and correct information. To that end, those relying on automatically-generated closed captions (such as those offered on YouTube) must review they are accurate and fully-convey the content conveyed throughout the video
  • Color contrasts: There should be sufficient contrast between the text of the closed captions and the background to ensure that the captions are easily distinguishable
  • Closed captions must meet specific text size requirements to ensure readability: The minimum text size varies based on accessibility guidelines, but it should be large enough to be legible even on smaller screens
  • The ability to turn captions on and off: Closed captions should be designed to allow viewers to toggle them on or off according to their preference

Closed captions' impact and importance beyond web accessibility

Closed captions offer significant benefits that extend beyond their primary role in web accessibility. They play a crucial role in enhancing the overall user experience and content discoverability.

Closed captions’ SEO benefits

Closed captions significantly contribute to the SEO of video content. By providing text-based representations of the audio, closed captions make the content more indexable and searchable by search engines. This is particularly important because search engines typically have a harder time crawling and understanding video and audio content compared to text. Captions, therefore, offer an additional layer of context and information that can be indexed by search engines, improving the visibility and searchability of ‌video content.

Moreover, incorporating closed captions into videos can lead to improved organic reach. When a video is accompanied by accurate and comprehensive captions, it becomes more accessible not only to individuals with hearing impairments but also to a broader audience, including those in sound-sensitive environments or non-native speakers. This increased accessibility can translate into higher viewer engagement and longer watch times, which are positive signals to search engines and can improve the video's ranking in search results.

Closed captions fit with modern viewing trends

In the current digital media landscape, closed captions have become increasingly vital, aligning with contemporary viewing habits, especially in mobile environments. 75% of those who watch videos on their mobile prefer to do so with the audio turned off. This change in viewer preferences reflects the diverse settings in which audiences consume video content, ranging from public spaces to personal preferences for a quieter viewing experience.

Furthermore, and in large part due to prominence of social media as the medium through which video content is consumed, 50% of Gen Z and millenial viewers watch TV with captions turned on. Ensuring closed captions are available and accurately convey what is transpiring on screen is therefore important for all viewers, including those who are sighted.

The universal application of closed captions across media platforms

Closed captions are essential across various platforms, enhancing accessibility and viewer engagement:

  • Television and movies: Required in the U.S., captions include dialogue, background noises, and sound effects. Guidelines by organizations like the DCMP, FCC, along with WCAG ensure captions are accurate, clear, and readable​​
  • Streaming services: Netflix and Amazon Prime, among others, are legally required to provide captions, under the ADA. Netflix focuses on localization and readability, ensuring captions in all streaming content​​
  • Social Media and online platforms: YouTube offers captioning tools for content creators, recognizing the value in reaching a wider audience. Zoom also supports closed captions for its meetings, acknowledging the need for accessibility in various communication forms​​
  • Live streaming services: Platforms like YouTube Live and Facebook Live use services like CART to provide real-time captioning, making live events more inclusive​​

The role of captioning services in content accessibility

Captioning services are utilized to transcribe and present the audio content of media in a written format. Their core function includes:

  • Transcription: The audio part of a video or broadcast is transcribed into text. This includes spoken dialogue, sound effects, and other relevant auditory information
  • Timing and synchronization: A crucial aspect of these services is to ensure that the captions are perfectly timed with the audio. This synchronization is essential for the viewers to follow along with the content effectively

The primary goal of captioning services is to enhance the accessibility of content, making it available to a wider audience, including those with hearing impairments or those in environments where audio cannot be played. They employ various technologies and skilled professionals to achieve a balance between accuracy and readability.

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