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What is Closed Captioning?: Best Practices, Formats & Guidelines

Learn what is closed captioning, its importance, and how to implement it effectively. Enhance accessibility with best practices, formats, and guidelines.
Ortal Hadad
Content Specialist & Blog Editor
Last Updated:
March 4, 2024
Reviewed by
Ortal Hadad

Closed captioning is essential if you’re posting videos online. Not only do captions make your content more accessible, but they bolster your SEO performance and can increase engagement levels. Plus, generating captions has never been easier with ultra-accurate AI-powered tools like Riverside. The only problem is that when it comes to captions, you can get lost in all the jargon. It can be difficult to understand what you need to know from subtitles, open captions, transcriptions, and more. 

This article offers a clear and easy-to-use guide to closed captioning - from how to create them, what are the best formats, and more. 


  • Closed captions convey a video’s audio in written form
  • They’re different to open captions because closed captions exist in a ‘side-car’ file separate to the video file. 
  • Closed Captions help your video’s accessibility, SEO performance, and how engaging your content is
  • You can create captions effortlessly with Riverside’s highly-accurate AI-powered transcription generator compatible with over 100 languages.

What are closed captions?

Closed captions (CC) convey a video’s audio in written form. They reflect both dialogue and other sounds in the audio and are overlaid on the video, usually at the bottom of the screen. 

Crucially, the big difference between open and closed captions is that closed captions exist in a separate file from the actual video. This means that the viewer can toggle them on and off according to their preference. 

Origins of closed captioning

Captioning began with the idea of making video and audio content more accessible to those who are deaf or hard of hearing. The history of closed captioning goes all the way back to 1970. That year, the National Bureau of Standards and ABC started experimenting with encoding time information into television signals. Though that experiment didn’t go anywhere, the idea of sending captions came to life.

Two years later, “The Mod Squad” was broadcast with closed captions embedded. This was a major landmark but closed captioning still had a long way to go. In 1976, finally, the FCC reserved line 21 of the television signal for closed captions. And in the 1980s, the first pre-recorded programs with closed captions were broadcast (“The Wonderful World of Disney”, “The ABC Sunday Night Movie”, and “Masterpiece Theatre”) . 

Today when you turn on the TV, you always have the option to switch on closed captioning. Popular services like YouTube and Vimeo also include options to switch on CC. Sometimes creators add captions and sometimes video platforms add them automatically. 

Captions serve those who can’t hear but also cater to thousands of mobile viewers who browse the web without sound. 

How does closed captioning work?

As we mentioned, closed captions exist in what’s known as a ‘side-car’ file. This means they are not part of your video’s original file because it contains information incompatible with your video file’s format. They exist in a separate file you upload alongside your video and, if done correctly, should automatically sync up to your video’s audio. 

Why is closed captioning important for your online videos?

Now that you understand how closed captions work, let’s take a look at why they’re so important for your online content: 

Benefits of adding closed captioning to your videos


The increased accessibility of your content is the first and most obvious advantage of closed captions. Including closed captions ensures that viewers who are deaf, hard of hearing, or can’t have their audio on can still enjoy your videos. 


Closed captions also are a great way to maximize engagement with your content. According to a study by Verizon Media, 80% of consumers said they were more likely to watch a whole video if it had captions. 

Empower your viewers 

By going with closed captions, you’re giving your viewers the power to choose whether they want to use them or not. Let’s face it, not everyone wants to watch with captions all the time. 


Finally, uploading a caption file alongside your content is a great way to boost your SEO performance. Search engines can crawl your captions for key terms, which should help with your content's overall SEO ranking. 

Different Closed Captioning Formats

When it comes to captioning, there’s a lot of jargon to cut through. This section will break down the differences between closed captions, open captions, and subtitles. We’ll also take a brief look at major caption file formats. 

Closed Captions vs Subtitles and other Caption formats

Open captions vs Closed Captions 

Let’s take a look at the difference between open and closed captions. Unlike closed captions, open captions exist as part of a video file. The creator burns these captions into the video so they are permanently displayed. This means that viewers can’t turn them on and off. Like closed captions, open captions usually convey all audio detail in text form. 

Another difference between open and closed captions is customizability. With open captions, you have more power to customize the text's look, size and placement. 

Subtitles vs. Closed Captions 

Subtitles only convey dialogue. This differs from open and closed captions that translate all audio (dialogue, sound effects, music etc). You’ll typically see subtitles in foreign language content. Subtitles can be either closed or open, depending on the video type. 

Read more: Closed Captions vs Subtitles: The Difference & When to Use Each

Closed Caption File Formats

If you’ve explored closed captions before, you’ll know there is a whole range of file formats to choose from. The most common are: 

  • .SRT files (SubRip) are a plain text file format that contains your caption text in order, with start and end timecodes. 
  • .SBV or .SUB (SubViewer) are another type of plain text caption file format for adding captions or subtitles to YouTube videos. They include start and end timestamps for each caption. 
  • .VTT files (WebVTT) stands for Web Video Text Tracks. This file format is widely compatible. In addition to your caption information, .VTT files can also store metadata and other descriptions (such as caption placement).
  • .DXFP files (Distribution Format Exchange Profile) contain Timed Text Markup Language data (captions) in XML format. They work well for Adobe Flash videos. 
  • .SCC files (Scenarist Closed Captions) are a caption file format for broadcast tv and movies. They include your caption text, timings, and details about how your captions should look and where they should appear on the screen. 

Closed Captioning Guidelines: What Should Your Captions Include?

Closed captions usually reflect all audio. This means they convey dialogue, sound effects, music, and other background noise in text form. 

The FCC (the Federal Communications Commission) has several closed captioning rules that apply to television programs. These don’t apply to online content unless the video content first appeared on TV in the US. Either way, it’s good to try and bear these regulations in mind

  • Accuracy: captions must accurately convey the dialogue and background noises as much as possible.
  • Synchronous: captions should be in time with the relevant audio and appear on screen long enough to be legible to viewers. 
  • Complete: captions must run as much as possible from the beginning to the end of the program. 
  • Properly placed: captions shouldn’t block out important visual aspects or overlap each other. 

How to Make Your Own Closed Captions

There are a few ways to generate closed captions for your content: 

Closed Captioning Services

If you want to delegate captioning to someone else, you can use a dedicated closed captioning service that does your captioning for you. Depending on which service you choose, they might use human transcribers, AI, or a mix of both. 

Pricing will depend on the length of your audio, the desired turnaround time, and the type of transcription you want. 

Creating Closed Captions with an Online Generator

Alternatively, you can use an online generator or closed captioning software to produce your captions. Platforms like Riverside make it easy to generate ultra-accurate transcriptions fast - in over 100 languages. 

Riverside’s AI transcription tool automatically transcribes your recording once your session ends. You can then use your transcription to edit your video using Riverside’s text-based editor. Simply edit the text and see those changes happen in your video. You can also export your transcript in either .SRT or .TXT form.  

You can receive transcriptions straight after recording on Riverside’s Pro and Business plans, or you can use Riverside’s free transcription tool to generate your own transcripts.

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Best Practices for Creating Accurate Closed Captions

Recording high-quality audio 

The first step to generating accurate captions is recording high-quality audio to begin with. The quality of your audio links directly to the quality of your captions no matter the type of transcription you choose. 

If you choose an AI transcription generator, low-quality audio might negatively affect the output. This is because low-quality audio makes it harder for the AI tool to recognize and transcribe the dialogue accurately. 

 If you go with a human transcriber, bad audio may mean they’re unable to discern what’s said. That’s why using a high-quality recording tool like Riverside is so important to capture the best audio possible. 

Choosing the right service/generator 

Your choice of transcription tool or service will also impact the quality of your captions. Prioritize tools that generate high-accuracy transcriptions quickly. Slow turnarounds will delay your entire workflow, and you don’t want to spend hours fixing transcript errors. Luckily, tools like Riverside make it affordable and easy to generate ultra-accurate AI-powered transcriptions in minutes as part of your video production process.  

Checking over your captions 

Finally, always make sure to check and double-check your captions before publishing. You want to make sure that there are no mistakes. 

FAQs on Closed Captioning

What is the difference between closed captioning and subtitles?

Closed captions convey all your video’s audio in written form. Meanwhile, subtitles only reflect dialogue. 

What is an example of closed captioning?

When you’re watching a YouTube video, you’ll probably notice the ‘CC’ button on the bottom bar. This is an example of closed captions since you can toggle them on and off. 

How do I turn on closed captioning?

This depends on which platform you’re using. For example, YouTube and Vimeo both allow you to turn closed captions on and off on the bottom bar. 

Does closed caption mean no subtitles?

Closed captions and subtitles are related but not the same. As the viewer, you typically get a choice between closed captions and subtitles. For instance, if you’re native English speaker, you can switch on CC just to help your understanding of the audio. But if your first language is Spanish, you could switch on Spanish subtitles. 

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