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The Science of Subtitles: Learn Everything About How Subtitles Actually Work


Sep 11, 2019

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RevBlogSubtitlesThe Science of Subtitles: Learn Everything About How Subtitles Actually Work

Here at Rev, we’re firm believers that all video content deserves to be subtitled.

Subtitles make videos more accessible to a wider audience, including foreign-language speakers, hard-of-hearing individuals, and anyone who can’t watch a video with sound. They also help improve engagement and boost SEO for content producers.

Even though subtitles are common and familiar, not a lot of people understand what goes into creating high-quality subtitles for a video. But if you create video content and want to keep your subtitles from being ineffective, it’s good to understand both the art and the science behind them and how to make the best subtitles.

Why It’s Important to Know How Subtitles Work

What is a subtitle, anyway? Although many people use subtitles and captions interchangeably, there actually is a difference between the two. Knowing the difference between captions and subtitles helps you choose the best one for you, giving you a head start in creating them.

Knowing the difference between captions and subtitles helps you choose the best one for you, giving you a head start in creating them.


Captions are designed to increase video accessibility for individuals who are deaf or hard of hearing. Captions are a transcription, usually word-for-word, of the video’s spoken dialogue, and may not exactly match the pacing of the dialogue or action. They may also include background noises, speaker differentiation, and other important audio information that helps a person understand the video without sound.

Captions usually appear as white text on a black bar, normally at the bottom of the screen. Videos may have open captions, which are permanently embedded into the video, but it is more common to have closed captions, which can be turned on and off.


Subtitles are a translated version of a video’s transcription, meant to give the viewer a real-time experience of what is happening on screen. These subtitles usually appear as text on the bottom of the screen. Typically subtitles are intended for use by viewers who do not speak the language used in the video, but who can still hear other sounds, like music, and can tell which person is speaking.

Subtitles for the Deaf or Hard-of-Hearing (SDH), however, also include important non-dialogue information, such as speaker identification or sound effects. If a viewer cannot hear the video, the additional information in these subtitles can aid in comprehension.

Subtitles Add Value to Video

No matter where your audience is located, subtitles are a valuable addition to your video content. One in five Americans speaks English as a second language (ESL), of which 41% think they speak English “less than very well.” That equates to more than 25 million ESL viewers who may need a little help understanding every word spoken in an English-language video. Plus, subtitles can help them increase their English-language proficiency by helping them understand slang, regional accents, and other nuances of language.

No matter where your audience is located, subtitles are a valuable addition to your video content.

Subtitles are also used by native English speakers for a variety of reasons. For example, online video subtitles can improve video accessibility for individuals with ADHD, autism, and dyslexia. Some people are more visual learners, and prefer to watch videos with subtitles to help them better retain the information.

Adding subtitles to your videos allows viewers to enjoy your content, even without sound, or in situations with loud noise that may interfere with the video’s audio. Making subtitles a part of your video’s post-production can help you appeal to a wider audience, grow engagement, increase accessibility, and even improve your video’s search rankings. Videos with subtitles have longer viewing times, which increases your watch time and video shares.

Videos with subtitles have longer viewing times, which increases your watch time and video shares.

Understanding the value of video subtitles can help you get in the right frame of mind for creating the best subtitles for your content.

Creating Subtitles That Work for Different Types of Audiences and Content

Both captions and subtitles provide valuable information that adds to the viewer’s experience. To provide the optimum experience when viewing your video content, any subtitles you include need to have a certain level of quality to them. Subtitles should be created in a way that provides all the necessary information, without being distracting or inaccurate.

For example, a quality subtitler should know the optimum pace for the subtitles, and will be able to tweak video subtitles to match the pace and tone of the video. They will be able to choose the right video frames to start and end the subtitles on. Imagine the potentially disastrous results if a subtitle creator doesn’t pay attention to details like that! A poorly paced subtitle can ruin the impact of your video, such as appearing too soon and giving away the ending of a dramatic scene.

A poorly paced subtitle can ruin the impact of your video, such as appearing too soon and giving away the ending of a dramatic scene.

The right subtitler also can account for the number of speakers on screen. They may change their subtitle style and pacing based on whether the video’s scene is fast or slow, or whether there is only one or two speakers in the video compared to a panel of a dozen speakers. Slower scenes or fewer talkers will change the timing of subtitles, and allow them to appear on a screen longer. Fast-paced videos or numerous speakers create more words that may compete for screen space. Experienced subtitlers will have the necessary skills to keep all these factors in mind and pace the subtitles for optimal comprehension.

Here are some of the many different things that high-quality video subtitles, created by experienced professionals, have to take into account:

  • There are about 24 frames to every second of video; a person experienced with creating subtitles will know which frames are the best ones for each subtitle to appear on.
  • Subtitle timing not only determines when the text appears but also when it disappears; it needs to be paced for readability, while also keeping up with the action.
  • Sometimes subtitles need to be shortened, but still convey the exact same meaning as the words that are spoken. The substitute word should be carefully chosen so that no meaning is lost in translation.
  • Subtitles should generally adhere to a rule of 12-15 characters per second of video

Besides the timing, the text and formatting of a subtitle is important, too. Details include:

  • Legible, sans-serif font with a consistent width and thick outlines
  • A font that supports the use of symbols, such as music notes, that offer additional information
  • Matching the style to the spoken word (such as the use of slang or industry jargon), even if the subtitles have to be abridged
  • Appearing in about two lines of about 35 characters

Subtitles Work Differently For Different Viewers

When creating video subtitles, it’s important to keep more than just the content in mind—you also need to consider the audience. Subtitles may need to be altered slightly to meet the needs of different audiences. For example, video subtitles targeted at children will be different from video subtitles targeted toward adults. Also, the subtitles for a general audience may be different from those intended for specialists.

When you create subtitles for your video content, it’s a good idea to plan ahead. This means that, before you start the actual process of creating subtitles, you’ll have to know exactly what your video is meant for, and who its target audience is. The better a subtitler understands the video itself and the strategy behind it, the more accurate and clear the finished subtitles will be.

How to Add Subtitles to a Video

There are many different ways you can create subtitles for your videos, from overseas translation services to DIY methods to automatic subtitling apps and services. However, the quality of these services can vary widely. To ensure your audience fully understands the nuances of audio, it’s important to choose the option that will give you the best subtitles.

There are a few key things to consider:

  • How much time do you have for one video? Do you need to subtitle multiple videos?
  • What is your budget? Can you afford to hire a company to subtitle your video?
  • How accurate is your chosen method? Will you have to review the files more than once?
  • Which method will you use if you choose the DIY method?

Trying to answer all these questions would drive anyone a little crazy.

Alternatively, you could work with a company who specializes in transcripts and can easily create subtitles for your online videos. With a subtitle service like Rev, you can relax with the knowledge that your video subtitles will come from a trusted company with a record for high accuracy. This will let you focus on other essential tasks.

Rev’s caption service offers transparent pricing with a flat rate, fast turnaround time, numerous foreign language options, and accurate results that will make your video content entertaining and effective for your target audience. Even better, it’s incredibly easy to get started:

Use our online ordering, with several helpful options:

  • Upload files from your computer to our ordering page
  • Share a link to your video if it is publicly viewable
  • Pull videos directly from your YouTube or Vimeo account
  • Choose the options you need for your subtitles
  • You can also provide a transcript or vocabulary list, if you have one, in the order form, under the Order Details section

Payment is available by credit/debit or PayPal. Our online order form will charge your card or account at the time of ordering. If you want, you can securely save your credit card info to your account for future orders. If you have large, recurring needs, you may be eligible for monthly billing.

Our team of more than 1,000 professionals will go to work on your file, using our innovative platform that includes tools built in-house. Members of our subtitling team are native speakers with years of experience.

We will email the finished file to you quickly (usually less than 24 hrs for most files under 20 minutes). You will then be able to use our interactive tools to review, edit, and annotate subtitles alongside the video, then share and export in your preferred format.

We guarantee at least 99% accuracy for files with good audio. Our captions are both FCC and ADA compliant. Find any discrepancies? We will work closely with you to correct them. If there is ever an issue, we encourage you to contact our team to answer your questions or address any concerns you may have.

Good subtitles may seem tricky, but it’s easy to see their value! Make things easier on yourself and your team by trusting the experts at Rev to account for all the nuances involved in quality subtitles. Get started today and see the difference that experience provides!

Affordable, fast transcription. 100% Guaranteed.