Adding Captions to Videos

There are a number of options for automatically captioning videos (see our Screencast-o-Matic and YouTube guides for a few of these options), but there may be occasions when you need to manually embed captions into a video file. The guide below outlines one method to accomplish this.

Note that if you are planning to embed captions, you should leave a space at the bottom of your video that is clear of text, titles, and other important information (since this space will be covered by your caption text).

Review a Captioning Style Guide #

To ensure your captions are useful for viewers, it is a good idea to review the recommended standards for words-per-minute, caption duration, word matching, and other issues. There are many places online to find this information, but this guide from the University of Melbourne gives a good, quick overview of best practices in captioning style.

Create an SRT File #

An SRT file is just a text file that has been formatted with timings that video encoders can read when creating captions. They look like this:

While you can create an SRT file manually by simply typing the timings and text as shown above, you can save a lot of time by letting an automated system take a first pass. We recommend YouTube as a free way to generate autocaptions.

Using YouTube to Autocaption #

If you don’t have a YouTube account, or need help uploading videos to YouTube, you can follow our YouTube Basics guide to get started.

Note: If you are uploading a video exclusively for captioning purposes and don’t want it available for viewing on YouTube, make sure to set your video as Private when uploading.

Once you have a video uploaded to YouTube, the algorithm will automatically start generating captions. It can take up to a day for captions to appear.

Once the captions are generated, you can use YouTube Studio to download them. Follow these steps:

  1. Log into your YouTube Studio account, and click the video you want to caption.
  2. Click the Subtitles tab on the left side of the screen.
  3. You should see a subtitle option listed as “English (Automatic).” Click Duplicate and Edit next to this option.
    Note: If you don’t see the “English (Automatic)” subtitle option, the autocaptions may not have finished generating. Come back later and check again.
  4. You will now see a transcription of the speech in your video. There will be many errors, so you should spend some time now cleaning up the text.
  5. Once your captions are cleaned up, click Assign Timings.
  6. Click the three dots next to the “Edit as Text” button, and then click Download subtitles. This will give you an .sbv file, which will need to be converted to .srt.

Converting SBV Files to SRT #

SBV files are similar to SRT files, but different enough to cause trouble for most video encoders. Luckily, there are many automatic converters for SBV files. We recommend this in-browser converter from the Described and Captioned Media Program (dcmp.org). Follow these steps to convert your file:

  1. Open your .sbv file in any text editing program (Microsoft Notepad, Apple TextEdit, etc.).
  2. Select all the text in the file, and copy it.
  3. Go to the converter page in your internet browser, and paste the text into the field.
  4. Click Convert. The text you entered in the field will convert to SRT formatting.
  5. Select all text in the field above the Convert button, and copy it.
  6. Delete the text in your old .sbv file, and paste the new text into it.
  7. Use Save As to save the file with a new name, and add the file extension “.srt” to the end (e.g. “captions.srt”).

Use Handbrake to Embed Captions #

Handbrake is a free and open source video encoding tool. You can download it for any operating system from the Handbrake website.

Follow these steps to embed captions into a video using Handbrake:

  1. Open Handbrake, and select (or drag and drop) your video file.
  2. Click the Subtitles tab.
  3. Click Import Subtitle, and select your SRT caption file.
  4. If you want Open captions (captions that are visible all the time and cannot be turned off), check the box next to Burn In. If you prefer Closed captions (captions that are only visible when turned on by the viewer), leave this box unchecked.
  5. Click the Start Encode button. Handbrake will take a few minutes to encode your file (longer for long videos).
  6. Once encoding is complete, open your video file and review the captions to make sure all went as planned.