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Creating Accessible Video


Of the two methods for creating accessible videos, captioning and describing,  captioning is more supported as evidenced by the number of tools available for producing and editing captions. On this page, you'll get started with captioning by exploring a number of workflows for creating your own captioned videos with free tools. Additional resources are provided for you to continue learning about captioning and audio description as your understanding of accessibility grows.   

Getting Started with Captioning

Depending on your familiarity with accessible video and your skill level, we have provided three possible workflows you can follow to end up with a captioned video. We'll start with the simplest one, editing the automatic captions generated by YouTube when you upload a video, and proceed to the more advanced one, where you would use the free CADET tool to caption a video on your computer.  

Edit the Automatic Captions on YouTube

Video Description

Inclusion of verbal or auditory descriptions of on-screen visuals intended to describe important details not contained from main audio output.

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Access for all people, including people with disabilities, to web environments.

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While automatically generated captions are of low quality, they can be transformed into high quality captions with some editing for accuracy and proper timing. Once your video has finished processing, you can edit YouTube's automatically generated captions by correcting errors and adjusting the timing of the individual caption clips. 


Upload a Transcript to YouTube

Another option is to create a transcript and let YouTube add the time codes to make sure the video and the captions are in sync. The transcript can be created in one of two ways:

  • Using a tool such as Express Scribe to create a transcript file, then importing that file into YouTube to add the timings needed for captions.  
  • Using YouTube’s Transcribe and Auto-sync feature. You will type the captions in a provided text field and then select “Set timings” when you are done to have YouTube convert the transcript text into properly timed captions. To make the process easier, YouTube can pause the video each time you start typing your transcript text.  

With either method, accuracy will depend on the quality of the audio. For the best results the video should also be less than one hour long. 

Eric Moore, a UDL and accessibility specialist at the University of Tennessee in Knoxville,  has shared a shortcut for using YouTube's Transcribe and Auto-sync feature to create captions in his Ninja Way to Speed Up Accurate Captions on YouTube video. You will start with YouTube's automatically-generated transcript, download it into a Microsoft Word document, perform any edits that are needed and finally copy and paste the transcript text into the Transcribe and Auto-sync text field on YouTube to set the proper timing. 

Manually Caption a Video with CADET


Digital form or representation of a sound which may be used for non-visual access to text and images.

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Universal Design for Learning (UDL)

Framework of learning and teaching, resisting one-size-fits-all approach. Encourages offering multiple means of representation, expression, and engagement.

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The Captioning and Description Editing Tool (CADET) is a free captioning tool from the National Center on Accessible Media (NCAM) at WGBH. CADET supports the following features for captioning:

  • It is available for Mac and Windows in both 32-bit and 64-bit versions (make sure to download the correct version for your operating system).
  • It runs as a web app that works on most browsers.
  • It has a built-in editor where the audio from a video can be transcribed and timed using a number of easy-to-learn keyboard shortcuts.
  • It supports styling and placement for captions.
  • It supports the importing of plain text transcripts or caption files in order to perform error correction (supported formats for import include WebVTT and SRT - the latter format is used on YouTube and many other video hosting services).
  • It has support for exporting to popular caption file formats, including WebVTT, SRT, SCC and more.

CADET supports the following keyboard shortcuts:

  • Control and Space to starts/stop playback and allow you to listen to the video
  • Control and Comma to add a caption timecode
  • Control and Period to add an end time at the previous caption (this indicates a pause in the video where no audio is present)
  • Enter/Return twice to create a new caption row

Captioning Support in Video Editing Applications

The following video editing applications include captioning support in their content creation workflows (follow the links for specific instructions for working with captions in each application):

Apple’s Clips iOS app uses speech recognition to add Live Titles (open captions) to any video clip. It is possible to edit the captions when the speech recognition is confused by poor audio. 

Microsoft’s Flipgrid also allows educators to turn on automatic captioning on a Grid (the equivalent of a YouTube channel). These captions can be edited for accuracy.   

Commercial Captioning Tools

MovieCaptioner (Mac/Windows) is a commercial application for creating and editing captions. MovieCaptioner works by repeating a 4-5 second snippet of the video to ensure it is captioned accurately.

Telestream’s CaptionMaker (Windows) and MacCaption (Mac) are professional-level tools for creating captioned and subtitled videos. They have a steeper learning curve compared to the other tools shared on this page.

Most services, including YouTube, allow you to upload a caption file created with another tool. Instructions for uploading captions files are listed for the various video hosting services, along with their supported formats:

Audio Description Tools

YouDescribe is a free tool for adding audio description to existing YouTube videos. All that is needed to use YouDescribe is a microphone and a connection to the internet. Descriptions are added through a web interface (YouDescribe runs best in Google Chrome). They can be inline or extended. Inline descriptions are added into pauses in the video to make sure they don’t get in the way of the existing dialogue or narration. Sometimes there is not enough time in a pause to add a description that effectively explains what is happening in the video. In that case, an extended description can pause the video while the description plays back. The video will then resume after the extended description has been heard in its entirety.

YouDescribe is also a community for sharing and rating described videos. In addition to the YouDescribe website, an iOS YouDescribe app is available. Currently, the app only allows browsing and rating the videos on the YouDescribe site.

CADET has a description feature, but it is only meant to identify the pauses in a video where descriptions will fit, and then provide description text to fit within those pauses. The result is a transcript with timing cues a human narrator can use to record a voice-over track. With a new  presentation mode in CADET, the descriptions in a CADET description project can be read aloud with text to speech during video playback. 

The Screenflow screen recording app has an option for using text to speech to add audio descriptions. To add a new description, choose Insert, Speech Clip and type the text to be converted into audio using one of the built-in text to speech voices.

Captioning and Description Services

Even with the best tools, captioning is still a time-consuming and often laborious process. If you have hours of video to caption, you many want to consider hiring a captioning service. These companies offer a range of captioning services, from transcription to translation into other languages and subtitling:

Some of these companies offer audio description services as well.

Text-to-Speech (TTS)

Artificial production of human speech, using special software and/or hardware.

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