Video captioning

Meeting accessibility standards is an objective in Cornell’s strategic plan. For videos, this entails captioning, which is the responsibility of the owner of the video content.

The universal solution is to work with a professional service to transcribe and caption your videos–they work from your video to produce the caption file. If you do it yourself, the biggest effort is in obtaining a transcription. If you’re working from a script, you’re largely there, but if not, automated speech to text is available from various sources. Most of the time this is not accurate enough for good results, but editing is often much quicker than transcribing the material yourself.

A captioned video contains text that transcribes the narration and provides descriptions of the sounds and music that are present. The assumption is often that this is for use by people with hearing difficulties, but captions also benefit people who aren’t native speakers of the language used in the video, for those unfamiliar with the vocabulary of a discipline, and sometimes to allow interactive searches within the video. There are two ways to caption a video: open captions and closed captions.

Open captions

Open captions burn the text onto the video image. If you can view the video, you will see the captions. They can’t be toggled on/off, and no player functionality is required. Open captions are added with a video editing process.

Closed captions

Closed captions are the opposite. They can be toggled on/off, and require player functionality in order to be viewed. Closed captions are done using a timed-text file which is created by adding time codes to a transcript of the video. This is the approach most likely to be used if you need to caption your videos.


Cornell services

Student Disability Services provides captioning services for qualified students with disabilities (primarily Deaf/Hard of Hearing). If using video content in a course in which a Deaf/Hard of Hearing student is enrolled, please contact the SDS office at if assistance is needed with captioning video content.

Academic Technologies has contracted with a vendor that provides captioning services for closed-captions.  If you are interested in using this service, feel free to use our easy access form.  If you have general questions about captioning, contact us at:  607-255-9760.


Creating a caption file

The first step for either of the above options is to get an exact transcription of the video. This is time consuming and error-prone for people who aren’t transcriptionists. In addition to accurately capturing the dialog (which for impromptu speech is often disjointed), the transcription should identify who is speaking when there are multiple voices, and describe sounds. From our experience it is best done by editing a file created with speech recognition or by paying for a professional transcription. The transcription process is often combined with the process of creating the caption file, which includes timing information. If captioning is needed to meet the needs of your students, Student Disability Services at Cornell will have additional options.

If you will be creating an open captioned video, the transcribed text is added to the video using features of the video editing software you are using. Some programs, like Adobe Premiere, will use automated speech recognition to capture and place the text.

For closed-captioned videos, timing information may need to be added (if it wasn’t done in the transcription process) to create the caption file.

There are several formats for timed-text files. The Kaltura system used in Blackboard requires .SRT or DFXP files. If you are hosting your own video on a web site, the different video formats can require other formats. All Academic Technologies video-related services (Kaltura in Blackboard, and Panopto) support caption files. Upon request, it is also possible to use a section 508 compliant video player to playback videos in your course or on your web site.



For immediate support:

607 255 9760 (M-F, 9a - 5p ET)

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