Closed Captioning

TelVue Connect has an optional feature that leverages IBM Watson’s speech-to-text algorithms to automatically generate timed Closed Caption files for videos: WebVTT for CloudCast VOD and OTT streaming, and 608/708 for broadcast.

Generate Captions

To generate the closed captions:

  1. From the Media Tab, select Generate Captions from the actions menu for a given media record. This is also available from the actions menu in the Media Edit page.
  2. A Captions Generation Options menu will be presented that allows optionally selecting from Custom Language Models to improve caption accuracy, and whether to use Smart Formatting and Profanity Filtering. Additionally you can select one or more Caption Substitutions to automatically find and replace certain text.
  3. Closed Captions generation can also be a Bulk Action:
    1. In the Media Library, check off the videos to be captioned
    2. Select the Bulk Generate Closed Captions action
  4. Closed Captions can also be generated directly from the Assets Tab in the Media Edit page.
  5. Click on the Assets Tab and Scroll down to the Closed Caption section at the bottom of the Assets Tab.
  6. Click the Icon under Actions to begin the process of generating (or regenerating) a closed caption file.Under the Activity tab, you can follow the progress of the caption file creation:
      1. Extracting the audio
      2. Speech-to-Text transcription of the audio
      3. Conversion of the resulting timed text file to the WebVTT format commonly used in VOD streaming.
    1. The overall process is a little faster than real time
    2. When completed, the video thumbnail displays a CC icon. Hovering over the icon will show the types of captioning available, such as WebVTT for VOD files and 608 Embedded for Broadcast files.
  7. Once completed, the Closed Caption file will automatically be attached to any video included in a CloudCast player or OTT app. Additionally, any subsequent Broadcast transcodes will embed the generated captions as 608/708 embedded as long as the “Embed captions in broadcast transcodes” option is enabled. This setting can be managed by an Admin from Administration –> Organization Settings –> Captions. Note that for embedding captions in Broadcast files, the Broadcast transcode must be manually triggered after the caption generation has completed.
  8. To view the captions, the viewer needs to start the video, and then select the CC option in the CloudCast player.
  9. The captions are also viewable in the Preview within Connect. Click the CC icon in the preview player control bar to toggle captions on or off.
  10. The Closed Caption file is available for download from the Assets Tab by clicking the icon under Actions.
  11. The Closed Caption file can be deleted from the Assets Tab by clicking the icon under Actions.
  12. To have captions generated automatically for all uploaded media, enable the configuration option “Auto generation captions for all uploaded files”. This setting can be managed by an Admin from Administration –> Organization Settings –> Captions.

Edit the Captions

The accuracy of any closed caption file depends on the clarity of the speech in the video. If necessary, a closed caption file can be improved with manual editing and re-timing.

One versatile and free open-source caption editing tool is CADET, developed by the National Center for Accessible Media at WGBH. Download the CADET app to your computer and then open in a browser. To edit a caption file:

  1. First, download a preview version of the video from the Assets Tab in TelVue Connect.
  2. Download the captions file from the Assets Tab in TelVue Connect.
  3. Upload the preview video and import the captions file to CADET, and these will be displayed side by side.
  4. You can then edit the text in the individual caption cells.
  5. You can also re-time the in and out points using some simple keyboard shortcuts, as the preview video plays. Refer to the CADET documentation for details.
  6. Re-export the revised caption file.
  7. Re-upload in the Media Edit page in TelVue Connect via the Closed Captioning File – Choose File button. The revised captions will replace the previous file, and will now play out in CloudCast and be available for Broadcast transcodes.


Users can track the usage of their captioning hours at Administration → Reports → Caption Generation Usage Reports.

The TelVue Closed Captioning service can be purchased in blocks of 100, 500, and 1,000 hours. Please contact for pricing.

in CloudCast User ManualConnect User Manual

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