Kaltura - Ordering machine captions for media in Kaltura MediaSpace

This document describes how users can order machine captions for media in Kaltura MediaSpace.

Captions for audio or video media make your media more accessible. Machine captions are generated by computer-based speech recognition and can be created for media in MediaSpace. They are approximately 75% accurate depending on content complexity, and should only be used when you review and edit them to increase their accuracy. Inaccurate captions can cause disruption and confusion for the user. Allow 3.5 times the duration of the media to review, edit, and improve their accuracy. Since editing to improve accuracy takes time we recommend you use this tool with shorter recordings.

If you are teaching a student who would benefit from captions, the McBurney Disability Resource Center offers captioning services for students with disabilities. If you have longer or more complex content, request captions reviewed for accuracy by professional caption editors through our recommended vendors. To increase the initial accuracy of machine captions we recommend that you:
  • Use a dedicated microphone (not your built-in laptop microphone) when recording your screencast or webcam if possible.
  • Avoid a noisy recording environment. For example if you have people talking in the background, or a fan, or air conditioning on, it will add noise to the background your recording which will make auto-detection of what you are saying more difficult.
Once you have uploaded your media to Kaltura as described in Kaltura - Uploading Files to Kaltura Mediaspace (UW-Madison) , follow these instructions to request machine captions for your media. You must be the owner of a media item or a co-editor to order machine captions for it:
  1. Launch Chrome or Firefox, go to Kaltura MediaSpace, and login: mediaspace.wisc.edu. If you need more information on how to log in to MediaSpace please see Kaltura - How to Log in to Kaltura MediaSpace (UW-Madison) .
  2. Click on your name or the person silhouette icon in the upper right corner and click My Media:
    Screenshot showing the user having clicked their user icon in Kaltura MediaSpace with the cursor hovering over the drop-down menu option "My Media".
  3. Search for or scroll until you find the media you want to add captions to.
  4. Click on the thumbnail of the media item you want to add captions to.
  5. Click the Actions drop-down menu and select Caption & Enrich:
    A screenshot showing the user having clicked on "Actions" and hovering over "Captions & Enrich" which is outlined in orange.
  6. The Order Captions & Enrichment Services options will display underneath your media item. If you have previously requested machine captions for the media item, it will display here and you can edit them as described in Kaltura - How to edit captions in Kaltura MediaSpace . If you would like to order machine captions and none have been previously ordered, select your options. There are drop-down menu options for
    • Service - select Machine
    • Source Media Language - select the appropriate language. Note that while Arabic, Dutch, English, French, German, Hebrew, Hindi, Italian, Japanese, Korean, Mandarin Chinese, Portugese, Russian, Spanish, Swedish, and Turkish are all available we have not had the opportunity to test the machine captioning accuracy of languages other than English.
    • Feature - select Captions
  7. When you're done selecting your options click the Submit button.
    A screenshot showing the Kaltura MediaSpace "Caption & Enrich" screen. "Existing Requests" is at the top followed by "Order Captions & Enrichment Services." Below this is a message indicating that "Note: Machine captions are on average only 75% accurate. They require editing to increase accuracy, make your media accessible for everyone, and 508 compliance. See the KnowledgeBase article on editing captions for more information." Below the message are dropdowns for "Service" (Machine is selected), "Source Media Language (English is selected), and "Feature" (Captions is selected). At the bottom is a "Submit" button which is outlined in orange.
    At this time you can only request machine captions for a video once so only do this after you are sure you are done making any changes to your video.
  8. The Existing Requests screen will update to show your machine captions pending request order. You should also receive an email notification that indicates a new caption file was added when the machine captions are done processing.
    It usually takes a minimum of 5-10 minutes for machine captions to be processed even for short videos. For longer videos it generally takes about twice the length of the video. Please be aware that during times of heavy usage (like in 2020 during the COVID-19 situation) processing times can lengthen to hours. Keep an eye out for the email notification indicating your machine captions are complete.
  9. If you refresh the window you will need to re-click on Actions and select Caption & Enrich to check when the machine captions are completed. If they are still in process it displays "Processing." Once they are done you'll see the Existing requests will indicate the captions are completed:
    A screenshot showing the "Existing Requests" window. An existing caption request shows a "Request Date" of "09/12/19", "Service" of "Machine", "Feature" of "Captions", "Language" of "English", and "Status" of "Completed."
  10. Captions will not be enabled until you display them. See the instructions below to display captions.

Displaying Captions

We highly encourage you to edit your captions to improve their accuracy. Inaccurate captions can cause confusion for your viewers. To do so, click the pencil icon in the Captions Requests window. Instructions on editing captions are available in Kaltura - How to edit captions in Kaltura MediaSpace .

  1. To show your captions click the Actions drop-down menu and select Edit:
    A screenshot showing the user having clicked the Actions drop-down menu. The cursor hovers over the "Edit" option which is outlined in orange.
  2. Click the Captions tab.
  3. Your machine caption will be listed with the language you previously selected:
    A screenshot showing the Kaltura MediaSpace "Edit → Captions" tab. Two rows of a table are displayed with "Language: English", "Label: English", "File type: SRT", and "Actions" which has a series of 5 icons below it - a check mark (Set as Default), a pecil (Edit), an X (Delete), an arrow pointing down (Download), and a display with a line through it (Show on Player).
    • Click the pencil icon / edit function and update the label for your captions. If the captions are machine captioned and have not been reviewed and edited for accuracy, your label should include "machine captioned" in it. For example "English: machine captioned". This will help indicate that your captions are not as accurate.
    • Once your captions are reviewed for accuracy and the captions are labeled appropriately, publish your captions by clicking the Show on Player icon on the far right to display captions to users.
  4. The complete list of actions you can take on a caption file include from left to right:
    • Screenshot showing the "Set as Default" icon which looks like a check-mark in the "Captions" tab of the "Edit" window. Set as Default - Sets the caption as the default caption for a video.
    • Screenshot showing the "Edit" icon which looks like a pencil in the "Captions" tab of the "Edit" window. Edit - Edit the language and the caption label that displays to viewers. If you click the Edit icon, it will change to a  Save icon which you will need to click after editing the language or label for a caption.
    • Screenshot showing the "Delete" icon which looks like a X in the "Captions" tab of the "Edit" window. Delete - Delete the caption from your media.
    • Screenshot showing the "Download" icon which looks like an arrow pointing down into a computer in the "Captions" tab of the "Edit" window. Download - Download the caption file in .SRT format.
    • Screenshot showing the "Show On Player" icon which looks like a monitor with a line through it in the "Captions" tab of the "Edit" window.Show on Player - Shows the caption as an option for users to display on a video. Machine generated captions are not shown by default so users don't see inaccurate captions. Once you've clicked this the icon will change to a Don't Show on Player icon. 
  5. You may need to refresh your browser window to get the CC button to display on the Kaltura media player. The CC (for Closed Captions)button in the lower right to display the closed captions during playback. Click on CC to display the closed caption options and select English (or the appropriate language) to display them:
    A screenshot showing the lower right of a Kaltura video. The user has clicked on the "CC" button to display the available captions. The cursor hovers over the "English" option.
 

See Also: