Overview
All videos that Kaltura ingests are automatically given "machine captions": captions generated by a computer program that provide generally no less than 70% accuracy. Kaltura users can edit these or any captions attached to an entry.
These instructions apply to all Kaltura users at UCSD with active directory credentials (instructors, students, staff, ec.).
Captions can be edited in both Canvas and MediaSpace. Note that while this tutorial will walk you through how to use Kaltura's web-based editor, you can also download your captions and edit them on your computer.
Critical Concepts
What are Captions?
Captions are the textual representation of spoken dialogue, narration, or relevant audio information that display onscreen during a video. While their primary purpose is to make the video more accessible to viewers that may have difficulty hearing, captions benefit many viewers and address a wide variety of learning styles.
Though captions can be "burned into" a video during postproduction (that is, edited directly into the video, rendering them unremovable), generally captions are contained within a separate text file that's formatted in a particular way. Timecodes within the file tell the player when to display the text on screen.
Captions are technically different from transcripts. The latter typically refers to a raw text file just containing the text without any timecodes.
Things to Keep in Mind
- If you edit the captions, the transcript will update too. You may know that many of our Kaltura players within Canvas and MediaSpace have a "transcript widget" beneath the player. The information within this widget, however, comes from the caption file. So if you make changes to your captions, those changes will be reflected immediately in the transcript.
- You can also edit captions on your computer. As mentioned above, you can download your caption file and edit it in a text editor on your computer if you prefer. (Check out our tutorial on editing captions locally if you're interested.)
- If you give someone co-editor access to your video, they can edit your captions. Co-editors of Kaltura videos can follow these instructions as well. (Check out our tutorial on adding collaborators if you need to.) This can come in handy if you want a friend, colleague, or student worker to edit your captions for you.
- Save your changes frequently. Editing captions can be time-consuming. If you spend a long time in the caption editor, there's a chance that your Canvas and/or Kaltura credentials could expire. You won't know this until you attempt to save and you encounter an error message or an instruction to log in again. So click "save" frequently!
- Let us know if you want to add something to the dictionary. You may use words frequently in your videos that Kaltura's ASR vendor isn't aware of. Shoot us an email at kaltura@ucsd.edu if you want us to add something to the dictionary so there's a better chance of the word term being represented correctly next time.
- Zoom integration entries use Zoom's machine captioning system. Currently, Zoom and Kaltura use different systems to generate machine captions. If your Kaltura entry is the result of the Zoom integration (i.e. an entry you originally recorded to the Zoom cloud but ended up in your "My Media" in Canvas or MediaSpace), it will bring over the captions that Zoom generated. This can be nice in some ways because Zoom adds the speaker's name to each line of transcribed text (leveraging the user's UCSD login information).
- Looking for caption editing tips? Editing captions can be time consuming. Check out our tips for editing captions to help make it as quick as possible.
Steps to Take
You can edit your captions on the web in both Canvas and MediaSpace. In either case, you'll need to get to "My Media."
| In Canvas | In MediaSpace |
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- Locate the video whose captions you want to edit, and click the pencil icon in its row.
- Click Captions below the video preview.
- Click Edit Captions. You'll be brought to the Closed Caption Editor.
- Edit your captions. View the information below to learn more about the various actions you can perform.
- Switch between caption files: use the pull-down menu at the top left of the page to select which set of captions you want to edit. If you don't have more than one set of captions, you won't have any options besides the captions you're currently editing.
- Edit caption metadata: Click Edit details to change the language, accuracy percentage, or label. The label is what viewers see when they see caption options within the media player. If you're editing the machine captions, you may want to change the label from "English (auto-generated)" to just "English."
- Find words: Use the field with the magnifying glass to find terms in your captions. Type in a term and press ENTER on your keyboard. All the caption entries that contain the term will be highlighted in yellow.
- Replace words: Click Replace to perform a find-and-replace action in your captions. This feature can save you some time if you use terms that the machine captioning system is repeatedly identifying incorrectly. Be aware that when you perform a replacement, it will replace ALL instances of the word - you won't be able to step through each instance and approve/reject the replacement. You may want to search for the term and see all its instances before performing the bulk replacement.
- Add speaker names: Particularly if you have multiple speakers, it can help some viewers by identifying them in the captions. To add a speaker's name to a line in your captions, click the checkbox on all the rows of captions where you want to add a speaker and click Add speaker. Type the name of the speaker in the dialogue box that appears and click Add speaker. Note that if your entry is the result of the Zoom integration, the speaker's name will already be in the captions.
- Autoscroll through the captions: If the Autoscroll switch is turned on (blue), then the captions will scroll down as you play the video. It will also move to the correct caption line if you skip around in the video using the scrubber within the player.
- Edit timecodes: If you wish, you can click on either a start or end timecode to edit it, which changes when (or how long) the particular caption is displayed onscreen. Generally speaking, this is generally not recommended due to the risk of overlapping your timecodes.
- Edit text: Click on any row of captions within the editor to edit the text. When a row is clicked on, the video preview on the right side of the screen will jump to that part of the video. If you play the video preview, the captions will scroll automatically (unless you un-check the checkbox for "autoscroll").
- Insert a new caption: Move your mouse between any of the caption rows and a button labeled + Add Caption will appear. Click it and you'll be able to insert a caption between the two existing captions. The timecodes will automatically be set to be between the end time of the previous caption and the start time of the following caption.
- When you're done editing your captions, click Save at the top of the page.
- Confirm you want to save your edits by clicking Yes.
- Click Back at the top right of the page to return to the edit page.
Your edits will be reflected immediately in both the captions as well as the transcript.