You can add the captions by Kaltura or via Camtasia.

Add the captions by Kaltura

At KTH, you can access Kaltura via https://play.kth.se/

Edit the video and the click on "Captions": Select "Captions"

Click on Upload captions file button

Add captions file menu Click on "Browse" and enter the filename/select the file.

Now set the attributes of the caption: Set attributes of captions

Note that the name you enter in the "Label" box, will be the label that will be shown if you click on the closed caption button on the viewer, as seen below:

Kaltura captions label

The final result with captions is:

Kaltura showing captions

After some time the captions will be added.

You can find a full example of a video with captions at Degree projects -helpful hints.

Add the captions via Camtasia

Go to the Captions menu, then click on the little gear symbol and you will get a pulldown menu, select Import Captions:

Camtasia import captions

Now you can "Share" the project to generate the files including a video with the captions embedded into it.

TechSmith has a tutorial on manually adding captions and editing them in Camtasia at https://www.techsmith.com/tutorial-camtasia-manually-add-captions-to-a-video.html

The video above shows you how to use a nice set of widgets to replay the audio for a caption, forward to the next caption, back to the previous, etc.