How to add Closed Captions to an Office Mix?

Before you begin, please ensure you have the most recent version of the Office Mix add-in.

If the Office Mix “Update Mix” button is disabled, you have the most recent add-in.
If it’s enabled, select it to download and install the most recent add-in.

NOTE: You might want to set the permissions on your mix to Private while you are experimenting with creating closed captioning. You can find the dialog, in the image above, in your Mix Details page. Once you are ready to share your mix with your audience, reset the permissions of your mix appropriately.

To enable closed captions for a mix, select the option to “Enable playback on mobile devices” during the Upload to Mix workflow. If you have already published your mix, republish it with this checkbox enabled.

Please go to your Office Mix Details page and you will see the Closed Captioning section.

NOTE: If you did not select the option to “Enable playback on mobile devices”, the “Download Video” and “Upload TTML File” links will not be actionable.

Please select the “Download Video” link and import the video into your favorite closed caption tool, or send it to your 3rd party service to generate a TTML (Timed Text markup Language) file.  Office Mix supports a subset of the TTML file format, which is defined in the TTML specification below.

TTML files use a namespace declaration and the language attribute in the root element tt. This is followed by the body and a div element. Within the div element are the timing cues. The actual times are set by the attributes begin and end of the opening paragraph tag <p> and the text is delineated by the closing </p> tag. Blank lines and white space are ignored. We only support single line.

Once the TTML file is ready, please select the “Upload TTML File” link and upload your closed caption file. Now, all that is left to do is preview your mix to ensure that your closed captioning is presented as you intended. If you discover an issue, simply repeat the process described above. Once you are happy with your mix, (re)set the permissions so it is accessible to your audience.


Why are the 'Download Video' and 'Upload to TTML File' text and icons not actionable?
If the 'Download Video' text and icon is disabled, check that you exported a video during the Upload to Mix process by selecting the 'Enable playback on mobile devices' checkbox. Check that you are using the most recent version of the Office Mix add-in.

How do I delete my closed caption?
Please republish your deck. Your closed caption file will no longer be associated with your mix.

Can I generate a TTML based on the Office Mix watch page?
Sorry. You can’t. TTML files are created based on the timings of the video.

Can you recommend any tools that can create TTML files for my Office Mix videos?
Sure. Mix users have had success with a tool called Subtitle Edit. You can download it from here:



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