Make Existing PowerPoints Accessible
Missing audio or video subtitles
Closed captions and transcripts are essential for Deaf and hard of hearing viewers but benefit everyone. When including video or audio content in PowerPoint, ensure you include a text equivalent via captions or transcripts. The PowerPoint Check Accessibility tool will flag Missing audio or video subtitles as a warning.
Who missing subtitles affects
Statistics suggest 4-5% of the general population experience some form of hearing loss or are Deaf. The number of individuals with hearing loss increases to around 20% for people over age 60. Captions and transcripts are essential for some audiences.
However, 80% of 18 to 25-year-olds regularly use captions when watching video.[1] Educators should consider that captions aid comprehension, focus, and memory[2] and that 90 percent of all students who use closed captions find them helpful for learning.[3] Captions ensure names, terminology, and complex terms are communicated exactly as intended.
Consider the following video as an illustration of why captions are important. Note: ensure captions are turned on and do not adjust the volume on your device.
How to fix it
Missing audio or video subtitles will appear under Media and Illustrations in the Accessibility Assistant pane. While it is essential videos be captioned and audio have a text transcript, this result is considered a warning because PowerPoint cannot determine if a video has no sound and therefore does not require captions or if an audio file has a transcript included later in the presentation or in a linked secondary document. Additionally, PowerPoint does not have the capability to check if an embedded video from YouTube or OneDrive has captions. Missing audio or video subtitles is a reminder to check media for captions and transcripts.
For inserted videos (added via Insert > Video > This Device…) and audio files you must attach a caption file in .VTT format. As a shortcut, select the Missing audio or video subtitles button to add a caption file.
Or:
- Select the video on the slide.
- Move to the Playback tab.
- Select Insert Captions > Insert Captions.
- Choose .VTT file.
Inserting a video file into PowerPoint will increase the overall file size significantly. Consider embedding videos from OneDrive instead. First, add captions to videos on OneDrive. The video will have captions when embedded in PowerPoint.
To embed a OneDrive video:
Get a sharing link from OneDrive by navigating to the video and choosing Share > Copy link.
In PowerPoint:
- Move to the Insert tab.
- Select Video menu.
- Choose Online Video.
- Paste the URL of your OneDrive/SharePoint hosted video and select Insert.
For audio files, consider adding the transcript to a later slide or as an additional document distributed alongside the presentation file. Make a note adjacent to the audio recording indicating where the transcript is available.
How to prevent it next time
Uncaptioned videos are unfinished. Caption your content using YouTube, Kaltura, or OneDrive. Machine-generated captions must be edited for accuracy. When using others’ videos and audio choose captioned content and audio with attached transcripts.
Learn more about how to create and edit closed captions.
Read how to add closed captions or subtitles to media in PowerPoint.
Next
Consider overall file size when inserting video into PowerPoint. Even a short video can increase the size of a PowerPoint 50x. Consider embedding or linking to video content hosted elsewhere.
Move to the next page to examine Slide Titles or select the next error you want to fix.
- Youngs, "Young viewers prefer TV subtitles, research suggests" ↵
- "More than 100 empirical studies document that captioning a video improves comprehension of, attention to, and memory for the video." - Gernsbacher, "Video Captions Benefit Everyone" ↵
- Mary Ellen Dello Stritto and Katie Linder, "A Rising Tide: How Closed Captions Can Benefit All Students" ↵
