The best way to play a video in a Skype for Business meeting is to insert it in a PowerPoint slide, then upload the PowerPoint to the meeting.
Note: We recommend that video files be less than 50 MB. See Compress the media files in your presentation to solve the issue.
Insert the video in PowerPoint

  - Open PowerPoint in Normal view.
 
  - Click the slide that you want the video to be in.
 
  - On the Insert tab, click the arrow under Video, and then click Video on My PC. 
 

  - In your Skype for Business meeting, click the presentation (monitor) icon, and click Present PowerPoint Files. 
 
  - Click Play to start the video and then Pause to stop.
 
  - Click the speaker icon to change the volume or mute/un-mute the audio.
 
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Important: The audio plays for participants who use computer audio, but not for people on the phone.