Issue
When the host/speakers share PowerPoint presentation with attached video in the slide, the audience can see the video but cannot hear video sound. This is a common issue over most of video conference platforms while using PowerPoint as for live presentation.
Possible solutions
Turn on the speaker and volume up so that video sound can be output and stream in again.
Use Google Slides as a presentation tool. Import PowerPoint slides and upload videos in Google Drive to ensure videos can be played during presentation.
Steps to upload and play video in Google Slides:
1. Click on Insert, select Video from the dropdown list
2. Select insert video source: YouTube, URL or Google Drive
3. Select uploaded video file
4. After inserting video, you should see the video is on the slide
5. If you want to play video during live streaming select Chrome Tab when you share screen. Remember to allow share tab audio.