For some PowerPoint presentations created on older versions of PowerPoint, Mac users may receive a message of "Codec unavailable" or simply that files don't play when trying to play embedded audio and video, preventing them from listening or watching the clips.
Work around the compatibility issue with these steps:
- Download and install the free VLC media player
- Open the PowerPoint file VLC using the Open menu, which should display a list of all of the media files embedded in it, possibly but not definitely in order
- Open the PowerPoint file in PowerPoint, going through the slides
- View the presentation in PowerPoint and play each media file in VLC when needed (this may take some guess-and-check work)
The author of the file should recreate the media clips using a recent version of PowerPoint, which will use more modern and broadly supported file formats.
The cause of this issue is that older versions of PowerPoint encoded audio and video using the Windows Media codec (making .WMA and .WMV files), which is no longer supported on Macs.
VLC player can play these files, but not the PowerPoint slides themselves.
Recent versions of PowerPoint use the broadly supported MPEG format (making .M4A and .MPG files).