sound won't play in imovie
Hi Everyone, I'm trying to edit a friend's Mp4 video in iMovie version 10.1.14 on an iMac running Mojave 10.14.6. When I open the Mp4 in Quicktime, the audio plays normally and is audible. But after I import the video to iMovie, though I can see the waveform on the timeline, when I play the clip on the timeline, no audio is audible. When I export, there is no audio as well. Anybody have any idea what's going on? Thanks much.
iMac 21.5" 4K, macOS 10.14