Using standard mpeg2 or mp4 videos ( Sony Action Cam ) Openshot is not able
to resolve the audio at input.

"could be a problem between ffmpeg and gstreamer1.0-libav and probably
not related to gstreamer plugins not being installed"
Christiaan Welvaart in Bug 8743.

Interestingly it does resolve, input and output, the audio in a mov
file from my Canon EOS camera. I can input that mov file and successfully
output that, video and audio, to an mpeg2 or mp4 video.

Also interestingly if I import the mp4 file to Kino, convert it to DV,
then import that to OpenShot that works just fine audio and video. And
that DV file can be exported to a working, audio and video, mp4 file.