I am having problems recording audio using a RODE video mic pro and Canon 70D DSLR to film. On two occasions, uploading footage to iMovie software audio is clear, but not audible on export. Audio was fine on upload to platform.

Yesterday, problem with audio in Quicktime, iMovie and on export, getting a loud hum in the background at all times. Mic plugged in to jack and set to 1, 20DB boost. Tried file conversion to MP4 and editing using other software but still no audio. Any help/suggestions on why this may be occurring would be appreciated.