I just need to mute a few seconds of an audio track that has background noise. I tried to use Audacity as audio editor, but since the audio source is a video/audio, Audacity can't open it. Do I have to extract the audio as a separate track?? I hope not, b/c I would lose the synchronization.
Multiple ways...The better way is to insert a volume envelope and then add in handles that you can drag up and down. You'll need at least 4 points - original volume for track, the place you want to start muting, the last stop for the mute and then another at the time where you want to restore the volume. Look up audio envelope in the help if you need more info.