Two of the main problems that an audio engineer fronts while working a tv show, a documentary or any audiovisual that includes dialogue, is the ambient and the recording operator’s skills and disposition.
Sometimes the producer choices an accurate place without background noise, but obviously it’s impossible to control incoming calls or that dummy that came in hitting the door.
Sometimes, after a great interview, at the end of it, the interviewee (a little sorry about it), asks if it wasn’t a problem that the mic fell off a little into his shirt since the beginning. Of course the recording operator denies everything, even when you are hearing pops and clothes rasping all over the audio when you check it.
Sometimes you have to do the trailer of a tv show, but you have to work with the mixed track.
Anyway, the audio engineer has to work with that awful audio and if it still listens awful at the end, he is the one to blame.
This are some examples of audio restoring I’ve made. On most cases it was a complete success. You can here the original and the restored audio.