>I also do not get an audio preview along with my video preview (when i
AE does not support audio playback in realtime. You have to generate proper RAM previews. As for your other issue - is your footage interpretation correct? If e.g. fields are not set correctly, you will see flicker 'cos the masks would not align perfectly. Also consider pre-composing your footage. Sometimes with compressed formats processing the masks directly on the footage will result in oddities.