Do-it-Yourself ADR

[Seeker47]

a.k.a. Looping.
I have a video clip, and I'd like to replace a couple lines of dialgue. The lip-synch does not need to be great. (Think in terms of the early Woody Allen flick "What's Up, Tiger Lilly ?") What is the easiest way to do this, with halfway decent results ? I'm afraid you're going to tell me this will require a demux / remux among other things, but if that is unavoidable, so be it. I already have Audacity installed, for whatever that may be worth. Still hoping to find a nice guide for that one . . . or maybe even for this little project.

[Forum Troll]

Watch the original clip with the sound muted, at the same time record your dialog to match their lip movements as closely as possible. Then you can add silence before or after the bits you recorded to get the sync right. You can then mux your soundtrack together with the original video.

[Seeker47]

Watch the original clip with the sound muted, at the same time record your dialog to match their lip movements as closely as possible. Then you can add silence before or after the bits you recorded to get the sync right. You can then mux your soundtrack together with the original video.

So then it gets overlaid ? What happens to the original word(s) ? Wouldn't that be like more than one person talking at the same time ?

I was hoping for more step-by-step detail on doing this.