There are some cases where you have to do the impossible: warp a file with no time reference (such as an acapella vocal) such that it lines up with another file (such as a drum track) that has tempo fluctuations.
This means that the vocal track would have to have multiple warp markers to correct the timing, and they need to match those of the drum track exactly. How can this be done? By warping both files simultaneously. Here’s the concept: you warp the drum track, dropping warp markers where necessary and when you’re done, they magically appear in the vocal track as well.
The trick here is to select both clips before you begin warping. (Note: you’re not limited to two clips – this technique will work on as many as you want.) Hold down Shift or Cmd(Mac)/Ctrl(PC) to highlight both clips simultaneously.
Now, take a look at the clip view. Hopefully, it looks like this:
(If the clip view doesn’t look like this, you’ve got a problem I’ll discuss in the next tip.)
Notice that the upper left hand corner reads “2 Clips” and the title bar is striped to let you know there’s a multiple selection in effect. Now take a look at the waveform display. It’s showing the waveform of the clip that was selected last. In this example, this means that you would need to select the clip called Beat second. Otherwise, you’ll be looking at the waveform for the vocal – and that doesn’t do us any good from a warping perspective.
From here on in, it’s simple: just add warp markers the way you normally would and they’ll be added to every selected clip.