Time Stretch function in Soundtrack Pro

By jeff on October 19, 2008 12:29 PM | Permalink | TrackBacks (0)

Soundtrack Pro has a very powerful tool that can stretch or squeeze a piece of audio. Speeding up a slow talking person, or taking a 32 second clip and turning it into a 30 second clip, are the two examples that come to mind when I use the time stretch function.

First step is to open an audio clip in Soundtrack Pro. You should always have the entire length of the clip be the area you need to adjust.

Once the clip is open highlight the entire clip by clicking apple A, and then open the process menu.

After choosing the Time Stretch option you will want to select the Drop Frames format, and enter the desired length into the time window.

After clicking OK, you will only need to save the project at which time you should Save As, and rename the file something slightly different.

I have shown you how to use the time stretch, and now I will show how it integrates with Final Cut Pro. Lets say you have an interview clip where the person on camera is speaking rather slow. Using the time stretch you can speed the clip up, without affecting the pitch of the voice.

To do this first lock the audio track, then adjust speed of the clip by changing the duration length of the video clip. Write the value of what you enter in the duration window, because you will need it again in a minute.

The next step is to unlock the audio and sent it to Soundtrack Pro. To accomplish this, you just right click on the audio clip below the shortened video, and select Send To. When the menu pops out be sure to select Soundtrack Pro Audio File Project, and not Soundtrack Pro Multitrack Project.

Once the clip opens in Soundtrack Pro, go through the same steps as above and the save the project, and it will update in Final Cut Pro. After you trim the excess portion of the audio clip to equal the video, you will have used the time stretch function to successfully speed up the voice without letting it fall out of sync or distort the pitch.

It is important to realize that if you are not applying the time stretch to the entire clip, you will need to check the box to send only the referenced media, and also set the handles to zero. Otherwise Soundtrack Pro will reference the entire clip and the calculations for the Time Stretch function.