View Full Version : Sound editing... without the turtle/chipmunk effect...

01-03-2013, 08:20 PM
So, I've been playing a bit with video editing in my spare time and something has occurred to me. It's the issue of the audio when you slow down or speed up the playback of video. I realized that with the advent of programs like AutoTune, that maybe there is a way, mathematically, to extend or shorten the length of the sections of audio so that they don't become distorted by the time scaling. Has anyone come across software, or a plugin that does something like this?

Essentially if you took a slice of the video and did a Fourier Transform of the audio it should show the same frequency amplitude and distribution before and after the scaling...

Ryan Roye
01-03-2013, 10:02 PM
Audacity (http://audacity.sourceforge.net/) is a great, free entry-level software editor that I recommend to anyone who needs all the basic functions of sound editing.

In audacity, you'd look for "Change Tempo", this alters the time of the sound without altering the pitch. "Change pitch" alters the frequency without lengthening or shortening the clip much.

More advanced audio programs like reaper (http://www.reaper.fm/) (what I use now), allow you to alter the qualities of sound much faster, non-destructively, and introduces the options of curve-based editing for even more control. Say you want the pitch, or any effect, to change over time... you can't really do that efficiently in audacity.

01-03-2013, 11:22 PM
time stretch: simple as that!

01-06-2013, 04:28 PM
Very nice. Thanks for the pointers :)