Syncing sound with video velocity speed up

RunnerBrett wrote on 3/13/2013, 9:05 AM

I'm a pretty novice user so please go easy:

I have a video of someone running on a treadmill. I inserted a velocity envelope and gradually sped up the video of the person running. The audio however did not synchronize. The speed of the audio stayed the same.

How can I have the sound of the footsteps increase in speed with the video?

Thanks in advance for any helpful replies :-)

Comments

Chienworks wrote on 3/13/2013, 10:08 AM

It's not at all easy. Vegas doesn't have a velocity envelope for audio. You can adjust it at a constant speed, but not a variable speed. You could try splitting the audio event up into small pieces and then making each subsequent one go a little faster than the one before it (ctrl-stretch/squish the end of the event works well for this) but it will still be hit and miss experimentation to get it right.

Probably a better method is to export the audio to a new .wav file and edit it in Sound Forge, using Pitch/Bend. This effect does let you add an envelope of sorts for a gradual speed up, but it may take you a few tries to get it to match the video closely enough, especially since you won't be listening to the changes while watching the video at the same time.

RunnerBrett wrote on 3/13/2013, 10:42 AM

Thanks for the feedback.

I did split the video and it's "okay". A gradual speed up would be much better.

However, editing the audio in Sound Forge is a great idea. I can do the gradual speed up and when I import it back to Vegas I can use the Ctrl-stretch to match the video.

Great idea - thank you