Speeding up a talking-head video by 5 to 10% can make it more lively and interesting. When doing this, it is important to preserve the pitch of any spoken audio so that it doesn’t distort the speaker’s voice.
As has been explained by others, this can be done by stripping out the audio and changing the tempo in Audacity before reinserting it back in Camtasia after adjusting the duration of the video.
As I mentioned in an earlier post, it is tiresome to do this as it adds several more steps to the video production process, especially as it can be quite difficult synchronising the lip movements with the audio track.
I am amazed that this is not included as a standard feature in Camtasia for Windows, especially considering the cost of the regular upgrades!
I have discovered that this is done quite simply in a competing product as shown in this video clip: https://www.youtube.com/watch?v=X3QOB_gCf3I
Hopefully seeing how easily this can be done by others will spur Techsmith into adding the same capability to Camtasia.