Sinusoid has released VideoSpeak, a new Mac OS X app for adding synthesized speech audio tracks to existing videos and movies. It allows you to create a voice-over without the use of a microphone or other audio equipment.

You can use as many voices as you wish within a video -- and even have different voices talking to each other. Novelty voices can be used to add interest to funny videos. VideoSpeak is designed for people producing instructional videos, according to the folks at Sinusoid.

Once the user has finished adding the voice tracks, the video is exported to a QuickTime movie file. The original video is never edited; it's only read and a new video produced with the new synthetic spoken voice tracks.

VideoSpeak uses Apple's Speech Synthesis system for Mac OS X, which has a wide range of voices available as standard from the operating system. In addition to the standard voices, users can download localized voices from Apple with accents for the local language or dialect.

VideoSpeak operates on a range of original video formats. It exports to the QuickTime .mov format.

VideoSpeak 1.0 requires Mac OS X 10.6 or higher. It costs US$5.49 and is available worldwide exclusively through the App Store in the Video category (http://tinyurl.com/csh75uc).