The new DVD of the animation movie Shrek features a computer program that lets you dub your voice to different characters in the movie.
As you read the on-screen script into a microphone the program automatically synchronises your voice with the lip movements of the character you have chosen to play.
Professional software called VocALign either stretches or shrinks your voice recording to match the character鈥檚 lip movements without affecting the pitch of your voice. When the scene is played back the character will appear to speak with your voice.
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Normally, movie makers use VocALign to dub an actor鈥檚 voice over a scene where the sound quality of the original recording was poor. The software works by comparing two audio tracks of the same words and using the characteristic waveform of the words to 鈥渨arp鈥� the studio recording to match the original.
When the Shrek DVD is played on a Windows PC it automatically installs interactive control software called InterActual PC Friendly, and a stripped-down version of VocALign. This means you can select 12 scenes from the movie, and read the animated characters鈥� lines, a bit like karaoke.
The PC records the new voice onto its hard disc and warps the sound to fit the character鈥檚 lips. Several people can record the lines for different characters. Next time you play the movie sequences the new voiceovers will replace the actors鈥� voices.
And if you鈥檙e not happy with your starring role, you can always go back to the original. The movie will play normally, without the feature, on home DVD players.