Scratching Audio

I was wondering where to start if I want to implement scratching features in my app. The user selects a sound file, and can see a LP spinning. I want the user to be able to scratch the song like a DJ.

Who can tell me where to start? Or has 开发者_开发技巧some example or something?

Thanks in advance!

Best Regards,

Kenneth

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Check http://www.xwax.co.uk/ for some open source vinyl emulation software.