If I were you I would try this. Youwill get better Quality. http://www.world-import.com/conversion.htm
I can think of three options: 1. Some camcorder have the option to disable sound to be recorded. 2. If you have an external sound connection, plug in an external microphone and tunr that off (plugging in headphones will also do the job ;-) ) 3. Remove the sound later on by editing it out.