Hello megalles - Welcome to the Sony Forums

First of all, if this is happening on all of your recorded videos this may indicate an internal fault within the camera - can you hear the buzzing when you play the video back on the camera screen?

If you need to 'clean up' the audio from a recorded video, in the past I have used a free piece of software called Audacity which is available here:

http://audacity.sourceforge.net/

Once you have extracted the sound file from your video clip i.e. as an mp3, you can pick a 'clean' section of the audio and apply the settings to the whole clip by using the 'Noise Removal' feature. This can be a little 'hit and miss' sometimes but it depends on how prominent the buzzing is.

Alternatively, this may be available as part of some video editing packages.

Thanks,

Simon