on occasion i will come across some great quality mpeg movies with almost perfect sound. the reason i say almost perfect is that when playing back some movies (this has happened on more than one occasion) there are occasional 'spikes' of high frequency sound. it almost sounds like about every ten minutes somebody scratches their fingernails on a chalkboard for a split second.

...are there any programs or suggestions on how i might be able to fix the audio in movies such as these?