no sound on movie

downloaded hindi movie girlfriend.2004.xvid-brg using bit torrent stuff...the video quality is great but i have no sound...i donwloaded another movie a week ago also and there was no sound in it either...do i need a codec or something else to get the sound or are these files just messed up..i have xvid and divx already

You need an AC3 filter. U can find it on google