Xvid/AC3 encoded video file volume too low

Does anybody know what I can do to make it sound louder? My mp3s and other sound files play perfectly so I’m sure its not a speaker have less power issue. Everything is fine for example sound in games and DVDs is perfectly alright. I see there is a AC3 icon in the control panel but I’m not sure on how to use it.

Can anybody drop a solution?

Thanks

MP3 has 2 channels, AC3 normally more.
It is just perfectly normal that AC3 seems to sound quieter.

To make use of AC3, you have to connect suitable 5.1 speakers to your computer/soundcard. Anything else works with downsampling.