Have you ever watched a movie where the dialogue was almost inaudible, but then all of a sudden an action scene comes in and shakes your house with noise? Here's how to fix that problem in VLC.
While these volume changes exist to make the movie more immersive, they can be really annoying if you have sleeping kids, or neighbors that like to file noise complaints against you all the time. The fix is something called dynamic range compression, and it's available in VLC. You may have to play around with the settings a bit, but in general, here are some good settings to tweak (courtesy of some fellows over at Reddit):
Head to Tools > Effects and Filters and click on the Compressor tab.
Without changing your TV's volume from its usual spot, find a quiet scene in the movie and raise the Makeup Gain slider until the volume is at a comfortable level. This will boost the volume of the entire movie so you don't have to change your TV or computer's volume from its usual setting.
Raise the Ratio slider all the way up. This will ensure that any sound over a certain volume threshold will be turned down to a level you set.
Without changing the volume, find a loud scene in the movie and start playing it. Lower the Threshold slider until the sound is at a non-earthquake-inducing level.
Lastly, move "Attack" up to about 50ms, and "Release" up to about 300ms. This makes everything a bit more fluid, so your movie will change volumes when necessary but it will happen a bit more gradually.
Now try watching your movie. You should notice that, without changing your volume from its usual spot, the dialogue is much easier to hear, but the action scenes stay at an appropriate level. You may have to go back and fiddle with the settings to get everything just right, but it's an invaluable feature for those of us that want to keep the noise level down. Check out the video above for a demonstration using The Matrix, one of the worst offenders of this phenomenon, or hit the link to read more.
Update: It looks like XBMC has a version of this feature as well, for you home theater PC geeks. Huzzah! Thanks to @theediguy for sending this in.
Update 2: You can also use an app like Sound Lock to achieve a similar effect.
[LPT] Watching a movie and the dialogue is too quiet and the action too loud? | Reddit