There’s been a few reports since we released Plex/7 that the volume of movies is much quieter than usual, and quieter than other apps playing the same movie. Elan and I have been tossing around a few theories about why, and what the answer is.
There are a few ways to solve it. The first is simply to “make the volume go to 11.” Unfortunately its not quite that easy, as you can’t amplify a digital signal above 100% without introducing clipping and distortion.
A solution common in the recording industry is to use Dynamic Range Compression (DRC), which amplifies the quiet sections of audio to match the louder sections. This is an acceptable solution for some, but I prefer to avoid it because you lose audio quality as you decrease the dynamic range available.
The third way is volume normalisation (what iTunes does when you choose Sound Check). Lets say you have a movie with an average volume of 50% of maximum, and peaks during action sequences which reach 70% of maximum. We can safely amplify this audio track by 30% without introducing clipping, and with no loss in dynamic range.
This is exactly what the next release of Plex will do, tracking the current signal in real time and amplifying it as much as possible without clipping. I’ve allowed a maximum amplication of 10dB so that you don’t blow up your speakers with silence.
Enjoy, and as always, polite and detailed feedback is welcome.