How to apply replaygain 2011-11-06 22:17:36 Hi,I|m programming a music player for my touchscreen Windows UMPC. I use Qt/QML for the UI so I decided to use Phonon as playback backend, which on Windows uses DirectShow to decode audio. Because Phonon/DirectShow doesn't support replaygain, I decided to implement it myself.What I do is to scan all the tracks to database including RG tags (files are tagged by foobar2000). Then when a new track starts playing I change the volume using setVolumeDecibel function. Everything seems to work fine, but the result is simply wrong. The tracks that should be quieten are to quiet and amplified tracks are to loud.I'm still quite lost in understanding what a decibel value means. According to my knowledge a value of 10 dB (some sources say 6 dB) means twice as loud (perceived by human ears) and 10 times higher real output. Some of my tracks have RG values close to -10 dB and others up to 6 dB. This indicates a huge difference in volume of the tracks. But I think this is normal.Anyway could someone explain me please, what might be the cause of the phenomenon, that applying RG changes the volume to much? The practical solution would be probably to divide the RG values by 2. But I want to know why there is a problem and why it doesn't work as I expected. In other players replaygain works OK and all my tracks sound equally loud.