OpenELEC Testbuilds for RaspberryPi Part 2
(2013-09-03, 12:22)doveman2 Wrote: Does this make Music the same volume as Movies as currently with Gotham I have to set Music to -30db, which makes it impractical to use XBMC for both Music and Movies as it takes about 60 presses of the volume keys to get from 0 to -30db? Does it also fix the bug where volume jumps to 0db when ffwding/rewinding music until a volume key is pressed?

What amplification does is add an additional boost the volume, that will be removed if clipping would have occurred.

We'll assume that the music you have is encoded full range (we'll refer to that as 0dB), so sounds loud.
We'll assume the movies you have are encoded quietly (we'll refer to that as -30dB).

So, if you set amplification to 30dB, then the movies will be boosted to 0dB, and should sound fine (and loud). You will set your amplifier/TV volume to -30dB to compensate.
The music will be boosted to +30dB which would majorly clip/distort. The DRC scheme should kick in and attenuate the signal by 30dB to stop the clipping. You get 0dB comining out and it should sound similar to movies volume.

However if your music has quiet bits, then they won't clip, and will sound louder than normal. You'll probably be aware of volume increasing and decreasing.
30dB is really too high an amplification value. I believe with xbmc's default amplification scheme, they recommend limiting it to 12 or 15dB otherwise it becomes too noticable.

The scheme is really designed for an action film, than is typically -15dB, but has a gunfight and an explosion that hits 0dB briefly.
You can set the amplification to 15dB, and reduce your TV/receiver volume by the same amount. When the explosion occurs you don't wake up the neighbours.
(It saves you having to juggle the volume on the remote manually).

Currently it only works usefully when xbmc volume is on full as it relies on detecting clipping. You should adjust master volume at tv/receiver.
I think I can make it work with non-full volume.

I think I need to add a decay parameter which can be set to "infinite" for it to work better as a normalisation scheme (doveman2's request), rather than a DRC scheme.


Messages In This Thread
AW: RE: - by DieterLumpen - 2013-07-29, 20:50
include guires switch? - by hpbaxxter - 2013-08-01, 21:46
RE: dual audio?? - by pootler - 2013-08-03, 17:13
Help, watch 3D Film on Non 3D TV - by unix72 - 2013-08-09, 12:39
Remote Controllers - by tfft - 2013-08-14, 09:11
rbej repeatable crash - by RichG - 2013-08-19, 12:43
RE: OpenELEC Testbuilds for RaspberryPi Part 2 - by popcornmix - 2013-09-03, 13:26
New Tester - by theneverstill - 2013-10-03, 17:16