[MPlayer-dev-eng] [PATCH] Set liba52 output volume

[Zoltan Hidvegi]

Nico Sabbi wrote:
> Zoltan Hidvegi wrote:
> 
> >The attached very simple patch adds a new option, -a52volume to set
> >the output level from liba52.
...
> sorry if this question is stupid, but does your patch have anything
> to do with normalization or is it a different thing?

It's different, as the man page patch says, it is almost the same as
using -af volume=<level>, except that it uses the float value before
the int conversion.  Some DVDs have quite low audio levels, and
converting the audio to signed 16-bit and using the volume filter can
discard several significant bits.  To normalize, you can run the
volume filter through the whole file with -af-adv force=4 (which is
btw. undocumented).  If it prints a negative dB level, pass -1 times
that to -a52volume to normalize.  You may also want to set -a52drc 0.

Zoli