Some audio tracks are too quiet to be heard comfortably without amplification.
This becomes a problem when your audio equipment cannot amplify the signal for
you. The -softvol
option directs
MPlayer to use an internal mixer. You can then use
the volume adjustment keys (by default 9 and
0) to reach much higher volume levels. Note that this does not
bypass your sound card's mixer; MPlayer only
amplifies the signal before sending it to your sound card.
The following example is a good start:
mplayer quiet-file
-softvol -softvol-max 300
The -softvol-max
option specifies the maximum allowable output
volume as a percentage of the
original volume. For example, -softvol-max 200
would allow the
volume to be adjusted up to twice its original level.
It is safe to specify a large value with
-softvol-max
; the higher volume will not be used until you
use the volume adjustment keys. The only disadvantage of a large value is that,
since MPlayer adjusts volume by a percentage of the
maximum, you will not have as precise control when using the volume adjustment
keys. Use a lower value with -softvol-max
and/or specify
-volstep 1
if you need higher precision.
The -softvol
option works by controlling the
volume
audio filter. If you want to play a file at a certain
volume from the beginning you can specify volume
manually:
mplayer quiet-file
-af volume=10
This will play the file with a ten decibel gain. Be careful when using the
volume
filter - you could easily hurt your ears if you use
too high a value. Start low and work your way up gradually until you get a feel
for how much adjustment is required. Also, if you specify excessively high
values, volume
may need to clip the signal to avoid sending
your sound card data that is outside the allowable range; this will result in
distorted audio.