Adjust the input audio volume.
The filter accepts the following options:
- volume
-
Expresses how the audio volume will be increased or decreased.
Output values are clipped to the maximum value.
The output audio volume is given by the relation:
output_volume = volume * input_volume
Default value for volume is 1.0.
- precision
-
Set the mathematical precision.
This determines which input sample formats will be allowed, which affects the precision of the volume scaling.
- fixed
-
8-bit fixed-point; limits input sample format to U8, S16, and S32.
- float
-
32-bit floating-point; limits input sample format to FLT. (default)
- double
-
64-bit floating-point; limits input sample format to DBL.
Examples
-
Halve the input audio volume:
volume=volume=0.5 volume=volume=1/2 volume=volume=-6.0206dB
In all the above example the named key for volume can be omitted, for example like in:
volume=0.5
-
Increase input audio power by 6 decibels using fixed-point precision:
volume=volume=6dB:precision=fixed