[FFmpeg-devel] [PATCH] lavfi: add avolume filter

Michael Niedermayer michaelni at gmx.at
Tue Nov 1 22:53:31 CET 2011


On Tue, Nov 01, 2011 at 09:45:39PM +0100, Stefano Sabatini wrote:
> ---
>  doc/filters.texi         |   42 ++++++++++
>  libavfilter/Makefile     |    1 +
>  libavfilter/af_avolume.c |  189 ++++++++++++++++++++++++++++++++++++++++++++++
>  libavfilter/allfilters.c |    1 +
>  4 files changed, 233 insertions(+), 0 deletions(-)
>  create mode 100644 libavfilter/af_avolume.c
> 
> diff --git a/doc/filters.texi b/doc/filters.texi
> index 7085ae1..9b6f614 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -224,6 +224,48 @@ expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3} @var{c4} @var{c5}
>  @var{c6} @var{c7}]"
>  @end table
>  
> + at section avolume
> +
> +Adjust the input audio volume. The filter accepts exactly one
> +parameter, which express how the audio volume will be increased or
> +decresed.
> +
> +Output values are clipped to the maximum value.
> +
> +If the parameter value is an integer, baseline value is 256, and the
> +output audio volume is given by the relation:
> + at example
> + at var{output_volume}=@var{vol}/256 * @var{input_volume}
> + at end example
> +
> +If the parameter is expressed as a decimal number, baseline value is
> +1.0, and the output audio volume is given by the relation:
> + at example
> + at var{output_volume}=@var{vol} * @var{input_volume}
> + at end example
> +
> +Note that when choosing the decimal number representation, "." must be
> +specified in the parameter or it will be interpreted as an integer
> +value.
> +
> +The expressed value must to be a non-negative value either way.
> +Default parameter value is 1.0.

it should be possible to also specify +-12dB

except that it LGTM, thanks

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Avoid a single point of failure, be that a person or equipment.
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