[FFmpeg-user] Audio normalization using "volume" and "compand"filters
Paul B Mahol
onemda at gmail.com
Thu Nov 28 09:11:16 CET 2013
On 11/27/13, Thierry Lelegard <thierry.lelegard at free.fr> wrote:
> Le 27/11/2013 21:49, Paul B Mahol a ecrit :
> > On 11/27/13, Thierry Lelegard <thierry at lelegard.fr> wrote:
> >> Second problem: The usage of the filter "compand" is extremely obscure.
> >> documentation (http://ffmpeg.org/ffmpeg-filters.html#compand) can hardly
> >> understood if you do not already know the meaning of each parameter.
> >> below some tests I made without deeply understanding what they mean.
> >> [....]
> >> Could someone please explain how to use "compand" and its parameters?
> >> More precisely, how can we compress an input audio with the
> >> in_rms and in_peak into a given target out_rms and out_peak?
> > compand filter is port of sox effect filter of same name.
> > I really doubt that its documentation is obscure.
> This is of course a subjective matter. To make it more objective, the
> is a complete copy/paste of the "compand" documentation from
Why are you pasting documentation? To show you can copy & paste?
> Honestly, how can you get an answer to the above question ("how can we
> compress an input audio with the characteristics in_rms and in_peak into
> a given target out_rms and out_peak?"), using this when you are not an
> expert in audio engineering?
rms and peak are calculated using whole file, so whatever you are trying to
do you are doing it wrong.
> The description of the function transfer using the "points" is not clear.
> Especially when the experimentation gives results which seem inconsistent.
I can not find where you posted valid proof of such statement.
> I do not mean that the filter does not work well. I mean that the way it
> works using the parameters is far from clear. This is why I am looking for
> help in this list.
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