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

Nicolas George nicolas.george at normalesup.org
Wed Nov 2 09:24:39 CET 2011


Le duodi 12 brumaire, an CCXX, Stefano Sabatini a écrit :
> + at var{output_volume} = 10^(@var{vol}/10) * @var{input_volume}

Unless I am mistaken, the formula should be 10^(vol/20): the decibels are
measured on the power, which is proportional to the square of the linear
volume. If the volume is multiplied by 10, its square is multiplied by 100,
thus +20dB.

At the very least, that is how mplayer does it.

Regards,

-- 
  Nicolas George
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