lavfi/avf_showspectrum: replace pow(x, 0.25) by sqrt(sqrt(x))

This is faster; precision assured as result is a float.

Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
This commit is contained in:
Ganesh Ajjanagadde 2016-01-04 18:37:16 -08:00
parent 08339cdb6c
commit 2fbdc4faf1

View File

@ -590,7 +590,7 @@ static int plot_spectrum_column(AVFilterLink *inlink, AVFrame *insamples)
a = cbrt(a);
break;
case FOURTHRT:
a = pow(a, 0.25);
a = sqrt(sqrt(a));
break;
case FIFTHRT:
a = pow(a, 0.20);