[FFmpeg-devel] [PATCH] lavfi/avf_showspectrum: replace pow(x, 0.25) by sqrt(sqrt(x))

[Ganesh Ajjanagadde]

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

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
---
 libavfilter/avf_showspectrum.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavfilter/avf_showspectrum.c b/libavfilter/avf_showspectrum.c
index accd8c7..cff98ff 100644
--- a/libavfilter/avf_showspectrum.c
+++ b/libavfilter/avf_showspectrum.c
@@ -578,7 +578,7 @@ 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);
-- 
2.6.4