aacpsy: calc_reduction_3gpp() handle active_lines = 0

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

1 files changed, 3 insertions, 0 deletions

diff --git a/libavcodec/aacpsy.c b/libavcodec/aacpsy.c
index 0d44c00cd2..93370b8761 100644
--- a/libavcodec/aacpsy.c
+++ b/libavcodec/aacpsy.c
@@ -526,6 +526,9 @@ static float calc_reduction_3gpp(float a, float desired_pe, float pe,
 {
     float thr_avg, reduction;
 
+    if(active_lines == 0.0)
+        return 0;
+
     thr_avg   = exp2f((a - pe) / (4.0f * active_lines));
     reduction = exp2f((a - desired_pe) / (4.0f * active_lines)) - thr_avg;