Fix possible divide by zero.

Discovered using auto-profile with test file "NAO Kinect control.wmv"

diff --git a/src/modules/normalize/filter_audiolevel.c b/src/modules/normalize/filter_audiolevel.c
index fa8be071c05bd5e232b117b605c787a6486fb9c2..635cdc8a018b7130e60d6be406e72b6aec5f03b5 100644 (file)
--- a/src/modules/normalize/filter_audiolevel.c
+++ b/src/modules/normalize/filter_audiolevel.c
@@ -92,7 +92,7 @@ static int filter_get_audio( mlt_frame frame, void **buffer, mlt_audio_format *f
                                level = 41.0/42.0;
                }
                // max amplitude = 40/42, 3to10  oversamples=41, more then 10 oversamples=42
-               if ( level == 0.0 )
+               if ( level == 0.0 && num_samples > 0 )
                        level = val / num_samples * 40.0/42.0 / 127.0;
                if ( iec_scale )
                        level = IEC_Scale( AMPTODBFS( level ) );