diff --git a/libavformat/aiffdec.c b/libavformat/aiffdec.c
index d57ba005ff..1ee3726240 100644
--- a/libavformat/aiffdec.c
+++ b/libavformat/aiffdec.c
@@ -144,6 +144,7 @@ static unsigned int get_aiff_header(AVFormatContext *s, int size,
             aiff->block_duration = 160;
             break;
         default:
+            aiff->block_duration = 1;
             break;
         }
         size -= 4;