diff --git a/libaf/format.c b/libaf/format.c
index 1427f232f1..cb795ee362 100644
--- a/libaf/format.c
+++ b/libaf/format.c
@@ -74,6 +74,7 @@ int af_str2fmt(const char* str)
 
 int af_fmt2bits(int format)
 {
+    if (AF_FORMAT_IS_AC3(format)) return 16;
     return (format & AF_FORMAT_BITS_MASK)+8;
 //    return (((format & AF_FORMAT_BITS_MASK)>>3)+1) * 8;
 #if 0