diff --git a/NEWS b/NEWS
index 1dd096e89..af6063588 100644
--- a/NEWS
+++ b/NEWS
@@ -1,4 +1,5 @@
 ver 0.16.3 (2011/??/??)
+* fix assertion failure in audio format mask parser
 
 
 ver 0.16.2 (2011/03/18)
diff --git a/src/audio_parser.c b/src/audio_parser.c
index ca5182c4a..139cf1c04 100644
--- a/src/audio_parser.c
+++ b/src/audio_parser.c
@@ -192,7 +192,8 @@ audio_format_parse(struct audio_format *dest, const char *src,
 	}
 
 	audio_format_init(dest, rate, sample_format, channels);
-	assert(audio_format_valid(dest));
+	assert(mask ? audio_format_mask_valid(dest)
+	       : audio_format_valid(dest));
 
 	return true;
 }