diff --git a/over-video.py b/over-video.py
index 6283f30..b4f4b3e 100755
--- a/over-video.py
+++ b/over-video.py
@@ -53,7 +53,7 @@ class CodecPar:
 			else:
 				return []
 		
-		if not self.is_valid(value):
+		if self.is_valid and not self.is_valid(value):
 			raise ValueError("%s is not a valid %s" %(value, self.name))
 		
 		return [self.prefix, value]
@@ -484,7 +484,7 @@ subtitle_codec_router.add_codec(codec_sdrop)
 # see doc/command_assembler.png
 command = over.types.ndict()
 command.identify = Command("ffprobe", "-v", "quiet", "-print_format", "json", "-show_format", "-show_streams", "INFILE")
-command.normalize_prepass = Command("ffmpeg", "CUT_FROM", "-i", "INFILE", "-threads", str(multiprocessing.cpu_count()), "CUT_TO", "MAP", "-filter:a", "loudnorm=i=-23.0:tp=-2.0:lra=7.0:print_format=json", "-f", "null", "/dev/null")
+command.normalize_prepass = Command("ffmpeg", "CUT_FROM", "-i", "INFILE", "-threads", str(multiprocessing.cpu_count()), "CUT_TO", "MAP", "-filter:a", "loudnorm=i=-23.0:tp=-2.0:lra=7.0:print_format=json", "-vn", "-sn", "-f", "null", "/dev/null")
 command.encode_generic = Command("ffmpeg", "FPS", "CUT_FROM", "-i", "INFILE", "-threads", str(multiprocessing.cpu_count()), "CUT_TO", "MAP", "VIDEO", "AUDIO", "SUBTITLE", "OUTFILE")
 command.sub_vfilter = Command("-filter:v", "ARGS")
 command.sub_afilter = Command("-filter:a", "ARGS", "-ar", "48k")
diff --git a/version.py b/version.py
index 0c6abe9..50bc243 100644
--- a/version.py
+++ b/version.py
@@ -4,5 +4,5 @@
 major = 2 # VERSION_MAJOR_IDENTIFIER
 minor = 1 # VERSION_MINOR_IDENTIFIER
 # VERSION_LAST_MM 2.1
-patch = 2 # VERSION_PATCH_IDENTIFIER
+patch = 3 # VERSION_PATCH_IDENTIFIER
 str = ".".join(str(v) for v in (major, minor, patch))