diff --git a/render_mlt.py b/render_mlt.py
index 471f951..2d7c747 100755
--- a/render_mlt.py
+++ b/render_mlt.py
@@ -50,28 +50,30 @@ def add_color(playlist, color, duration):
     red.set_in_and_out(0, duration)
     playlist.append(red)
 
-def add_clip(playlist, file_, in_, duration):
+def add_clip(playlist, clip, in_, duration):
+    file_ = clip['path']
     if not isinstance(file_, str):
         file_ = file_.encode('utf-8')
-    '''
     info = ox.avinfo(file_)
     tractor = mlt.Tractor(profile)
     tracks = tractor.multitrack()
     video = mlt.Playlist()
-    '''
-    clip = mlt.Producer(profile, file_)
-    clip.set_in_and_out(in_, in_+duration-1)
-    playlist.append(clip)
-    '''
-    video.append(clip)
+    c = mlt.Producer(profile, file_)
+    c.set_in_and_out(in_, in_+duration-1)
+    video.append(c)
     tracks.connect(video, 0)
-    if not not info.get('audio'):
+    if not info.get('audio'):
         audio = mlt.Playlist()
         add_silence(audio, duration)
         tracks.connect(audio, 1)
-    #tracks.set_in_and_out(in_, in_+duration-1)
+    else:
+        volume = mlt.Filter(profile, "volume")
+        if clip.get('tag', '') == 'gong':
+            volume.set("gain", '0.8')
+        else:
+            volume.set("gain", '0.12')
+        tractor.plant_filter(volume)
     playlist.append(tractor)
-    '''
 
 def add_audio_clip(playlist, file_, duration):
     in_ = 0
@@ -112,7 +114,7 @@ for clip in data['clips']:
             sys.exit(1)
         # fixme seconds to fps!
         in_ = int(clip['in'] * fps)
-        add_clip(video, clip['path'], in_, frames)
+        add_clip(video, clip, in_, frames)
 add_color(video, 'black', 60)
 
 for clip in data['text']:
@@ -160,9 +162,11 @@ composite = mlt.Transition(profile, "composite")
 
 tractor.plant_transition(composite)
 
+'''
 volume = mlt.Filter(profile, "volume")
 volume.set("gain", '0.12')
 tractor.plant_filter(volume)
+'''
 
 def mix_audio_tracks(a, b, ratio):
     tractor = mlt.Tractor(profile)