diff --git a/mopidy/audio/actor.py b/mopidy/audio/actor.py
index 834bee55..db923e6d 100644
--- a/mopidy/audio/actor.py
+++ b/mopidy/audio/actor.py
@@ -746,6 +746,7 @@ class Audio(pykka.ThreadingActor):
 
         # Default to blank data to trick shoutcast into clearing any previous
         # values it might have.
+        # TODO: Verify if this works at all, likely it doesn't.
         set_value(Gst.TAG_ARTIST, ' ')
         set_value(Gst.TAG_TITLE, ' ')
         set_value(Gst.TAG_ALBUM, ' ')
diff --git a/mopidy/audio/scan.py b/mopidy/audio/scan.py
index 0b6831ea..c63405b0 100644
--- a/mopidy/audio/scan.py
+++ b/mopidy/audio/scan.py
@@ -137,6 +137,11 @@ def _start_pipeline(pipeline):
 
 
 def _query_duration(pipeline, timeout=100):
+    # 1. Try and get a duration, return if success.
+    # 2. Some formats need to play some buffers before duration is found.
+    # 3. Wait for a duration change event.
+    # 4. Try and get a duration again.
+
     success, duration = pipeline.query_duration(Gst.Format.TIME)
     if success and duration >= 0:
         return duration // Gst.MSECOND