Updated readme

README.rst

@@ -21,6 +21,21 @@ Install from `PyPI <https://pypi.python.org/pypi/tidalapi/>`_ using ``pip``:
     $ pip install tidalapi
 
 
+GStreamer
+------------
+
+Playback of certain audio qualities
+Certain streaming qualities require gstreamer bad-plugins, e.g.:
+```
+sudo apt-get install gstreamer1.0-plugins-bad
+```
+This is mandatory to be able to play m4a streams and for playback of mpegdash or hls streams. Otherwise, you will likely get an error:
+```
+WARNING  [MainThread] mopidy.audio.actor Could not find a application/x-hls decoder to handle media.
+WARNING  [MainThread] mopidy.audio.gst GStreamer warning: No decoder available for type 'application/x-hls'.
+ERROR    [MainThread] mopidy.audio.gst GStreamer error: Your GStreamer installation is missing a plug-in.
+```
+
 
 Usage
 -------------