diff --git a/bin/ffx/file_properties.py b/bin/ffx/file_properties.py
index b44fe9b..d0106b9 100644
--- a/bin/ffx/file_properties.py
+++ b/bin/ffx/file_properties.py
@@ -211,13 +211,8 @@ class FileProperties():
 
 
     def getMediaDescriptor(self):
-
         return MediaDescriptor.fromFfprobe(self.getFormatData(), self.getStreamData())
 
-        # formatData = self.getFormatData()
-        # streamData = self.getStreamData()
-
-
 
     def getShowId(self) -> int:
         return self.__pattern.getShowId() if self.__pattern is not None else -1
diff --git a/bin/ffx/media_descriptor.py b/bin/ffx/media_descriptor.py
index e1d1a61..cab7054 100644
--- a/bin/ffx/media_descriptor.py
+++ b/bin/ffx/media_descriptor.py
@@ -1,43 +1,81 @@
+from typing import List
+
 from ffx.track_type import TrackType
 from ffx.track_descriptor import TrackDescriptor
 
 
 class MediaDescriptor():
     """This class represents the structural content of a media file including streams and metadata"""
-    
+
+    TAGS_KEY = 'tags'
+    TRACK_DESCRIPTORS_KEY = 'track_descriptors'
+    CLEAR_TAGS_KEY = 'clear_tags'
+
+    FFPROBE_DISPOSITION_KEY = 'disposition'
+    FFPROBE_TAGS_KEY = 'tags'
+    FFPROBE_CODEC_TYPE_KEY = 'codec_type'
+
+
     def __init__(self, **kwargs):
 
-        self.__mediaTags = kwargs['tags'] if 'tags' in kwargs.keys() else {}
-        self.__trackDescriptors = kwargs['trackDescriptors'] if 'trackDescriptors' in kwargs.keys() else {}
-        self.__clearTags = kwargs['clearTags'] if 'clearTags' in kwargs.keys() else False
+        if MediaDescriptor.TAGS_KEY in kwargs.keys():
+                if type(kwargs[MediaDescriptor.TAGS_KEY]) is not dict:
+                        raise TypeError(f"MediaDescriptor.__init__(): Argument {MediaDescriptor.TAGS_KEY} is required to be of type dict")
+                self.__mediaTags = kwargs[MediaDescriptor.TAGS_KEY]
+        else:
+                self.__mediaTags = {}
+
+        if MediaDescriptor.TRACK_DESCRIPTORS_KEY in kwargs.keys():
+                # if type(kwargs[MediaDescriptor.TRACK_DESCRIPTORS_KEY]) is not List[TrackDescriptor]: # Use List typehint for TrackDescriptor as well if it works
+                #         raise TypeError(f"MediaDescriptor.__init__(): Argument {MediaDescriptor.TRACK_DESCRIPTORS_KEY} is required to be of type list containing only elements of type TrackDescriptor")
+
+                if type(kwargs[MediaDescriptor.TRACK_DESCRIPTORS_KEY]) is not dict: # Use List typehint for TrackDescriptor as well if it works
+                        raise TypeError(f"MediaDescriptor.__init__(): Argument {MediaDescriptor.TRACK_DESCRIPTORS_KEY} is required to be of type dict")
+                # for d in kwargs[MediaDescriptor.TRACK_DESCRIPTORS_KEY]:
+                #         if type(d) is not TrackDescriptor:
+                #                 raise TypeError(f"TrackDesciptor.__init__(): All elements of argument set {MediaDescriptor.TRACK_DESCRIPTORS_KEY} is required to be of type TrackDescriptor")
+                self.__trackDescriptors = kwargs[MediaDescriptor.TRACK_DESCRIPTORS_KEY]
+        else:
+                self.__trackDescriptors = set()
+
+        if MediaDescriptor.CLEAR_TAGS_KEY in kwargs.keys():
+                if type(kwargs[MediaDescriptor.CLEAR_TAGS_KEY]) is not bool:
+                        raise TypeError(f"MediaDescriptor.__init__(): Argument {MediaDescriptor.CLEAR_TAGS_KEY} is required to be of type bool")
+                self.__clearTags = kwargs[MediaDescriptor.CLEAR_TAGS_KEY]
+        else:
+                self.__clearTags = False
 
 
     @classmethod
     def fromFfprobe(cls, formatData, streamData):
 
-        descriptors = {}
+        trackDescriptors = {}
 
         for streamObj in streamData:
 
-            trackType = TrackType.fromLabel(streamObj['codec_type'])
+            trackType = TrackType.fromLabel(streamObj[MediaDescriptor.FFPROBE_CODEC_TYPE_KEY])
 
             if trackType != TrackType.UNKNOWN:
 
-                if trackType.label() not in descriptors.keys():
-                    descriptors[trackType.label()] = []
+                if trackType.label() not in trackDescriptors.keys():
+                    trackDescriptors[trackType.label()] = []
+
+                trackDescriptors[trackType.label()].append(TrackDescriptor.fromFfprobe(streamObj))
 
-                descriptors[trackType.label()].append(TrackDescriptor.fromFfprobe(streamObj))
+        kwargs = {}
+        if MediaDescriptor.FFPROBE_TAGS_KEY in formatData.keys():
+              kwargs[MediaDescriptor.TAGS_KEY] = formatData[MediaDescriptor.FFPROBE_TAGS_KEY]
+        kwargs[MediaDescriptor.TRACK_DESCRIPTORS_KEY] = trackDescriptors
 
-        return cls(tags=formatData['tags'] if 'tags' in formatData.keys() else {},
-                    trackDescriptors = descriptors)
+        return cls(**kwargs)
 
 
     def getTags(self):
         return self.__mediaTags
 
 
-    def getAudioTracks(self):
+    def getAudioTracks(self) -> List[TrackDescriptor]:
         return self.__trackDescriptors[TrackType.AUDIO.label()] if TrackType.AUDIO.label() in self.__trackDescriptors.keys() else []
 
-    def getSubtitleTracks(self):
+    def getSubtitleTracks(self) -> List[TrackDescriptor]:
         return self.__trackDescriptors[TrackType.SUBTITLE.label()] if TrackType.SUBTITLE.label() in self.__trackDescriptors.keys() else []
diff --git a/bin/ffx/pattern_controller.py b/bin/ffx/pattern_controller.py
index 3dc74ba..b3935de 100644
--- a/bin/ffx/pattern_controller.py
+++ b/bin/ffx/pattern_controller.py
@@ -134,8 +134,6 @@ class PatternController():
         finally:
             s.close()
 
-        return result
-    
 
     def getMediaDescriptor(self, patternId):