We can now extract the PSSH box from the initalization mp4 to get the Key ID for decryption. Also added re-enabled decryption

utils.py

@@ -0,0 +1,32 @@
+import mp4parse
+import codecs
+import widevine_pssh_pb2
+import base64
+
+def extract_kid(mp4_file):
+    """
+    Parameters
+    ----------
+    mp4_file : str
+        MP4 file with a PSSH header
+
+
+    Returns
+    -------
+    String
+
+    """
+
+    boxes = mp4parse.F4VParser.parse(filename=mp4_file)
+    for box in boxes:
+        if box.header.box_type == 'moov':
+            pssh_box = next(x for x in box.pssh if x.system_id == "edef8ba979d64acea3c827dcd51d21ed")
+            hex = codecs.decode(pssh_box.payload, "hex")
+
+            pssh = widevine_pssh_pb2.WidevinePsshData()
+            pssh.ParseFromString(hex)
+            content_id = base64.b16encode(pssh.content_id)
+            return content_id.decode("utf-8")
+
+    # No Moof or PSSH header found
+    return None