diff --git a/mp4/decoder.py b/mp4/decoder.py
index 248ef70..db41e17 100644
--- a/mp4/decoder.py
+++ b/mp4/decoder.py
@@ -58,6 +58,3 @@ class Decoder:
             errstring = libav.strerror(errcode)
             raise Exception(f"Failed to send packet: {errstring}")
         return self._receive()
-
-    def flush(self):
-        return self.decode(None)
diff --git a/mp4/demuxer.py b/mp4/demuxer.py
index f8ae8a6..327b723 100644
--- a/mp4/demuxer.py
+++ b/mp4/demuxer.py
@@ -34,16 +34,16 @@ class Demuxer:
             raise Exception("Failed to find stream info")
         self.video_stream = self._find_stream(libav.AVMEDIA_TYPE_VIDEO)
         if self.video_stream is None:
+            libav.format_close_input(self._context)
             raise Exception("Failed to find a video stream")
         self.audio_stream = self._find_stream(libav.AVMEDIA_TYPE_AUDIO)
         if self.audio_stream is None:
+            libav.format_close_input(self._context)
             raise Exception("Failed to find an audio stream")
 
-    @property
-    def nb_streams(self):
-        if not self._context:
-            return 0
-        return self._context.contents.nb_streams
+    def __del__(self):
+        if self._context:
+            libav.format_close_input(self._context)
 
     def _find_stream(self, type):
         index, codec_ref = libav.format_find_best_stream(self._context, type)
@@ -52,6 +52,12 @@ class Demuxer:
         parameters = self._context.contents.streams[index].contents.codecpar
         return Stream(index, Codec(codec_ref), parameters)
 
+    @property
+    def nb_streams(self):
+        if not self._context:
+            return 0
+        return self._context.contents.nb_streams
+
     def read_packet(self):
         if not self._context:
             return None
@@ -60,7 +66,3 @@ class Demuxer:
         if errcode < 0:
             return None
         return packet
-
-    def close(self):
-        if self._context:
-            libav.format_close_input(self._context)
diff --git a/mp4/libav.py b/mp4/libav.py
index 3895d72..419f019 100644
--- a/mp4/libav.py
+++ b/mp4/libav.py
@@ -50,12 +50,19 @@ class AVCodecParameters(ctypes.Structure):
 
 AVCodecParameters_p = ctypes.POINTER(AVCodecParameters)
 
+class AVRational(ctypes.Structure):
+    _fields_ = [
+        ("num", ctypes.c_int),
+        ("den", ctypes.c_int)]
+
 class AVStream(ctypes.Structure):
     _fields_ = [
         ("av_class", ctypes.c_void_p),
         ("index", ctypes.c_int),
         ("id", ctypes.c_int),
-        ("codecpar", AVCodecParameters_p)]
+        ("codecpar", AVCodecParameters_p),
+        ("priv_data", ctypes.c_void_p),
+        ("time_base", AVRational)]
         # ...
 
 AVStream_p = ctypes.POINTER(AVStream)
diff --git a/mp4/packet.py b/mp4/packet.py
index c077247..bc92f17 100644
--- a/mp4/packet.py
+++ b/mp4/packet.py
@@ -36,9 +36,3 @@ class Packet:
         if self._ref:
             return self._ref.contents.stream_index
         return -1
-
-    @property
-    def pts(self):
-        if self._ref:
-            return self._ref.contents.pts
-        return 0
diff --git a/pve.py b/pve.py
index 765917f..fd66ccb 100644
--- a/pve.py
+++ b/pve.py
@@ -27,23 +27,12 @@ audio_decoder = Decoder(demuxer.audio_stream)
 
 while True:
     packet = demuxer.read_packet()
-    if packet is None:
-        break
-    if demuxer.video_stream.contains(packet):
+    eof = (packet is None)
+    if eof or demuxer.video_stream.contains(packet):
         video_frames = video_decoder.decode(packet)
         print(f"decoded {len(video_frames)} video frames")
-        continue
-    elif demuxer.audio_stream.contains(packet):
+    if eof or demuxer.audio_stream.contains(packet):
         audio_frames = audio_decoder.decode(packet)
         print(f"decoded {len(audio_frames)} audio frames")
-        continue
-    else:
-        print("unkown packet")
-
-video_frames = video_decoder.flush()
-print(f"flushed {len(video_frames)} video frames")
-
-audio_frames = audio_decoder.flush()
-print(f"flushed {len(audio_frames)} audio frames")
-
-demuxer.close()
+    if eof:
+        break