demuxer, decoder not working

mp4/demuxer.py

@@ -1,19 +1,42 @@
 # RozK
 
 from . import libav
-from .context import Context
+from .codec import Codec
+from .stream import NullStream, Stream
+from .packet import Packet
 
 class Demuxer:
-    __slots__ = 'context', 'video_stream', 'audio_stream'
+    __slots__ = '_ref', 'video_stream', 'audio_stream'
 
     def __init__(self, path):
-        self.context = Context()
-        self.context.open_input("file:" + path)
-        self.video_stream = self.context.find_stream(libav.AVMEDIA_TYPE_VIDEO)
-        self.audio_stream = self.context.find_stream(libav.AVMEDIA_TYPE_AUDIO)
+        self._ref = libav.format_alloc_context()
+        if not self._ref:
+            raise MemoryError
+        errcode = libav.format_open_input(self._ref, "file:" + path)
+        if errcode < 0:
+            raise Exception(f"Failed to open: {path}")
+        errcode = libav.format_find_stream_info(self._ref)
+        if errcode < 0:
+            libav.format_close_input(self._ref)
+            raise Exception("Failed to find stream info")
+        self.video_stream = self._find_stream(libav.AVMEDIA_TYPE_VIDEO)
+        self.audio_stream = self._find_stream(libav.AVMEDIA_TYPE_AUDIO)
+
+    def _find_stream(self, type):
+        index, codec_ref = libav.format_find_best_stream(self._ref, type)
+        if index < 0 or not codec_ref:
+            return NullStream()
+        return Stream(index, Codec(codec_ref))
 
     def read_packet(self):
-        return self.context.read_packet()
+        if not self._ref:
+            return None
+        packet = Packet()
+        errcode = libav.read_frame(self._ref, packet)
+        if errcode < 0:
+            return None
+        return packet
 
     def close(self):
-        self.context.close_input()
+        if self._ref:
+            libav.format_close_input(self._ref)