added new UI for python version

Now python users can also enjoy the easy UI

Python Version/pymosh/container/avi.py

@@ -0,0 +1,124 @@
+import struct
+
+from pymosh.codec.mpeg4 import is_iframe
+
+from . import riff
+
+
+class AVIFile(object):
+    """A wrapper for AVI files."""
+
+    def __init__(self):
+        self.riff = riff.RiffIndex()
+        self.streams = []
+        self.frame_order = []
+
+    @staticmethod
+    def from_file(filename: str):
+        instance = AVIFile()
+
+        instance.riff = riff.RiffIndex.from_file(filename=filename)
+
+        header = instance.riff.find(b'LIST', b'hdrl')
+        # Get stream info
+        stream_lists = header.find_all(b'LIST', b'strl')
+        for l in stream_lists:
+            strh = l.find(b'strh')
+            data = strh.data
+            fccType, = struct.unpack(b'4s', data[:4])
+            stream = Stream(len(instance.streams), fccType)
+            instance.streams.append(stream)
+
+        instance.split_streams()
+
+        return instance
+
+    def __iter__(self):
+        return iter(self.streams)
+
+    def add_frame(self, chunk):
+        stream_num = int(chunk.header[:2])
+        if stream_num < len(self.streams):
+            self.frame_order.append(
+                (stream_num, len(self.streams[stream_num])))
+            self.streams[stream_num].add_frame(chunk)
+
+    def split_streams(self):
+        movi = self.riff.find(b'LIST', b'movi')
+        for chunk in movi:
+            self.add_frame(chunk)
+
+    def combine_streams(self):
+        chunks = []
+        for frame_record in self.frame_order:
+            stream_num, frame_num = frame_record
+            stream = self.streams[stream_num]
+            frame = stream[frame_num]
+            chunks.append(frame)
+        return chunks
+
+    def _video(self):
+        return filter(lambda stream: stream.type == b'vids', self.streams)
+    video = property(_video)
+
+    def _audio(self):
+        return filter(lambda stream: stream.type == b'auds', self.streams)
+    audio = property(_audio)
+
+    def rebuild(self):
+        """Rebuild RIFF tree and index from streams."""
+        movi = self.riff.find(b'LIST', b'movi')
+        movi.chunks = self.combine_streams()
+        self.rebuild_index()
+
+    def rebuild_index(self):
+        old_index = self.riff.find(b'idx1')
+        movi = self.riff.find(b'LIST', b'movi')
+        data = b''
+        offset = 0
+        flags = {
+            'base':     0x00000000,
+            'keyframe': 0x00000010,
+        }
+        for chunk in movi:
+            length = len(chunk)
+            frame_flags = flags['base']
+            # If it's a video keyframe or audio frame, use keyframe flag
+            if (chunk.header[2] == b'd' and is_iframe(chunk)) or (chunk.header[2] == b'w'):
+                frame_flags |= flags['keyframe']
+            data += struct.pack(b'<4sIII', chunk.header, frame_flags, offset,
+                                length+8)
+            offset += length + 8 + (length % 2)
+        new_index = riff.RiffDataChunk(b'idx1', data)
+        self.riff.find(b'RIFF').replace(old_index, new_index)
+
+    def write(self, fh):
+        self.riff.write(fh)
+
+
+class Stream(object):
+    def __init__(self, num, stream_type):
+        self.num = int(num)
+        self.type = stream_type
+        self.chunks = []
+
+    def add_frame(self, chunk):
+        self.chunks.append(chunk)
+
+    def __getitem__(self, index):
+        return self.chunks.__getitem__(index)
+
+    def __iter__(self):
+        return self.chunks.__iter__()
+
+    def __len__(self):
+        return len(self.chunks)
+
+    def append(self, *args):
+        return self.chunks.append(*args)
+
+    def extend(self, *args):
+        return self.chunks.extend(*args)
+
+    def replace(self, chunks):
+        self.chunks = chunks