def _create_video_clip(self, chunks, start_offset, stop_offset):
playlist_duration = stop_offset - start_offset
playlist_offset = 0
playlist_streams = []
playlist_tags = []
for chunk in chunks:
chunk_url = chunk["url"]
chunk_length = chunk["length"]
chunk_start = playlist_offset
chunk_stop = chunk_start + chunk_length
chunk_stream = HTTPStream(self.session, chunk_url)
if chunk_start <= start_offset <= chunk_stop:
try:
headers = extract_flv_header_tags(chunk_stream)
except IOError as err:
raise StreamError("Error while parsing FLV: {0}", err)
if not headers.metadata:
raise StreamError("Missing metadata tag in the first chunk")
metadata = headers.metadata.data.value
keyframes = metadata.get("keyframes")
if not keyframes:
if chunk["upkeep"] == "fail":
raise StreamError("Unable to seek into muted chunk, try another timestamp")
else:
raise StreamError("Missing keyframes info in the first chunk")
keyframe_offset = None
keyframe_offsets = keyframes.get("filepositions")
keyframe_times = [playlist_offset + t for t in keyframes.get("times")]
for time, offset in zip(keyframe_times, keyframe_offsets):
if time > start_offset:
break
keyframe_offset = offset
if keyframe_offset is None:
raise StreamError("Unable to find a keyframe to seek to "
"in the first chunk")
chunk_headers = dict(Range="bytes={0}-".format(int(keyframe_offset)))
chunk_stream = HTTPStream(self.session, chunk_url,
headers=chunk_headers)
playlist_streams.append(chunk_stream)
for tag in headers:
playlist_tags.append(tag)
elif start_offset <= chunk_start < stop_offset:
playlist_streams.append(chunk_stream)
playlist_offset += chunk_length
return FLVPlaylist(self.session, playlist_streams,
tags=playlist_tags, duration=playlist_duration)
def _create_video_clip(self, chunks, start_offset, stop_offset):
playlist_duration = stop_offset - start_offset
playlist_offset = 0
playlist_streams = []
playlist_tags = []
for chunk in chunks:
chunk_url = chunk["url"]
chunk_length = chunk["length"]
chunk_start = playlist_offset
chunk_stop = chunk_start + chunk_length
chunk_stream = HTTPStream(self.session, chunk_url)
if chunk_start <= start_offset <= chunk_stop:
try:
headers = extract_flv_header_tags(chunk_stream)
except IOError as err:
raise StreamError("Error while parsing FLV: {0}", err)
if not headers.metadata:
raise StreamError("Missing metadata tag in the first chunk")
metadata = headers.metadata.data.value
keyframes = metadata.get("keyframes")
if not keyframes:
if chunk["upkeep"] == "fail":
raise StreamError("Unable to seek into muted chunk, try another timestamp")
else:
raise StreamError("Missing keyframes info in the first chunk")
keyframe_offset = None
keyframe_offsets = keyframes.get("filepositions")
keyframe_times = [playlist_offset + t for t in keyframes.get("times")]
for time, offset in zip(keyframe_times, keyframe_offsets):
if time > start_offset:
break
keyframe_offset = offset
if keyframe_offset is None:
raise StreamError("Unable to find a keyframe to seek to "
"in the first chunk")
chunk_headers = dict(Range="bytes={0}-".format(int(keyframe_offset)))
chunk_stream = HTTPStream(self.session, chunk_url,
headers=chunk_headers)
playlist_streams.append(chunk_stream)
for tag in headers:
playlist_tags.append(tag)
elif start_offset <= chunk_start < stop_offset:
playlist_streams.append(chunk_stream)
playlist_offset += chunk_length
return FLVPlaylist(self.session, playlist_streams,
tags=playlist_tags, duration=playlist_duration)
