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# Audio Tools, a module and set of tools for manipulating audio data
# Copyright (C) 2007-2015 Brian Langenberger
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
from audiotools._ogg import PageReader, PageWriter, Page
class PacketReader(object):
def __init__(self, pagereader):
"""pagereader is a PageReader object"""
self.__pagereader__ = pagereader
self.__page__ = Page(packet_continuation=0,
stream_beginning=0,
stream_end=0,
granule_position=0,
bitstream_serial_number=0,
sequence_number=0,
segments=[])
self.__current_segment__ = 1
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.close()
def read_segment(self):
if self.__current_segment__ >= len(self.__page__):
self.read_page()
segment = self.__page__[self.__current_segment__]
self.__current_segment__ += 1
return segment
def read_page(self):
self.__page__ = self.__pagereader__.read()
self.__current_segment__ = 0
return self.__page__
def read_packet(self):
"""returns next Ogg packet as a string"""
segments = []
segment = self.read_segment()
segments.append(segment)
while len(segment) == 255:
segment = self.read_segment()
segments.append(segment)
return b"".join(segments)
def close(self):
"""closes stream for further reading"""
self.__pagereader__.close()
def packet_to_segments(packet):
if len(packet) == 0:
yield b""
else:
while len(packet) > 0:
if len(packet) == 255:
yield packet
yield b""
packet = b""
else:
yield packet[0:255]
packet = packet[255:]
def packet_to_pages(packet, bitstream_serial_number,
starting_sequence_number=0):
"""given a string of packet data,
yields a Page object per Ogg page necessary to hold that packet
packet_continuation is filled in as needed
stream_beginning and stream_end are False
granule_position is 0
sequence_number increments starting from "starting_sequence_number"
"""
from audiotools._ogg import Page
page = Page(
packet_continuation=False,
stream_beginning=False,
stream_end=False,
granule_position=0,
bitstream_serial_number=bitstream_serial_number,
sequence_number=starting_sequence_number,
segments=[])
for segment in packet_to_segments(packet):
if page.full():
yield page
starting_sequence_number += 1
page = Page(
packet_continuation=True,
stream_beginning=False,
stream_end=False,
granule_position=0,
bitstream_serial_number=bitstream_serial_number,
sequence_number=starting_sequence_number,
segments=[])
page.append(segment)
yield page
def packets_to_pages(packets, bitstream_serial_number,
starting_sequence_number=0):
"""given an iterable of packet data strings,
yields a Page object per Ogg page necessary to hold those packets
packet_continuation is filled in as needed
stream_beginning and stream_end are False
granule_position is 0
sequence_number increments starting from "starting_sequence_number"
"""
from audiotools._ogg import Page
page = Page(
packet_continuation=False,
stream_beginning=False,
stream_end=False,
granule_position=0,
bitstream_serial_number=bitstream_serial_number,
sequence_number=starting_sequence_number,
segments=[])
for packet in packets:
for (i, segment) in enumerate(packet_to_segments(packet)):
if page.full():
yield page
starting_sequence_number += 1
page = Page(
packet_continuation=(i != 0),
stream_beginning=False,
stream_end=False,
granule_position=0,
bitstream_serial_number=bitstream_serial_number,
sequence_number=starting_sequence_number,
segments=[])
page.append(segment)
yield page
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