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380 lines
12 KiB
380 lines
12 KiB
from __future__ import division, unicode_literals |
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import base64 |
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import io |
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import itertools |
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import os |
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import time |
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import xml.etree.ElementTree as etree |
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from .fragment import FragmentFD |
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from ..compat import ( |
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compat_urlparse, |
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compat_urllib_error, |
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) |
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from ..utils import ( |
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struct_pack, |
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struct_unpack, |
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xpath_text, |
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) |
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class FlvReader(io.BytesIO): |
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""" |
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Reader for Flv files |
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The file format is documented in https://www.adobe.com/devnet/f4v.html |
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""" |
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# Utility functions for reading numbers and strings |
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def read_unsigned_long_long(self): |
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return struct_unpack('!Q', self.read(8))[0] |
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def read_unsigned_int(self): |
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return struct_unpack('!I', self.read(4))[0] |
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def read_unsigned_char(self): |
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return struct_unpack('!B', self.read(1))[0] |
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def read_string(self): |
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res = b'' |
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while True: |
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char = self.read(1) |
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if char == b'\x00': |
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break |
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res += char |
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return res |
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def read_box_info(self): |
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""" |
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Read a box and return the info as a tuple: (box_size, box_type, box_data) |
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""" |
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real_size = size = self.read_unsigned_int() |
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box_type = self.read(4) |
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header_end = 8 |
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if size == 1: |
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real_size = self.read_unsigned_long_long() |
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header_end = 16 |
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return real_size, box_type, self.read(real_size - header_end) |
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def read_asrt(self): |
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# version |
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self.read_unsigned_char() |
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# flags |
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self.read(3) |
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quality_entry_count = self.read_unsigned_char() |
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# QualityEntryCount |
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for i in range(quality_entry_count): |
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self.read_string() |
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segment_run_count = self.read_unsigned_int() |
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segments = [] |
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for i in range(segment_run_count): |
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first_segment = self.read_unsigned_int() |
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fragments_per_segment = self.read_unsigned_int() |
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segments.append((first_segment, fragments_per_segment)) |
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return { |
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'segment_run': segments, |
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} |
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def read_afrt(self): |
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# version |
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self.read_unsigned_char() |
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# flags |
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self.read(3) |
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# time scale |
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self.read_unsigned_int() |
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quality_entry_count = self.read_unsigned_char() |
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# QualitySegmentUrlModifiers |
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for i in range(quality_entry_count): |
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self.read_string() |
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fragments_count = self.read_unsigned_int() |
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fragments = [] |
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for i in range(fragments_count): |
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first = self.read_unsigned_int() |
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first_ts = self.read_unsigned_long_long() |
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duration = self.read_unsigned_int() |
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if duration == 0: |
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discontinuity_indicator = self.read_unsigned_char() |
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else: |
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discontinuity_indicator = None |
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fragments.append({ |
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'first': first, |
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'ts': first_ts, |
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'duration': duration, |
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'discontinuity_indicator': discontinuity_indicator, |
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}) |
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return { |
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'fragments': fragments, |
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} |
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def read_abst(self): |
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# version |
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self.read_unsigned_char() |
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# flags |
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self.read(3) |
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self.read_unsigned_int() # BootstrapinfoVersion |
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# Profile,Live,Update,Reserved |
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flags = self.read_unsigned_char() |
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live = flags & 0x20 != 0 |
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# time scale |
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self.read_unsigned_int() |
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# CurrentMediaTime |
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self.read_unsigned_long_long() |
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# SmpteTimeCodeOffset |
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self.read_unsigned_long_long() |
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self.read_string() # MovieIdentifier |
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server_count = self.read_unsigned_char() |
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# ServerEntryTable |
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for i in range(server_count): |
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self.read_string() |
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quality_count = self.read_unsigned_char() |
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# QualityEntryTable |
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for i in range(quality_count): |
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self.read_string() |
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# DrmData |
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self.read_string() |
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# MetaData |
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self.read_string() |
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segments_count = self.read_unsigned_char() |
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segments = [] |
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for i in range(segments_count): |
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box_size, box_type, box_data = self.read_box_info() |
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assert box_type == b'asrt' |
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segment = FlvReader(box_data).read_asrt() |
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segments.append(segment) |
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fragments_run_count = self.read_unsigned_char() |
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fragments = [] |
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for i in range(fragments_run_count): |
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box_size, box_type, box_data = self.read_box_info() |
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assert box_type == b'afrt' |
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fragments.append(FlvReader(box_data).read_afrt()) |
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return { |
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'segments': segments, |
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'fragments': fragments, |
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'live': live, |
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} |
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def read_bootstrap_info(self): |
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total_size, box_type, box_data = self.read_box_info() |
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assert box_type == b'abst' |
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return FlvReader(box_data).read_abst() |
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def read_bootstrap_info(bootstrap_bytes): |
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return FlvReader(bootstrap_bytes).read_bootstrap_info() |
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def build_fragments_list(boot_info): |
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""" Return a list of (segment, fragment) for each fragment in the video """ |
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res = [] |
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segment_run_table = boot_info['segments'][0] |
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fragment_run_entry_table = boot_info['fragments'][0]['fragments'] |
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first_frag_number = fragment_run_entry_table[0]['first'] |
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fragments_counter = itertools.count(first_frag_number) |
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for segment, fragments_count in segment_run_table['segment_run']: |
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for _ in range(fragments_count): |
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res.append((segment, next(fragments_counter))) |
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if boot_info['live']: |
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res = res[-2:] |
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return res |
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def write_unsigned_int(stream, val): |
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stream.write(struct_pack('!I', val)) |
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def write_unsigned_int_24(stream, val): |
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stream.write(struct_pack('!I', val)[1:]) |
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def write_flv_header(stream): |
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"""Writes the FLV header to stream""" |
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# FLV header |
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stream.write(b'FLV\x01') |
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stream.write(b'\x05') |
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stream.write(b'\x00\x00\x00\x09') |
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stream.write(b'\x00\x00\x00\x00') |
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def write_metadata_tag(stream, metadata): |
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"""Writes optional metadata tag to stream""" |
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SCRIPT_TAG = b'\x12' |
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FLV_TAG_HEADER_LEN = 11 |
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if metadata: |
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stream.write(SCRIPT_TAG) |
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write_unsigned_int_24(stream, len(metadata)) |
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stream.write(b'\x00\x00\x00\x00\x00\x00\x00') |
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stream.write(metadata) |
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write_unsigned_int(stream, FLV_TAG_HEADER_LEN + len(metadata)) |
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def _add_ns(prop): |
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return '{http://ns.adobe.com/f4m/1.0}%s' % prop |
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class F4mFD(FragmentFD): |
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""" |
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A downloader for f4m manifests or AdobeHDS. |
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""" |
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FD_NAME = 'f4m' |
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def _get_unencrypted_media(self, doc): |
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media = doc.findall(_add_ns('media')) |
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if not media: |
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self.report_error('No media found') |
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for e in (doc.findall(_add_ns('drmAdditionalHeader')) + |
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doc.findall(_add_ns('drmAdditionalHeaderSet'))): |
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# If id attribute is missing it's valid for all media nodes |
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# without drmAdditionalHeaderId or drmAdditionalHeaderSetId attribute |
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if 'id' not in e.attrib: |
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self.report_error('Missing ID in f4m DRM') |
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media = list(filter(lambda e: 'drmAdditionalHeaderId' not in e.attrib and |
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'drmAdditionalHeaderSetId' not in e.attrib, |
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media)) |
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if not media: |
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self.report_error('Unsupported DRM') |
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return media |
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def _get_bootstrap_from_url(self, bootstrap_url): |
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bootstrap = self.ydl.urlopen(bootstrap_url).read() |
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return read_bootstrap_info(bootstrap) |
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def _update_live_fragments(self, bootstrap_url, latest_fragment): |
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fragments_list = [] |
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retries = 30 |
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while (not fragments_list) and (retries > 0): |
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boot_info = self._get_bootstrap_from_url(bootstrap_url) |
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fragments_list = build_fragments_list(boot_info) |
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fragments_list = [f for f in fragments_list if f[1] > latest_fragment] |
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if not fragments_list: |
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# Retry after a while |
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time.sleep(5.0) |
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retries -= 1 |
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if not fragments_list: |
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self.report_error('Failed to update fragments') |
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return fragments_list |
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def _parse_bootstrap_node(self, node, base_url): |
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if node.text is None: |
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bootstrap_url = compat_urlparse.urljoin( |
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base_url, node.attrib['url']) |
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boot_info = self._get_bootstrap_from_url(bootstrap_url) |
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else: |
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bootstrap_url = None |
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bootstrap = base64.b64decode(node.text.encode('ascii')) |
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boot_info = read_bootstrap_info(bootstrap) |
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return (boot_info, bootstrap_url) |
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def real_download(self, filename, info_dict): |
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man_url = info_dict['url'] |
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requested_bitrate = info_dict.get('tbr') |
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self.to_screen('[%s] Downloading f4m manifest' % self.FD_NAME) |
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manifest = self.ydl.urlopen(man_url).read() |
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doc = etree.fromstring(manifest) |
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formats = [(int(f.attrib.get('bitrate', -1)), f) |
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for f in self._get_unencrypted_media(doc)] |
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if requested_bitrate is None: |
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# get the best format |
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formats = sorted(formats, key=lambda f: f[0]) |
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rate, media = formats[-1] |
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else: |
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rate, media = list(filter( |
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lambda f: int(f[0]) == requested_bitrate, formats))[0] |
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base_url = compat_urlparse.urljoin(man_url, media.attrib['url']) |
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bootstrap_node = doc.find(_add_ns('bootstrapInfo')) |
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boot_info, bootstrap_url = self._parse_bootstrap_node(bootstrap_node, base_url) |
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live = boot_info['live'] |
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metadata_node = media.find(_add_ns('metadata')) |
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if metadata_node is not None: |
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metadata = base64.b64decode(metadata_node.text.encode('ascii')) |
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else: |
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metadata = None |
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fragments_list = build_fragments_list(boot_info) |
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if self.params.get('test', False): |
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# We only download the first fragment |
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fragments_list = fragments_list[:1] |
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total_frags = len(fragments_list) |
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# For some akamai manifests we'll need to add a query to the fragment url |
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akamai_pv = xpath_text(doc, _add_ns('pv-2.0')) |
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ctx = { |
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'filename': filename, |
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'total_frags': total_frags, |
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} |
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self._prepare_frag_download(ctx) |
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dest_stream = ctx['dest_stream'] |
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write_flv_header(dest_stream) |
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if not live: |
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write_metadata_tag(dest_stream, metadata) |
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self._start_frag_download(ctx) |
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frags_filenames = [] |
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while fragments_list: |
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seg_i, frag_i = fragments_list.pop(0) |
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name = 'Seg%d-Frag%d' % (seg_i, frag_i) |
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url = base_url + name |
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if akamai_pv: |
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url += '?' + akamai_pv.strip(';') |
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if info_dict.get('extra_param_to_segment_url'): |
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url += info_dict.get('extra_param_to_segment_url') |
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frag_filename = '%s-%s' % (ctx['tmpfilename'], name) |
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try: |
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success = ctx['dl'].download(frag_filename, {'url': url}) |
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if not success: |
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return False |
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with open(frag_filename, 'rb') as down: |
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down_data = down.read() |
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reader = FlvReader(down_data) |
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while True: |
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_, box_type, box_data = reader.read_box_info() |
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if box_type == b'mdat': |
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dest_stream.write(box_data) |
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break |
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if live: |
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os.remove(frag_filename) |
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else: |
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frags_filenames.append(frag_filename) |
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except (compat_urllib_error.HTTPError, ) as err: |
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if live and (err.code == 404 or err.code == 410): |
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# We didn't keep up with the live window. Continue |
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# with the next available fragment. |
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msg = 'Fragment %d unavailable' % frag_i |
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self.report_warning(msg) |
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fragments_list = [] |
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else: |
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raise |
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if not fragments_list and live and bootstrap_url: |
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fragments_list = self._update_live_fragments(bootstrap_url, frag_i) |
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total_frags += len(fragments_list) |
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if fragments_list and (fragments_list[0][1] > frag_i + 1): |
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msg = 'Missed %d fragments' % (fragments_list[0][1] - (frag_i + 1)) |
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self.report_warning(msg) |
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self._finish_frag_download(ctx) |
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for frag_file in frags_filenames: |
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os.remove(frag_file) |
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return True
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