Raphaël G. Git Repositories - youtubedl/blob - youtube_dl/downloader/f4m.py

   1 from __future__ import division, unicode_literals
   2
   3 import base64
   4 import io
   5 import itertools
   6 import os
   7 import time
   8
   9 from .fragment import FragmentFD
  10 from ..compat import (
  11     compat_etree_fromstring,
  12     compat_urlparse,
  13     compat_urllib_error,
  14     compat_urllib_parse_urlparse,
  15 )
  16 from ..utils import (
  17     encodeFilename,
  18     sanitize_open,
  19     struct_pack,
  20     struct_unpack,
  21     xpath_text,
  22 )
  23
  24
  25 class FlvReader(io.BytesIO):
  26     """
  27     Reader for Flv files
  28     The file format is documented in https://www.adobe.com/devnet/f4v.html
  29     """
  30
  31     # Utility functions for reading numbers and strings
  32     def read_unsigned_long_long(self):
  33         return struct_unpack('!Q', self.read(8))[0]
  34
  35     def read_unsigned_int(self):
  36         return struct_unpack('!I', self.read(4))[0]
  37
  38     def read_unsigned_char(self):
  39         return struct_unpack('!B', self.read(1))[0]
  40
  41     def read_string(self):
  42         res = b''
  43         while True:
  44             char = self.read(1)
  45             if char == b'\x00':
  46                 break
  47             res += char
  48         return res
  49
  50     def read_box_info(self):
  51         """
  52         Read a box and return the info as a tuple: (box_size, box_type, box_data)
  53         """
  54         real_size = size = self.read_unsigned_int()
  55         box_type = self.read(4)
  56         header_end = 8
  57         if size == 1:
  58             real_size = self.read_unsigned_long_long()
  59             header_end = 16
  60         return real_size, box_type, self.read(real_size - header_end)
  61
  62     def read_asrt(self):
  63         # version
  64         self.read_unsigned_char()
  65         # flags
  66         self.read(3)
  67         quality_entry_count = self.read_unsigned_char()
  68         # QualityEntryCount
  69         for i in range(quality_entry_count):
  70             self.read_string()
  71
  72         segment_run_count = self.read_unsigned_int()
  73         segments = []
  74         for i in range(segment_run_count):
  75             first_segment = self.read_unsigned_int()
  76             fragments_per_segment = self.read_unsigned_int()
  77             segments.append((first_segment, fragments_per_segment))
  78
  79         return {
  80             'segment_run': segments,
  81         }
  82
  83     def read_afrt(self):
  84         # version
  85         self.read_unsigned_char()
  86         # flags
  87         self.read(3)
  88         # time scale
  89         self.read_unsigned_int()
  90
  91         quality_entry_count = self.read_unsigned_char()
  92         # QualitySegmentUrlModifiers
  93         for i in range(quality_entry_count):
  94             self.read_string()
  95
  96         fragments_count = self.read_unsigned_int()
  97         fragments = []
  98         for i in range(fragments_count):
  99             first = self.read_unsigned_int()
 100             first_ts = self.read_unsigned_long_long()
 101             duration = self.read_unsigned_int()
 102             if duration == 0:
 103                 discontinuity_indicator = self.read_unsigned_char()
 104             else:
 105                 discontinuity_indicator = None
 106             fragments.append({
 107                 'first': first,
 108                 'ts': first_ts,
 109                 'duration': duration,
 110                 'discontinuity_indicator': discontinuity_indicator,
 111             })
 112
 113         return {
 114             'fragments': fragments,
 115         }
 116
 117     def read_abst(self):
 118         # version
 119         self.read_unsigned_char()
 120         # flags
 121         self.read(3)
 122
 123         self.read_unsigned_int()  # BootstrapinfoVersion
 124         # Profile,Live,Update,Reserved
 125         flags = self.read_unsigned_char()
 126         live = flags & 0x20 != 0
 127         # time scale
 128         self.read_unsigned_int()
 129         # CurrentMediaTime
 130         self.read_unsigned_long_long()
 131         # SmpteTimeCodeOffset
 132         self.read_unsigned_long_long()
 133
 134         self.read_string()  # MovieIdentifier
 135         server_count = self.read_unsigned_char()
 136         # ServerEntryTable
 137         for i in range(server_count):
 138             self.read_string()
 139         quality_count = self.read_unsigned_char()
 140         # QualityEntryTable
 141         for i in range(quality_count):
 142             self.read_string()
 143         # DrmData
 144         self.read_string()
 145         # MetaData
 146         self.read_string()
 147
 148         segments_count = self.read_unsigned_char()
 149         segments = []
 150         for i in range(segments_count):
 151             box_size, box_type, box_data = self.read_box_info()
 152             assert box_type == b'asrt'
 153             segment = FlvReader(box_data).read_asrt()
 154             segments.append(segment)
 155         fragments_run_count = self.read_unsigned_char()
 156         fragments = []
 157         for i in range(fragments_run_count):
 158             box_size, box_type, box_data = self.read_box_info()
 159             assert box_type == b'afrt'
 160             fragments.append(FlvReader(box_data).read_afrt())
 161
 162         return {
 163             'segments': segments,
 164             'fragments': fragments,
 165             'live': live,
 166         }
 167
 168     def read_bootstrap_info(self):
 169         total_size, box_type, box_data = self.read_box_info()
 170         assert box_type == b'abst'
 171         return FlvReader(box_data).read_abst()
 172
 173
 174 def read_bootstrap_info(bootstrap_bytes):
 175     return FlvReader(bootstrap_bytes).read_bootstrap_info()
 176
 177
 178 def build_fragments_list(boot_info):
 179     """ Return a list of (segment, fragment) for each fragment in the video """
 180     res = []
 181     segment_run_table = boot_info['segments'][0]
 182     fragment_run_entry_table = boot_info['fragments'][0]['fragments']
 183     first_frag_number = fragment_run_entry_table[0]['first']
 184     fragments_counter = itertools.count(first_frag_number)
 185     for segment, fragments_count in segment_run_table['segment_run']:
 186         for _ in range(fragments_count):
 187             res.append((segment, next(fragments_counter)))
 188
 189     if boot_info['live']:
 190         res = res[-2:]
 191
 192     return res
 193
 194
 195 def write_unsigned_int(stream, val):
 196     stream.write(struct_pack('!I', val))
 197
 198
 199 def write_unsigned_int_24(stream, val):
 200     stream.write(struct_pack('!I', val)[1:])
 201
 202
 203 def write_flv_header(stream):
 204     """Writes the FLV header to stream"""
 205     # FLV header
 206     stream.write(b'FLV\x01')
 207     stream.write(b'\x05')
 208     stream.write(b'\x00\x00\x00\x09')
 209     stream.write(b'\x00\x00\x00\x00')
 210
 211
 212 def write_metadata_tag(stream, metadata):
 213     """Writes optional metadata tag to stream"""
 214     SCRIPT_TAG = b'\x12'
 215     FLV_TAG_HEADER_LEN = 11
 216
 217     if metadata:
 218         stream.write(SCRIPT_TAG)
 219         write_unsigned_int_24(stream, len(metadata))
 220         stream.write(b'\x00\x00\x00\x00\x00\x00\x00')
 221         stream.write(metadata)
 222         write_unsigned_int(stream, FLV_TAG_HEADER_LEN + len(metadata))
 223
 224
 225 def _add_ns(prop):
 226     return '{http://ns.adobe.com/f4m/1.0}%s' % prop
 227
 228
 229 class F4mFD(FragmentFD):
 230     """
 231     A downloader for f4m manifests or AdobeHDS.
 232     """
 233
 234     FD_NAME = 'f4m'
 235
 236     def _get_unencrypted_media(self, doc):
 237         media = doc.findall(_add_ns('media'))
 238         if not media:
 239             self.report_error('No media found')
 240         for e in (doc.findall(_add_ns('drmAdditionalHeader')) +
 241                   doc.findall(_add_ns('drmAdditionalHeaderSet'))):
 242             # If id attribute is missing it's valid for all media nodes
 243             # without drmAdditionalHeaderId or drmAdditionalHeaderSetId attribute
 244             if 'id' not in e.attrib:
 245                 self.report_error('Missing ID in f4m DRM')
 246         media = list(filter(lambda e: 'drmAdditionalHeaderId' not in e.attrib and
 247                                       'drmAdditionalHeaderSetId' not in e.attrib,
 248                             media))
 249         if not media:
 250             self.report_error('Unsupported DRM')
 251         return media
 252
 253     def _get_bootstrap_from_url(self, bootstrap_url):
 254         bootstrap = self.ydl.urlopen(bootstrap_url).read()
 255         return read_bootstrap_info(bootstrap)
 256
 257     def _update_live_fragments(self, bootstrap_url, latest_fragment):
 258         fragments_list = []
 259         retries = 30
 260         while (not fragments_list) and (retries > 0):
 261             boot_info = self._get_bootstrap_from_url(bootstrap_url)
 262             fragments_list = build_fragments_list(boot_info)
 263             fragments_list = [f for f in fragments_list if f[1] > latest_fragment]
 264             if not fragments_list:
 265                 # Retry after a while
 266                 time.sleep(5.0)
 267                 retries -= 1
 268
 269         if not fragments_list:
 270             self.report_error('Failed to update fragments')
 271
 272         return fragments_list
 273
 274     def _parse_bootstrap_node(self, node, base_url):
 275         if node.text is None:
 276             bootstrap_url = compat_urlparse.urljoin(
 277                 base_url, node.attrib['url'])
 278             boot_info = self._get_bootstrap_from_url(bootstrap_url)
 279         else:
 280             bootstrap_url = None
 281             bootstrap = base64.b64decode(node.text.encode('ascii'))
 282             boot_info = read_bootstrap_info(bootstrap)
 283         return (boot_info, bootstrap_url)
 284
 285     def real_download(self, filename, info_dict):
 286         man_url = info_dict['url']
 287         requested_bitrate = info_dict.get('tbr')
 288         self.to_screen('[%s] Downloading f4m manifest' % self.FD_NAME)
 289         urlh = self.ydl.urlopen(man_url)
 290         man_url = urlh.geturl()
 291         manifest = urlh.read()
 292
 293         doc = compat_etree_fromstring(manifest)
 294         formats = [(int(f.attrib.get('bitrate', -1)), f)
 295                    for f in self._get_unencrypted_media(doc)]
 296         if requested_bitrate is None:
 297             # get the best format
 298             formats = sorted(formats, key=lambda f: f[0])
 299             rate, media = formats[-1]
 300         else:
 301             rate, media = list(filter(
 302                 lambda f: int(f[0]) == requested_bitrate, formats))[0]
 303
 304         base_url = compat_urlparse.urljoin(man_url, media.attrib['url'])
 305         bootstrap_node = doc.find(_add_ns('bootstrapInfo'))
 306         boot_info, bootstrap_url = self._parse_bootstrap_node(bootstrap_node, base_url)
 307         live = boot_info['live']
 308         metadata_node = media.find(_add_ns('metadata'))
 309         if metadata_node is not None:
 310             metadata = base64.b64decode(metadata_node.text.encode('ascii'))
 311         else:
 312             metadata = None
 313
 314         fragments_list = build_fragments_list(boot_info)
 315         if self.params.get('test', False):
 316             # We only download the first fragment
 317             fragments_list = fragments_list[:1]
 318         total_frags = len(fragments_list)
 319         # For some akamai manifests we'll need to add a query to the fragment url
 320         akamai_pv = xpath_text(doc, _add_ns('pv-2.0'))
 321
 322         ctx = {
 323             'filename': filename,
 324             'total_frags': total_frags,
 325         }
 326
 327         self._prepare_frag_download(ctx)
 328
 329         dest_stream = ctx['dest_stream']
 330
 331         write_flv_header(dest_stream)
 332         if not live:
 333             write_metadata_tag(dest_stream, metadata)
 334
 335         base_url_parsed = compat_urllib_parse_urlparse(base_url)
 336
 337         self._start_frag_download(ctx)
 338
 339         frags_filenames = []
 340         while fragments_list:
 341             seg_i, frag_i = fragments_list.pop(0)
 342             name = 'Seg%d-Frag%d' % (seg_i, frag_i)
 343             query = []
 344             if base_url_parsed.query:
 345                 query.append(base_url_parsed.query)
 346             if akamai_pv:
 347                 query.append(akamai_pv.strip(';'))
 348             if info_dict.get('extra_param_to_segment_url'):
 349                 query.append(info_dict['extra_param_to_segment_url'])
 350             url_parsed = base_url_parsed._replace(path=base_url_parsed.path + name, query='&'.join(query))
 351             frag_filename = '%s-%s' % (ctx['tmpfilename'], name)
 352             try:
 353                 success = ctx['dl'].download(frag_filename, {'url': url_parsed.geturl()})
 354                 if not success:
 355                     return False
 356                 (down, frag_sanitized) = sanitize_open(frag_filename, 'rb')
 357                 down_data = down.read()
 358                 down.close()
 359                 reader = FlvReader(down_data)
 360                 while True:
 361                     _, box_type, box_data = reader.read_box_info()
 362                     if box_type == b'mdat':
 363                         dest_stream.write(box_data)
 364                         break
 365                 if live:
 366                     os.remove(encodeFilename(frag_sanitized))
 367                 else:
 368                     frags_filenames.append(frag_sanitized)
 369             except (compat_urllib_error.HTTPError, ) as err:
 370                 if live and (err.code == 404 or err.code == 410):
 371                     # We didn't keep up with the live window. Continue
 372                     # with the next available fragment.
 373                     msg = 'Fragment %d unavailable' % frag_i
 374                     self.report_warning(msg)
 375                     fragments_list = []
 376                 else:
 377                     raise
 378
 379             if not fragments_list and live and bootstrap_url:
 380                 fragments_list = self._update_live_fragments(bootstrap_url, frag_i)
 381                 total_frags += len(fragments_list)
 382                 if fragments_list and (fragments_list[0][1] > frag_i + 1):
 383                     msg = 'Missed %d fragments' % (fragments_list[0][1] - (frag_i + 1))
 384                     self.report_warning(msg)
 385
 386         self._finish_frag_download(ctx)
 387
 388         for frag_file in frags_filenames:
 389             os.remove(encodeFilename(frag_file))
 390
 391         return True