_ Git - youtube-dl/blob - youtube_dl/downloader/dash.py

   1 from __future__ import unicode_literals
   2
   3 from .fragment import FragmentFD
   4 from ..compat import compat_urllib_error
   5
   6
   7 class DashSegmentsFD(FragmentFD):
   8     """
   9     Download segments in a DASH manifest
  10     """
  11
  12     FD_NAME = 'dashsegments'
  13
  14     def real_download(self, filename, info_dict):
  15         segments = info_dict['fragments'][:1] if self.params.get(
  16             'test', False) else info_dict['fragments']
  17
  18         ctx = {
  19             'filename': filename,
  20             'total_frags': len(segments),
  21         }
  22
  23         self._prepare_and_start_frag_download(ctx)
  24
  25         fragment_retries = self.params.get('fragment_retries', 0)
  26         skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)
  27
  28         frag_index = 0
  29         for i, segment in enumerate(segments):
  30             frag_index += 1
  31             if frag_index <= ctx['frag_index']:
  32                 continue
  33             # In DASH, the first segment contains necessary headers to
  34             # generate a valid MP4 file, so always abort for the first segment
  35             fatal = i == 0 or not skip_unavailable_fragments
  36             count = 0
  37             while count <= fragment_retries:
  38                 try:
  39                     success, frag_content = self._download_fragment(ctx, segment['url'], info_dict)
  40                     if not success:
  41                         return False
  42                     self._append_fragment(ctx, frag_content)
  43                     break
  44                 except compat_urllib_error.HTTPError as err:
  45                     # YouTube may often return 404 HTTP error for a fragment causing the
  46                     # whole download to fail. However if the same fragment is immediately
  47                     # retried with the same request data this usually succeeds (1-2 attemps
  48                     # is usually enough) thus allowing to download the whole file successfully.
  49                     # To be future-proof we will retry all fragments that fail with any
  50                     # HTTP error.
  51                     count += 1
  52                     if count <= fragment_retries:
  53                         self.report_retry_fragment(err, frag_index, count, fragment_retries)
  54             if count > fragment_retries:
  55                 if not fatal:
  56                     self.report_skip_fragment(frag_index)
  57                     continue
  58                 self.report_error('giving up after %s fragment retries' % fragment_retries)
  59                 return False
  60
  61         self._finish_frag_download(ctx)
  62
  63         return True