_ 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 from ..utils import urljoin
   6
   7
   8 class DashSegmentsFD(FragmentFD):
   9     """
  10     Download segments in a DASH manifest
  11     """
  12
  13     FD_NAME = 'dashsegments'
  14
  15     def real_download(self, filename, info_dict):
  16         fragment_base_url = info_dict.get('fragment_base_url')
  17         fragments = info_dict['fragments'][:1] if self.params.get(
  18             'test', False) else info_dict['fragments']
  19
  20         ctx = {
  21             'filename': filename,
  22             'total_frags': len(fragments),
  23         }
  24
  25         self._prepare_and_start_frag_download(ctx)
  26
  27         fragment_retries = self.params.get('fragment_retries', 0)
  28         skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)
  29
  30         frag_index = 0
  31         for i, fragment in enumerate(fragments):
  32             frag_index += 1
  33             if frag_index <= ctx['fragment_index']:
  34                 continue
  35             # In DASH, the first segment contains necessary headers to
  36             # generate a valid MP4 file, so always abort for the first segment
  37             fatal = i == 0 or not skip_unavailable_fragments
  38             count = 0
  39             while count <= fragment_retries:
  40                 try:
  41                     fragment_url = fragment.get('url')
  42                     if not fragment_url:
  43                         assert fragment_base_url
  44                         fragment_url = urljoin(fragment_base_url, fragment['path'])
  45                     success, frag_content = self._download_fragment(ctx, fragment_url, info_dict)
  46                     if not success:
  47                         return False
  48                     self._append_fragment(ctx, frag_content)
  49                     break
  50                 except compat_urllib_error.HTTPError as err:
  51                     # YouTube may often return 404 HTTP error for a fragment causing the
  52                     # whole download to fail. However if the same fragment is immediately
  53                     # retried with the same request data this usually succeeds (1-2 attemps
  54                     # is usually enough) thus allowing to download the whole file successfully.
  55                     # To be future-proof we will retry all fragments that fail with any
  56                     # HTTP error.
  57                     count += 1
  58                     if count <= fragment_retries:
  59                         self.report_retry_fragment(err, frag_index, count, fragment_retries)
  60             if count > fragment_retries:
  61                 if not fatal:
  62                     self.report_skip_fragment(frag_index)
  63                     continue
  64                 self.report_error('giving up after %s fragment retries' % fragment_retries)
  65                 return False
  66
  67         self._finish_frag_download(ctx)
  68
  69         return True