yt_dlp/downloader/dash.py

   1 from __future__ import unicode_literals
   2
   3 from ..downloader import _get_real_downloader
   4 from .fragment import FragmentFD
   5
   6 from ..compat import compat_urllib_error
   7 from ..utils import (
   8     DownloadError,
   9     urljoin,
  10 )
  11
  12
  13 class DashSegmentsFD(FragmentFD):
  14     """
  15     Download segments in a DASH manifest
  16     """
  17
  18     FD_NAME = 'dashsegments'
  19
  20     def real_download(self, filename, info_dict):
  21         fragment_base_url = info_dict.get('fragment_base_url')
  22         fragments = info_dict['fragments'][:1] if self.params.get(
  23             'test', False) else info_dict['fragments']
  24
  25         real_downloader = _get_real_downloader(info_dict, 'frag_urls', self.params, None)
  26
  27         ctx = {
  28             'filename': filename,
  29             'total_frags': len(fragments),
  30         }
  31
  32         if real_downloader:
  33             self._prepare_external_frag_download(ctx)
  34         else:
  35             self._prepare_and_start_frag_download(ctx)
  36
  37         fragment_retries = self.params.get('fragment_retries', 0)
  38         skip_unavailable_fragments = self.params.get('skip_unavailable_fragments', True)
  39
  40         fragment_urls = []
  41         frag_index = 0
  42         for i, fragment in enumerate(fragments):
  43             frag_index += 1
  44             if frag_index <= ctx['fragment_index']:
  45                 continue
  46             fragment_url = fragment.get('url')
  47             if not fragment_url:
  48                 assert fragment_base_url
  49                 fragment_url = urljoin(fragment_base_url, fragment['path'])
  50
  51             if real_downloader:
  52                 fragment_urls.append(fragment_url)
  53                 continue
  54
  55             # In DASH, the first segment contains necessary headers to
  56             # generate a valid MP4 file, so always abort for the first segment
  57             fatal = i == 0 or not skip_unavailable_fragments
  58             count = 0
  59             while count <= fragment_retries:
  60                 try:
  61                     success, frag_content = self._download_fragment(ctx, fragment_url, info_dict)
  62                     if not success:
  63                         return False
  64                     self._append_fragment(ctx, frag_content)
  65                     break
  66                 except compat_urllib_error.HTTPError as err:
  67                     # YouTube may often return 404 HTTP error for a fragment causing the
  68                     # whole download to fail. However if the same fragment is immediately
  69                     # retried with the same request data this usually succeeds (1-2 attempts
  70                     # is usually enough) thus allowing to download the whole file successfully.
  71                     # To be future-proof we will retry all fragments that fail with any
  72                     # HTTP error.
  73                     count += 1
  74                     if count <= fragment_retries:
  75                         self.report_retry_fragment(err, frag_index, count, fragment_retries)
  76                 except DownloadError:
  77                     # Don't retry fragment if error occurred during HTTP downloading
  78                     # itself since it has own retry settings
  79                     if not fatal:
  80                         self.report_skip_fragment(frag_index)
  81                         break
  82                     raise
  83
  84             if count > fragment_retries:
  85                 if not fatal:
  86                     self.report_skip_fragment(frag_index)
  87                     continue
  88                 self.report_error('giving up after %s fragment retries' % fragment_retries)
  89                 return False
  90
  91         if real_downloader:
  92             info_copy = info_dict.copy()
  93             info_copy['url_list'] = fragment_urls
  94             fd = real_downloader(self.ydl, self.params)
  95             # TODO: Make progress updates work without hooking twice
  96             # for ph in self._progress_hooks:
  97             #     fd.add_progress_hook(ph)
  98             success = fd.real_download(filename, info_copy)
  99             if not success:
 100                 return False
 101         else:
 102             self._finish_frag_download(ctx)
 103         return True