[downloader/dash] Add fragment retry capability

YouTube may often return 404 HTTP error for a fragment causing the
whole download to fail. However if the same fragment is immediately
retried with the same request data this usually succeeds (1-2 attemps
is usually enough) thus allowing to download the whole file successfully.
So, we will retry all fragments that fail with 404 HTTP error for now.
pull/8/head
Sergey M․ 9 years ago
parent 721f26b821
commit e33baba0dd

@ -4,6 +4,7 @@ import os
import re
from .fragment import FragmentFD
from ..compat import compat_urllib_error
from ..utils import (
sanitize_open,
encodeFilename,
@ -36,20 +37,41 @@ class DashSegmentsFD(FragmentFD):
segments_filenames = []
def append_url_to_file(target_url, target_filename):
success = ctx['dl'].download(target_filename, {'url': combine_url(base_url, target_url)})
if not success:
fragment_retries = self.params.get('fragment_retries', 0)
def append_url_to_file(target_url, tmp_filename, segment_name):
target_filename = '%s-%s' % (tmp_filename, segment_name)
count = 0
while count <= fragment_retries:
try:
success = ctx['dl'].download(target_filename, {'url': combine_url(base_url, target_url)})
if not success:
return False
down, target_sanitized = sanitize_open(target_filename, 'rb')
ctx['dest_stream'].write(down.read())
down.close()
segments_filenames.append(target_sanitized)
break
except (compat_urllib_error.HTTPError, ) as err:
# YouTube may often return 404 HTTP error for a fragment causing the
# whole download to fail. However if the same fragment is immediately
# retried with the same request data this usually succeeds (1-2 attemps
# is usually enough) thus allowing to download the whole file successfully.
# So, we will retry all fragments that fail with 404 HTTP error for now.
if err.code != 404:
raise
# Retry fragment
count += 1
if count <= fragment_retries:
self.report_retry_fragment(segment_name, count, fragment_retries)
if count > fragment_retries:
self.report_error('giving up after %s fragment retries' % fragment_retries)
return False
down, target_sanitized = sanitize_open(target_filename, 'rb')
ctx['dest_stream'].write(down.read())
down.close()
segments_filenames.append(target_sanitized)
if initialization_url:
append_url_to_file(initialization_url, ctx['tmpfilename'] + '-Init')
append_url_to_file(initialization_url, ctx['tmpfilename'], 'Init')
for i, segment_url in enumerate(segment_urls):
segment_filename = '%s-Seg%d' % (ctx['tmpfilename'], i)
append_url_to_file(segment_url, segment_filename)
append_url_to_file(segment_url, ctx['tmpfilename'], 'Seg%d' % i)
self._finish_frag_download(ctx)

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