-            return '%s/%s' % (base_url, target_url)
-
-        with open(tmpfilename, 'wb') as outf:
-            append_url_to_file(
-                outf, combine_url(base_url, info_dict['initialization_url']),
-                'initialization segment')
-            for i, segment_url in enumerate(segment_urls):
-                segment_len = append_url_to_file(
-                    outf, combine_url(base_url, segment_url),
-                    'segment %d / %d' % (i + 1, len(segment_urls)),
-                    remaining_bytes)
-                byte_counter += segment_len
-                if remaining_bytes is not None:
-                    remaining_bytes -= segment_len
-                    if remaining_bytes <= 0:
-                        break
-
-        self.try_rename(tmpfilename, filename)
-
-        self._hook_progress({
-            'downloaded_bytes': byte_counter,
-            'total_bytes': byte_counter,
-            'filename': filename,
-            'status': 'finished',
-        })
+            return '%s%s%s' % (base_url, '' if base_url.endswith('/') else '/', target_url)
+
+        segments_filenames = []
+
+        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
+
+        if initialization_url:
+            append_url_to_file(initialization_url, ctx['tmpfilename'], 'Init')
+        for i, segment_url in enumerate(segment_urls):
+            append_url_to_file(segment_url, ctx['tmpfilename'], 'Seg%d' % i)
+
+        self._finish_frag_download(ctx)
+
+        for segment_file in segments_filenames:
+            os.remove(encodeFilename(segment_file))