implemented even hotter fix, after second breaking change in a day

coub-dl.py

@@ -50,6 +50,7 @@ class coub_dl:
         self.download_audio_stream()
         self.download_video_stream()
         self.read_extensions()
+        self.fix_video_stream()
 
         # get stream lengths via ffprobe
         audioLen = coub_dl.get_length(self._files_dict[Stream.AUDIO])
@@ -89,14 +90,9 @@ class coub_dl:
 
     @call_verbose(before_message='Downloading video stream... ')
     def download_video_stream(self):
-        url = get_output(('youtube-dl',
-                          '--get-url', self._url))
-
-        url = url.replace('muted_', '')
-
         call(('youtube-dl', '--ignore-config',
               '--output', '{}.%(ext)s'.format(self._files_dict[Stream.VIDEO]),
-              url),
+              self._url),
              stdout=DEVNULL, stderr=DEVNULL)
 
 
@@ -108,6 +104,13 @@ class coub_dl:
                     self._files_dict[filename] = fullname
 
 
+    def fix_video_stream(self):
+        """ magic fix for videos served by coub. see https://github.com/rg3/youtube-dl/issues/13754 """
+        with open(self._files_dict[Stream.VIDEO], 'r+b') as f:
+            f.seek(0)
+            f.write(bytes(2))
+
+
     @call_verbose(before_message='Looping shorter stream... ')
     def loop_shorter_stream(self, shorter, shorter_file, loop_fraction):
         # prepare last fractional loop