Attempt to open stream from *url*.

        Exits with '-1' (using self.exit()) in case of error, including
        an error msg.

def open(self, url, quality):
        """Attempt to open stream from *url*.

        Exits with '-1' (using self.exit()) in case of error, including
        an error msg.
        """

        self.original_url = url
        try:
            self.livestreamer = Livestreamer()
            self._load_config()
            streams = self.livestreamer.streams(url)
        except NoPluginError:
            self.exit("Livestreamer is unable to handle the URL '{}'".
                      format(url))
        except PluginError as err:
            self.exit("Plugin error: {}".format(err))

        if quality not in streams:
            print("Unable to find '{}' stream on URL '{}'"
                  .format(quality, url), file=sys.stderr)
            self.exit("List of available streams: {}".
                      format(sorted(streams.keys())))

        self.stream = streams[quality]
        try:
            self.fd = self.stream.open()
        except StreamError as err:
            self.exit("Failed to open stream: {}".format(err))