code: def output(*streams_and_filename, **kwargs):
      
      streams_and_filename = list(streams_and_filename)
      if 'filename' not in kwargs:
          if not isinstance(streams_and_filename[-1], basestring):
              raise ValueError('A filename must be provided')
          kwargs['filename'] = streams_and_filename.pop(-1)
      streams = streams_and_filename
  
      fmt = kwargs.pop('f', None)
      if fmt:
          if 'format' in kwargs:
              raise ValueError("Can't specify both `format` and `f` kwargs")
          kwargs['format'] = fmt
      return OutputNode(streams, output.__name__, kwargs=kwargs).stream()
docs: Output file URL
  
      Syntax:
          `ffmpeg.output(stream1[, stream2, stream3...], filename, **ffmpeg_args)`
  
      Any supplied keyword arguments are passed to ffmpeg verbatim (e.g.
      ``t=20``, ``f='mp4'``, ``acodec='pcm'``, ``vcodec='rawvideo'``,
      etc.).  Some keyword-arguments are handled specially, as shown below.
  
      Args:
          video_bitrate: parameter for ``-b:v``, e.g. ``video_bitrate=1000``.
          audio_bitrate: parameter for ``-b:a``, e.g. ``audio_bitrate=200``.
          format: alias for ``-f`` parameter, e.g. ``format='mp4'``
              (equivalent to ``f='mp4'``).
  
      If multiple streams are provided, they are mapped to the same
      output.
  
      To tell ffmpeg to write to stdout, use ``pipe:`` as the filename.
  
      Official documentation: `Synopsis <https://ffmpeg.org/ffmpeg.html#Synopsis>`__