          _output_path = output.path + "/" + input_.name + "_%05d" + extract_ext
          _output = {_output_path: _output_opts}
          os.makedirs(output.path, exist_ok=True)
          Effmpeg.__run_ffmpeg(inputs=_input, outputs=_output)
  
      @staticmethod
      def gen_vid(input_=None, output=None, fps=None, mux_audio=False,
 
</s> remove     def extract(input_=None, output=None, fps=None, extract_ext=None,
 </s> add     def extract(input_=None, output=None, fps=None, extract_ext=None, start=None, duration=None,
        logger.debug("_input: %s, _output: %s", _input, _output)
          _output_path = output.path + "/" + input_.name + "_%05d" + extract_ext
          _output = {_output_path: _output_opts}
          os.makedirs(output.path, exist_ok=True)
        logger.debug("_input: %s, _output: %s", _input, _output)
          Effmpeg.__run_ffmpeg(inputs=_input, outputs=_output)
  
      @staticmethod
      def gen_vid(input_=None, output=None, fps=None, mux_audio=False,
keep keep add keep keep keep keep
 Fix duration for effmpeg extract 
tools/effmpeg.py