code: def download_mp4(from_idx, to_idx, _params):
      
      succ = set()
      fail = set()
      for idx in range(from_idx, to_idx):
          name = 's' + str(idx)
          save_folder = '{src_path}/{nm}'.format(src_path=_params['src_path'], nm=name)
          if idx == 0 or os.path.isdir(save_folder):
              continue
          script = "http://spandh.dcs.shef.ac.uk/gridcorpus/{nm}/video/{nm}.mpg_vcd.zip".format( \
                      nm=name)
          down_sc = 'cd {src_path} && curl {script} --output {nm}.mpg_vcd.zip && \
                      unzip {nm}.mpg_vcd.zip'.format(script=script,
                                                     nm=name,
                                                     src_path=_params['src_path'])
          try:
              print(down_sc)
              os.system(down_sc)
              succ.add(idx)
          except OSError as error:
              print(error)
              fail.add(idx)
      return (succ, fail)
docs: download mp4s