class_docstr: Compute ZCR features respectively，and concate them. Return
  a tensor with shape (1, num_frames).
code: def __init__(self, config: dict):
      super().__init__(config)
  
file_path: delta/delta/data/frontend/zcr.py
imports: import delta.compat
  from core.ops import py_x_ops
  from delta.utils.hparam import HParams
  from delta.data.frontend.base_frontend import BaseFrontend
label_desc: Use image node_id 1 to create a new Zcr object from inherited base classes: BaseFrontend with example: obj = Zcr(config)