empty tensor
netInput = np.empty([0, 4])
netTarget = np.empty([0, 4])
inputWidth = 2
for step in range(data.shape.as_list()[-2]-frames_width-1):
netInput = tf.concat([netInput, data[0, step:step + frames_width, :]], -2)
target = tf.concat([target, data[0, step + frames_width + 1:step + frames_width + 2, :]], -2)