定义JPEG编码属性字典,暂不支持。
hi_venc_jpeg_attr = {"dcf_en": dcf_en, # RW; Range:[0, 1]; support dcf "mpf_cfg": hi_venc_mpf_cfg, # RW; Range:[0, 1]; config of Mpf "recv_mode": hi_venc_pic_recv_mode} # RW; Config the receive mode;