实现基于海康前端NVR设备的录像文件查询、取流播放下载等功能；界面友好；适合基于海康设备的二次开发人员使用，执行需海康相关库文件；-Kang-based front-end NVR device video file queries, taking streaming download functions friendly interface suitable for secondary development based on the use of equipment personnel