import cv2
import os
import numpy as np

VIDEO_PATH = 'Test_Video/person_video.mp4'
RESULT_PATH = 'result1.mp4'

#指定多边形的顶点坐标
polygonPoints=np.array([[410,150],[810,150],[510,300],[110,300]],dtype=np.int32)

if __name__ == '__main__':
    if not os.path.exists(VIDEO_PATH):
        print(f'视频文件不存在: {VIDEO_PATH}')
        exit()

    capture = cv2.VideoCapture(VIDEO_PATH)
    if not capture.isOpened():
        print('无法打开视频文件')
        exit()

    fps=capture.get(cv2.CAP_PROP_FPS)                         #获取帧率
    frame_width=int(capture.get(cv2.CAP_PROP_FRAME_WIDTH))    #获取宽度
    frame_height=int(capture.get(cv2.CAP_PROP_FRAME_HEIGHT))  #获取高度
    print(f'帧率:{fps},宽度:{frame_width},高度:{frame_height}')

    videoWriter=None

    while True:
        success,frame=capture.read()     #读取视频中的一帧
        if not success:
            print('无法读取帧，可能是视频结束或读取失败')
            break

        #在视频中间画一条线段
        cv2.line(frame,pt1=(0,int(frame_height/2)),pt2=(int(frame_width),int(frame_height/2)),color=(0,0,255),thickness=3)
        #画一个多边形
        cv2.polylines(frame,pts=[polygonPoints],isClosed=True,color=(0,0,255),thickness=2)

        #生成一张同样大小的空图片
        mask=np.zeros_like(frame)
        #填充多边形
        cv2.fillPoly(mask,pts=[polygonPoints],color=(0,255,255))
        #融合两张图片
        frame=cv2.addWeighted(frame,0.7,mask,0.3,0)

        #保存处理好的视频
        if videoWriter is None:
            fourcc=cv2.VideoWriter_fourcc('m','p','4','v')
            videoWriter=cv2.VideoWriter(RESULT_PATH,fourcc,fps,(int(frame_width),int(frame_height)))
        videoWriter.write(frame)

        if frame is not None:
            cv2.imshow(winname='window', mat=frame)

        #参数如果设置得太小,视频就会播放得很快
        if cv2.waitKey(1) & 0xFF == ord(' '):
            break

    print('视频播放结束')
    #释放内存资源
    capture.release()
    videoWriter.release()
    cv2.destroyAllWindows()