import cv2
import subprocess

rtsp = "rtsp://admin:2020@uestc@192.168.30.83:554/h264"
out_rtsp = 'rtsp://localhost:5001/test'

# 读取视频并获取属性
cap = cv2.VideoCapture(rtsp)
size = (int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)), int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT)))
sizeStr = str(size[0]) + 'x' + str(size[1])
fps = cap.get(cv2.CAP_PROP_FPS)
command = ['ffmpeg',
           '-y', '-an',
           '-f', 'rawvideo',
           '-vcodec', 'rawvideo',
           '-pix_fmt', 'bgr24',
           '-s', sizeStr,
           '-r', str(fps),
           '-i', '-',
           '-c:v', 'libx264',
           '-pix_fmt', 'yuv420p',
           '-preset', 'ultrafast',
           '-f', 'rtsp',
           out_rtsp]

pipe = subprocess.Popen(command, shell=False, stdin=subprocess.PIPE)

while cap.isOpened():
    success, frame = cap.read()
    if success:
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
        pipe.stdin.write(frame.tostring())

cap.release()
pipe.terminate()