带有RTSP流的opencv

Question

我有一个RTSP流，我在VLC上测试过，它工作正常。现在我有了这个脚本，它试图分析流中的帧

import cv2
import os

os.environ["OPENCV_FFMPEG_CAPTURE_OPTIONS"] = "rtsp_transport;udp"
vcap = cv2.VideoCapture("rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov", cv2.CAP_FFMPEG)
if vcap.isOpened():
    while(1):
        ret, frame = vcap.read()
        print((ret, frame.size))
        cv2.imshow('VIDEO', frame)
        cv2.waitKey(0)
        cv2.destroyAllWindows()
else:
    print('video cap is not opened')

它可以连接到流，但输出只是黑屏。以下是其他帖子建议的opencv构建信息：

  Video I/O:
    DC1394:                      NO
    FFMPEG:                      YES
      avcodec:                   YES (58.54.100)
      avformat:                  YES (58.29.100)
      avutil:                    YES (56.31.100)
      swscale:                   YES (5.5.100)
      avresample:                YES (4.0.0)
    GStreamer:                   NO
    AVFoundation:                YES

环境是MacOS、python3.6和opencv4.5.1