Gstreamer-opencv读取视频文件加速
cv::VideoCapture capVideo("filesrc location=CarsDrivingUnderBridge.mp4 ! qtdemux ! h264parse ! nvv4l2decoder ! nvvidconv ! video/x-raw, format=BGRx ! videoconvert ! video/x-raw, format=BGR ! appsink ", cv::CAP_GSTREAMER);