opencv 推rtsp流，OpenCV Error: Unspecified error (GStreamer: unable to start pipe

[b0b119]

在Linux系统中，使用opencv 推rtsp流，调用gstreamer插件如下：
VideoCaputre vcap;
try {
vcap.open("rtspsrc location=%s latency=0 ! rtph264depay ! h264parse ! mppvideodec ! autovideoconvert ! appsink", CAP_GSTREAMER);
}
catch (cv::Exception &e)
{
const char* err_msg = e.what();
cout << "抛出异常" << err_msg << endl;

// ... ...
}

报错如下：
OpenCV Error: Unspecified error (GStreamer: unable to start pipeline

) in cvCaptureFromCAM_GStreamer, file /opencv-3.4.0/modules/videoio/src/cap_gstreamer.cpp, line 890

VIDEOIO(cvCreateCapture_GStreamer (CV_CAP_GSTREAMER_FILE, filename)): raised OpenCV exception:

​/opencv-3.4.0/modules/videoio/src/cap_gstreamer.cpp:890: error: (-2) GStreamer: unable to start pipeline

in function cvCaptureFromCAM_GStreamer

opencv 抛出的异常未捕获到，导致程序崩溃，我知道报错的原因，现在只需要能不让程序崩溃就行，请问有没有处理过的大佬，非常感谢！