Hi,
You may save the h264 stream to a file and run pipeline like:
filesrc ! h264parse ! nvv4l2decoder ! nvvidconv ! video/x-raw,format=BGRx ! videoconvert ! video/x-raw,format=BGR ! queue ! appsink
There is no sample with appsrc. A sample close to this use-case is with rtspsrc. You may refer to
Doesn't work nvv4l2decoder for decoding RTSP in gstreamer + opencv - #3 by DaneLLL