Implementing rtsp streaming with audio from usb

thanks

 ./test-launch 'nvarguscamerasrc ! nvvidconv ! nvv4l2h264enc ! h264parse ! queue ! rtph264pay name=pay0 pt=96 alsasrc device="hw:2,0" ! voaacenc ! queue ! rtpmp4apay pt=97 name=pay1'
stream ready at rtsp://127.0.0.1:8554/test

worked