To come back to your RTSP stream on VLC player. The newer NVX boxes produce two different streams. One is the full bandwidth encrypted one that goes to the NVX decoder HDMI output. The second stream Crestron calls "image preview" and refreshes every second or two. This "image preview" stream can be accessed from VLC player or even a Crestron Touchpanel.? For full security it can also be turned off in the web interface of the encoder/decoder.
The statement that NVX doesn't work on Cisco is just false.