Here is a list of tested URL's for Hikvision NVR streaming URL. This will stream the IP cameras that are connected to the NVR.
Main RTSP Stream:
Channel/Camera 1 - rtsp://admin:12345@192.168.1.100/Streaming/Channels/101
Channel/Camera 2 - rtsp://admin:12345@192.168.1.100/Streaming/Channels/201
Channel/Camera X - rtsp://admin:12345@192.168.1.100/Streaming/Channels/X01
Sub RTSP Stream:
Channel/Camera 1 - rtsp://admin:12345@192.168.1.100/Streaming/Channels/102
Channel/Camera 2 - rtsp://admin:12345@192.168.1.100/Streaming/Channels/202
Channel/Camera X - rtsp://admin:12345@192.168.1.100/Streamin/Channels/X02
Remember to change the username and password as well as IP address of the NVR (in this example its 192.168.1.100) to match your setup. You can also add ?tcp to the end of the URL if you get corrupted frames. Example: rtsp://admin:12345@192.168.1.100/Streaming/Channels/102?tcp