Some Network cameras have CVBS analog video output port to be seen through a portable monitor. It is utilized for making image more focused and setting view angle. When the camra operates in IDIS protocol, Video format between NTSC and PAL is selectable in Setup > Video > Camera > Miscellaneous > .

In case of WDR camera,

There is a condition to output the analog signal. CVBS analog video signal might not be generated from the camera. It’s limitation of SoC chip on WDR camera.

If 4th stream is not set (only 3 streams is operating), CVBS will perform well. In DirectIP NVR, if the custom field for recording is not set, CVBS will be outputted.