There are four main scenarios when a Dahua camera shows a black screen and is unable to preview, even when it is online:
Scenario 1:
Black screen in both single screen and multi-screen preview.
Cause Analysis:
This is usually caused by the NVR not supporting the camera’s encoding format. The most common situation is that the camera is using H.265 encoding, while the NVR only supports H.264.
Solution:
Access the camera via the web interface, go to Settings > Camera Settings > Video, and change both the main stream and sub-stream encoding mode to H.264.
Scenario 2:
Single screen preview is normal, but the fixed channel is black in multi-screen preview.
Cause Analysis:
The sub-stream of the corresponding channel camera does not have video enabled.
Solution:
Access the camera via the web interface, go to Settings > Camera Settings > Video, and enable the sub-stream.
Scenario 3:
Single screen preview is normal, but different channels randomly show a black screen in multi-screen preview.
Cause Analysis:
There is insufficient performance at some point in the network transmission.
Solution:
Reduce the camera’s bit rate or identify the network bottleneck by analyzing the camera’s bit rate, and replace the underperforming components (e.g., switch, network cables) with higher-performance alternatives.
Scenario 4:
Preview window shows “Decoder Performance Exceeded”.
Cause Analysis:
The camera’s resolution exceeds the decoding capability of the NVR.
Solution:
Lower the camera’s resolution, or replace the NVR with one that has higher decoding capabilities.