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3.13 Artifacts or a Blank Screen Occurs on Live Video Images

Publication Date:  2015-06-23 Views:  32 Downloads:  0
Issue Description
When you view live video on the Live Feed tab page of the eSpace IVS C/S client, artifacts or a blank screen occurs on the live video images.
Handling Process
Step 1 Log in to the server where the camera is connected as the root user.
Step 2 Run the tcpdump -i ethx host deviceIP -s0 -vv -w /home/devtodcg.pcap command.

 ethx indicates the service network adapter in use, for example, eth0. If you do not know the specific network adapter, you can enter any, indicating that packets of all network adapters are captured. This will result in a too large size of captured packets.
 host deviceIP indicates that only communication packets between the server and the camera whose IP address is the value of deviceIP are captured.
 /home/devtodcg.pcap indicates the directory where captured packets are stored.
Step 3 Log in to the eSpace IVS C/S client, enable live video from the camera. About 2 minutes later, press Ctrl+C to stop capturing packets.
Step 4 Go to the /home directory and obtain the captured packet devtodcg.pcap.

To minimize disk usage, run the rm /home/devtodcg.pcap command to delete devtodcg.pcap from the server after obtaining it.
Step 5 Use Wireshark to open devtodcg.pcap and check whether the size of the RTP packet exceeds 1500 bytes, as shown in Figure 3-8.

Obtain the Wireshark installation package from http://www.wireshark.org/.
Figure 3-9 RTP packet sent by the camera to the eSpace IVS platform


 If no, contact Huawei technical support engineers.
 If yes, contact the device vendor to change the RTP packet size and go to the next step.
Step 6 Check whether the fault is rectified.
If the fault is rectified, no further action is required. If the fault persists, contact Huawei technical support engineers.
Root Cause
The size of RTP packets sent by the camera exceeds the size of the buffer where the eSpace IVS platform receives RTP packets.

 The RTP packet is a standard data packet format for uploading audio and video over the Internet.
 The size of the buffer where the eSpace IVS platform receives RTP packets is 1500 bytes. If the size of RTP packets sent to the eSpace IVS platform exceeds 1500 bytes, the RTP packets will be truncated, which results in data loss.
 If the lost data is media key frames, a blank screen occurs on the live video images.
 If the lost data is non-media key frames, artifacts occur on the live video images.

END