Measuring Video Latency

Issue:

The customer is stating video / audio is delayed by a few seconds.

Resolution:

Prerequisites:

• Wireshark
• VLC
• Laptop direct connected to the camera with a PoE injector.

1. Install Wireshark and VLC on your laptop.
2. Launch Wireshark, select the appropriate Ethernet interface and in the capture filter type "host x.x.x.x" where x.x.x.x is the IP Address of the camera > Start Capturing Packets.
   
   
   
   
3. Launch VLC, select Media > Open Network Stream > type in the RTSP URL of the camera (see below articles) > click Play.
   • How to connect to RTSP streams on Arecont cameras
   • How to connect to RTSP streams on Contera cameras
   • Example: rtsp://10.6.0.85/stream1
4. Let it run for 30 - 60 seconds then click Stop.
5. Close VLC.
6. In the display filter field, type rtp then click Enter.
   
   
   
   
7. Click on the first packet displayed. In the packet information click User Datagram Protocol > Timestamps.
   
   
   
   
8. Right click on [Time since first frame: 0.0000000 seconds] > Apply as Column.
9. Right click on [Time since previous frame: 0.0000000 seconds] > Apply as Column.
10. Your column list should look similar to the below.
    
    
    
    Note: Should they choose to, they can scroll through / sort this list to find the packet with the highest delta.
    
    
11. Click Telephony > RTP > RTP Streams.
    
    
    
    
12. Click the stream then click Analyze.
    
    
    
    
13. The largest delta was 80.18 ms at packet number 43091.
    
    
    
    
14. There is a graph option which will display the results for easier viewing purposes. This shows the average latency when direct connected to the camera.
    
    
    
    
15. Repeat these steps at each network segment. This will help identify where in the network infrastructure the latency is being induced.