Testing IP Camera LatencyBy John Honovich, Published Sep 26, 2014, 12:00am EDT
How much does latency impact IP cameras?
We tested a number of combinations, like so:
In this report, we break down:
- Average latency metrics in our test
- Key drivers of latency
- Variations in latency across different systems
- Variations in latency between local and hosted video
No Single Latency Number / Metric
Our test results underscore that it is meaningless and dangerous to cite latency for individual cameras or VMSes. Latency is clearly a product of the end to end system and can be significantly impacted by limitations or issues in any given part of that system. For instance, a camera could be 'low latency' by itself but when connected to a certain network or recorder or client machine, latency could increase dramatically.
In this report, we do share measurements from our scenarios. However, keep in mind that your numbers may vary depending on your setup.
Here are the key findings from the test:
- In a simple, lightly loaded local system, latency from IP camera to VMS typically were 300 - 400ms.
- Load was the biggest factor in spiking latency numbers.
- For examples, cameras with many streams requested caused latency to increase significantly.
- Certain camera / VMS combinations may cause issues.
- Hosted video cameras latency (Dropcam) was far greater than local systems, at 2-3 seconds.
- Again, remember, one's setup and the load on each component, can significantly drive latency.
Variances of Latency
One interesting phenomenon we found was that variations in latency occurred on some combinations of cameras and VMSes but not others. For instance, a Hikvision camera connected to Milestone had periodic spikes of latency, while the same with Exacq did not. See this video:
Load and Latency
In this video, we show the impact of opening many simultaneous streams from a camera and the resulting spike in latency:
How badly a camera will be impacted depends on both the resources available on the camera and the demands on the camera (analytics, multiple streams, etc.). As such, this is not simple to forecast.
Hosted Video Latency
Finally, hosted video sent to the cloud and then retrieved from it, had significant latency issues. This screencapture below shows one test run and the 2+ second latency observed.
Of course, Dropcam's latency can vary, depending on factors including upstream bandwidth from the camera's site, load on Dropcam's service, congestion on connection to client, etc.
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