Issue with video analytics input streams

Modified on Wed, 19 Aug 2020 at 10:02 PM

You probably have heard about it, but a problem relating to video analytics input stream has been detected few days ago (Siemens Hamburg).

This problem impacts the performance of our systems and occurs only if the video analytic input stream is set to 5fps.


First analysis from R&D team showed that, for some unknown reasons, the stream delivered by the camera can be 5fps on average, but with variable intervals between frames instead of a consistent 200ms.

Due to that, our analytics cannot operate properly.


How to detect it ? The issue is pretty difficult to detect …

  • Visual verification: the stream is not fluid, with a constant flow (must be checked with VLC)
  • Vehicle speed : the speed  is not coherent. For example, the average measured speed in a 50Km/h tunnel is 70Km/h.
  • Alarms based on vehicle speed : all alarms based on speed  will be affected : congestion, slow vehicle


Workaround solutions :

  • As the problem occurs only with 5fps streams, you can adjust the input frame rate above 5fs (6fps will work ; up to 10fps will work but CPU must be checked).
  • Adjust the buffering : increasing the buffering parameter will help to get fluid decoded images.

    • Typically, for a 5fps input stream, a 3-to-5 seconds buffering should help to get a proper stream.


What’s next ?

  • Even if we have probably identified the problem, we still don’t know its root cause…
  • R&D team is still investigating and also working on a diagnostic tool to ease the problem detection.
  • We will try to organize a webex meeting PS+DEV as soon as R&D team will know more about the root cause.



This problem does not impact systems based on Smartcams.

It impacts solutions based on Citilog Media with analyzers.


If you think one of your clients could be impacted, check the analytic stream configuration. If you can, increase the input frame rate to 6fps or add a 3 to 5 secondes buffering. INFORM US (please) !


If you have any doubt, contact us (R&D or PM team).

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