Weird Cam Disconnect Issue - Seemingly Linked to OpenALPR Processing?


Per the title, set up OpenALPR monitoring a sub stream from a Dahua cam. License plate pickup is generally good however I’ve noticed that after a car passes by the camera appears to go offline. I see a spike in response time first (high latency in pings) before going offline. Disconnect the OpenALPR agent and don’t see this issue. I’m going to move to a different sub stream and see if that helps but wondered if anyone else had seen this issue ?



I haven’t seen this behavior before. If you’re watching the camera with another player (e.g., VLC) does the other stream drop as well?

What version of the software are you using, and is this Windows or Linux?


Hey @matt thanks for the reply. See this continually and only when the cam is attached to OpenALPR. Running this on a Mac in Docker. If I have the live stream up for the cam (use web GUI or SmartPSS etc) then cam stream goes black and spins (like its looking for the cam feed) when a car goes by. Again this seems processing related. Once I leave it 10 seconds or so, see the LPR data passed to OpenALPR then the cam feed returns and has no issues at all. Mac version can be High Sierra or Mojave. Docker is latest version (31259) and all FW is up to date on the cams.

Any thoughts on this ?

Also an additional question. I like the fact you allow the correction of a plate BUT a) why doesn’t this then reflect in the Dashboard, b) why doesn’t the algorithm seemingly learn from the correct and c) why don’t you allow the correct of the vehicle type/color etc (any plans for this in the future) ?



@matt just wondered if you had any thoughts / ideas for this issue as I am still seeing this daily ?



I would try the following:

  1. If this is an RTSP stream, Edit the /etc/openalpr/stream.d/[cameraname].conf file and add or edit this setting:
    gstreamer_format = rtsph264

  2. Try the latest software beta. I’m not sure if this will be any different, but there were some changes to the video retrieval code:
    docker pull openalpr/commercial-agent:beta-2.6.103