Common reasons for jerky videos: Network issues

A common problem which we get plenty of support calls for but is very rarely ever a problem to do with the VMS software or hardware –  is jerky (not smooth) video! Mirasys spends huge amounts of time testing and re-testing to ensure that video can be displayed to the user as smoothly as possible.  However, video display relies on a number of factors to be correctly configured – if any of these are incorrect you will face viewing problems.

Let’s start by looking at the network.

There are a number of factors relating to the network that can cause jerky video:

    • Are all connections relating to recorders and viewing stations plugged into a 1 Gigabit port or higher?  For a small system it is fine to plug a single camera into a 100 Mb port. However if there are several cameras in your system, we recommend using a Gigabit connection so not to overload the network or your video will be jerky. Not all connections are gigabit by default, you should check this.
    • Remember a network port is being used inbound and outbound.  If you are recording 500 Mbits/s of data and you want to view it – that will never work in a single Gigabit Ethernet connection.  Even 250 Mbits/s in both directions will result in problems on the Gigabit best network adapter.
    • Have you configured all you network setting correctly – a simple typo can result in weird behaviour if not a complete loss of video.  Check the Subnet Masks match and that your Gateway and DNS are correctly configured.  In theory you only need a Gateway if you are bridging 2 networks but (and we don’t know why this is) some cameras seem not to work if they do not have a Gateway address – so what do you use?  If you don’t have a real Gateway often using the recorder as a Gateway address can work.  In other cases a poorly configured Gateway can cause even more problems.
    • Check the physical connections – sometimes something as simple as a faulty cable can cause video skipping.  Always use high-quality cabling and ensure that your cabling meets the requirements of your equipment. Pick a wiring standard (568-A or 568-B). Also check the RJ45 termination: poor termination can result in POE or transmission problems. A good cable tester can also save you hours of valuable time.

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