Should you encounter problems with the video call functionality of the messenger, you can run the videochat tester to try and find the cause. After running the test a form will pop up, which you can use to send us the results so we can help you interpret them.

In this post we will also provide you with additional information about what is specifically being tested and what this means. In the overview below, we have listed the same topics as used in the tester.


Under ‘Microphone’ you will find one section: ‘Audio capture’. This tests the following:

  • Whether the available microphone is able to reproduce 2 seconds of non-silent audio;
  • The RMS (Root-Mean-Square) is measured to check the maximum output of the microphone;
  • The output will be checked for audio clipping;
  • The tester will also check whether it can detect mono microphones.


Under ‘Camera’ you will see two parts: ‘Check WxH resolution’ and ‘Check supported resolutions’. The tester will check whether the camera is able to produce files and ready them for sending, based on the following tests:

  • Whether the camera is able to capture 5 seconds of video at the requested resolution;
  • Whether the frames are not frozen or muted / black;
  • How long it takes to encode frames (for sending / sharing video imagery) – both the encode time and the average framerate will be shown in the report;
  • The test will also produce a list of resolutions that appear to be supported.


Under ‘Network’ the tester will check the UDP (User Datagram Protocol) and TCP (Transmission Control Protocol).

To make sure this article is not too technical, the simplified explanation of this part of the test would be as follows: the test checks whether the protocols mentioned above are able to send data, by checking if there is a server available to process the data.


In the ‘Connectivity’ part, the tester checks whether there are no blockages when sending sending / receiving video data, based on the following:

  • The relay: the transmission of data using a connection with a so-called TURN server – Traversal Using Relays around NAT (Network Address Translation).
  • The reflexive: the transmission of data using computers connected to the internet by means of a router.
  • The host: the exchange of data between end-points with the same IP address.


To test whether data can be sent and received smoothly, the tester runs a so-called loopback call. The video bandwidth will also be tested with such a loopback call, which will also check the video performance. The RTT (roundtrip time) will also be checked, to see how long it takes to exchange data.

Do let us know if you need any further assistance with the video call functionality – running the test and sending us the results is a great first step to do so, so that we will have some useful information to start our research.