Video Freezing, Cutting Out, Or Unstable

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Category: Online Lesson A/V

Most video issues experienced on Blink Lesson will occur on any other video conferencing system, because they are related to the Internet connection, local network, or device.

This test will run diagnostics on your connection to try and predict video call quality. Please remember, this is only a test of your connection. The connection of the person you are meeting with is equally important.Begin Test

What Affects Video Call Quality?

Reasons why video might freeze, stop, or cuts in and out fall into two categories: Low bandwidth or network congestion/interference.


Bandwidth is only one factor which affects quality. It is the maximum amount of data which can be transmitted over a certain period from one device to another. Use a speed test website. The results will provide "Download Mbps" (megabytes per second) and "Upload Mbps". Your bandwidth quota is shared by all the devices using your internet connection.

Download vs. Upload

Your internet service provide (ISP) provides a maximum "Download" and "Upload" quota. "Download" refers to data that is sent to your computer/phone from a server or another person you are having a video call with. "Upload" is data which is sent from your device. Thus, you download a movie from Netflix, but when you search for a Netflix movie, you are uploading the search text. During a video call, you are downloading the other person's video and simultaneously uploading video from your camera.

How Much Bandwidth You Actually Get

First: Your ISP advertises the maximum amount of download bandwidth they will allow your connection to have at any one time ("Up to"). Your real-life bandwidth is typically 2-3 times less than the maximum.

Second: You receive much less upload speed but this is needed for video calls. ISPs provide less upload capacity because most of your internet needs are for downloading.

Because IPSs provide significantly less "upload" capacity, sometimes a connection is sufficient for watching Netflix (downloading), but a video call is difficult or impossible. This is because, during a video call, you are "uploading" video from your camera.


Network Congestion or Interference

Network congestion interference issues can be caused by your ISP or your local network (wired or Wifi).

Poor Latency

Latency (ping rate) is a measure of the of time (milliseconds) it takes to send information from one point to another. If we use the analogy of a pipe; bandwidth has to do with how wide it is, where latency has to do with how fast things move through it. You want low latency.

Poor latency particularity affects live video calls. Look at it this way: If you only use your connection to download content, even movies, latency is less important because you are retrieving data that is simply stored on a server. It will take longer to "buffer" the content but eventually it will arrive. With live video calls, the data (audio/video) is being created in real-time and thus cannot be buffered. Poor latency can cause a live video not to be able to keep up or shut down all together.

You can test your latency here. Please note: The connection your ISP provides is usually the cause of poor latency, but your local network and device can also play a role.


Jitter refers to the fluctuation of latency over time. Say you test your latency right now and are receiving a 45ms rate, but a few seconds latter it shoots up to 250ms. The change will have a big impact on the stability of your video call. As with latency, jitter can be caused by your local network, wifi, or device, but usually the culprit is your ISP.

Wifi Interference

Among the components of your local network, Wifi interference causes the most problems for video calls. Common Causes of Wifi Interference include concrete, metal, and mirrors, along with microwaves, cordless land-line phones, baby monitors, neighbor's wifi, and other wireless electronics. Read more about interference here.

Wifi interference is particularly a problem with video calls. Don't be surprised if a location in your home/office has no wifi issues downloading YouTube videos, but constant video call problems. The requirements for a live video call are different. Because the audio/video is being created in real-time, interference in the connection will cause more problems as none of it can be buffered (downloaded now to display latter).

Practical Tips

1) If your bandwidth is relatively low, make sure nobody at your home/office is watching a video (e.g. YouTube) or uploading a large files.

2) If using WiFi, check for things that might be interfering with the WiFi signal. Also, check if you are too far from the Wifi router.

3) Try another time and day and try to connect to other people.

4) If you are using a tablet or phone try using something else. If using a computer, make sure there are no other apps running that are taking up a lot of processing power.

5) Pause use of screen share, document camera, or toggle off video.

Answers to help questions can also be accessed within your Blink Lesson account by click "Help" from the top menu