I've noticed that when I or my conversation partner moves around (physically)--gesticulating, or nodding, etc.--the videochat lags and sometimes even freezes. This happens whether it's Skype, Google Hangouts, Zoom, etc.

Is this a real phenomenon, or a coincidence? (Could it be that moving more requires sending more data--since more pixels have shifted--which slows the app down?)

closed as too broad by ale, serenesat, Rubén, jonsca Jan 30 '18 at 3:18

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.


Yes, it is a real phenomenon, because video signal is compressed by converting a sequence of frames to "incremental updates". When there is more motion, there is more to update on the screen. From Wikipedia:

pixel groups or blocks of pixels are compared from one frame to the next, and the video compression codec sends only the differences within those blocks. In areas of video with more motion, the compression must encode more data to keep up with the larger number of pixels that are changing. Commonly during explosions, flames, flocks of animals, and in some panning shots, the high-frequency detail leads to quality decreases or to increases in the variable bitrate.

The practical conclusion is to avoid unnecessary gesticulation and other motion in videochat when your connection is slow.

Not the answer you're looking for? Browse other questions tagged or ask your own question.