why are all web cams 2 mpixels.. is it due to a limitation on speed or just to keep the cost down. the question also cover 30fps. Thank you

First off they are not limited in hardware as you can use almost any digital camcorder as a webcam.

If you buy a "webcam" specifically manufactured as a webcam then the basic format is 2mpixels @ 30fps as that is the standard transfer rate via standard servers and browsers.

Hence the perceived limit is a software limit due to live transmission requirements.

You could say it is the web that limits the cam. And as such the manufacturers of strictly webcams have no reason to build a better cam as it would cost more for no increase in performance.

Much more detail here:

HowStuffWorks "How Webcams Work"


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