[snuxoll]

Depends on bitrate. I mean, my old Lumia 920 with a underpowered dual-core ARM CPU could encode 1080p at 10Mbits/sec from the camera module - really shouldn't be an issue for any modern PC to have video-conference quality video.

[imaginenore]

You're confusing hardware encoding with software encoding. Your phone doesn't do it on its CPU (or GPU for that matter). The camera module usually has a separate chip for the encoding.

[talonstriker]

It's not part of the Camera module, but you're right that there is a dedicated h/w core for it.

Some lower end SoCs just do it in the DSP.

[ZeroGravitas]

Some of the speed comes at a cost of lower compression. Not that big a deal when it only has to got from camera to SD card, but important when it needs to get transmitted across the mobile internet in real-time.