[imaginenore]

What kind of computer would one need to encode H.264 1080p in real time?

(I assume it's all done on the CPU, not the GPU)

[xgbi]

We (linphone) do H264 software encoding and reach 720 on high-end iPhones (5s and more). So 1080 should be doable in realtime with, say, 20 fps, on an i5 I'd say?

[ex3ndr]

Are you using hardware accelerated encoding on iOS?

[xgbi]

As I said, software encoding. Hardware encoding is coming but not yet there.

[Scaevolus]

It can't be worse than VP9, which is what Hangouts has been using recently. It stutters a lot on most laptops.

[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.

[the8472]

depends on how good you want the results to be. software encoders generally allow you to make tradeoffs in the bitrate-cpu-quality triangle.