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Comment by dheera | Hacker News Reader

Is it possible to make an IP camera appear on the other end as /dev/videoX with near zero latency? Even with LAN ping times of <2ms I routinely get >200ms of latency with IP cameras, sometimes as much as 1000ms, and can't figure out a good solution.

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There were a bunch of people experimenting with using RaspberryPis for low latency drone FPV video. Turns out for some use cases WiFi in it's standard config is a big part of the "getting below a few hundred milliseconds latency" problem. (Note: trying for low latency on 1080p video is making life harder for yourself too. If you don't _need_ 2 megapixel frames, go smaller. 720 or 600 lines might be fine. Drone FPV often uses 525 line analog video.)

I've got a setup I built based on this: https://befinitiv.wordpress.com/wifibroadcast-analog-like-tr... that's well below 100ms if latency. It's still not as good as analog video for fast drones though.

These days most drone people just blow money on the new-ish DJI digital video stuff (which works on non-DJI drones). It's pretty spectacular, but it's over a grand (in AUD) worth of gear so for now I'm sticking with my old analog video gear.

I have to imagine that's mostly due to encoding, right? I wonder what the cheapest format to get a hw encoder for is.

In the past, w/ Axis cameras, I have enabled two streams, the high quality, high res. h.264 with high latency, and a lower resolution mjpeg stream with much lower latency.

You need to tune the buffers on both the sender and the receiver, as well as choose a codec with low latency. It takes some work, but you should be able to get it below a second without too much trouble.

I think you could probably achieve that with v4l2loopback and ffmpeg. I've done something similar in the past and it works.

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