4th Gen Apple TV - laggy when using AirPlay

but for some reason when I use AirPlay from my iPhone 7 Plus, video appears very laggy.

Have you tried restarting your iPhone yet?

1. Press and hold the Sleep/Wake button until the red slider appears.
2. Drag the slider to turn your device completely off.
3. After the device turns off, press and hold the Sleep/Wake button again until you see the Apple logo.

Get help with AirPlay and AirPlay Mirroring on your iPhone, iPad, or iPod touch - Apple Support

Airplay is done over the local network so internet speed isn't relevant. If it's mirroring, as opposed to basic AirPlay, then that would require even more resources from your network. You would need to test the 4th gen on the other network for it to be an accurate comparison.

If you haven't already done so restart the router and make sure it's up to date.

If on wifi try connecting via ATV Ethernet

To see a current status of the network get a report from istumbler, netstumbler or similar. Look for signal strength, noise, nearby networks.

Hi. Are you using mirroring or basic AirPlay? Is the video on the phone or streaming from the internet? You said you're using 3 routers. How are they connected, and is the phone and Apple TV on the same one?

I don't really know how these particular devices work, they sound like some kind of network extender to me or may allow the devices to roam from one point to another (but I may well be wrong) and the Apple TV doesn't work particularly well with extended networks.

The best way to deal with large range requirements (IMO) is to use access points connected by ethernet (this is how my set up works), I'm aware that some set ups use a similar configuration by connecting the access points through powerline adaptors and in many cases they may work equally as well, but powerline adaptors seem to have their own issues too in a number of cases.

You shouldn't really have any problems playing a video that resides on your mobile device by AirPlay, it's AirPlay in about it's most basic form.

My point was I don't think you are mirroring (but could be wrong), when I try to mirror a video on my phone it defaults to basic AirPlay. When you start AirPlay does the screen go blank with a message that AirPlay is being used or do you see the video on both devices.

If it's a video it's best to use basic AirPlay as that sends the video directly to the Apple TV as opposed to mirroring the whole screen

I don't know about anybody else but when I play a video that's already on my device and in the video app, then regardless of whether I choose mirroring or not, it invariably defaults to basic AirPlay

I don't know about anybody else but when I play a video that's already on my device and in the video app, then regardless of whether I choose mirroring or not, it invariably defaults to basic AirPlay

Thanks. I was wondering if the lag could be due to multiple transmissions. Both devices are on the main router, which rules that out.