Apple TV airplay video choppy

I searched and didn’t find much that was related to my issue.

I have an iPhone 6s Plus on 12.1

And an Apple TV, not 4K I don’t think. Has the touch pad remote and it’s about 1-1/2yr old.

Whenever I airplay video it’s slow and choppy.

My WiFi’s Speedtest on iPhone is 19mb/sec

I thought at first it might be the GoPro video I was airplaying from my phone, maybe too much bitrate, but hen I tried just a plain video **** with my phone and it does same thing.

Just wondering if there was settings in Apple TV or maybe HDMI cable could be causing it