my airplay mirroring is choppy

Hate to say it, but I've tested this on multiple Macs with a couple of different AppleTV's and they all have the same problem. I've tried this using both WiFi as well as direct ethernet connection. There is a serious flaw in the MacOS implementation of Airplay Mirroring that doesn't exist under iOS. For instance, when I connect various iPhone and iPads to the AppleTV, the mirroring works flawlessly. Never a hiccup. Only under MacOS does this problem appear. And it happens Every. Single. Time.

I've tested every possible network LAN configuration I could think of.... to no avail. And I'm running gigabit ethernet throughout. Also tested with WiFi and turning off all QoS, etc. Nothing changes. Even testing 10+ computers with different versions of MacOS (10.10.x - 10.12.x) and they all have the identical problem. However, iOS mirroring works flawlessly. There is something vastly different with the MacOS implementation of Airplay than the iOS version. It appears Apple needs to seriously address this persistent problem.

Hi. Are you familiar with the difference between mirroring and basic AirPlay (video streaming)? Mirroring requires the graphics chip to convert the screen buffer to video, while basic AirPlay just works with the video you're watching. The following describes this in more detail.

Video AirPlay works in two modes. Basic AirPlay just sends the video URL to Apple TV, which then streams it directly. This usually works best since there's no double transmission. You're using basic AirPlay when the video player on your device goes black and says "This video is playing on Apple TV". On a computer, you enable this using the AirPlay icon that appears in the controls of a screen video player object, inside the browser or other app. On iPad or iPhone, use the AirPlay controls on the right hand pane of the iOS 10 Control Center (on iPhone, tap the arrow with circles icon at the bottom), or the AirPlay icon in the video player. An app can prevent basic AirPlay, and a website may have requirements that only work in the browser, so basic AirPlay may not always work.

The other mode is Mirroring, which generates an H.264 video stream from the device frame buffer and transmits it over WiFi to Apple TV. This video compression inherently limits resolution, and may have trouble with fast motion. On iPad or iPhone, mirroring is on the left hand pane of the iOS 10 Control Center. On a Mac computer, you access this mode from the AirPlay icon in the main menu bar. It lets you mirror the main display, or create a new display, extending the desktop. But remember that the data sent to the Apple TV is always being converted to a live video stream. Unlike a normal wired monitor connection, actual display frame buffer pixels are not transmitted. When you put the iPad or iPhone video player into full screen mode, mirroring may automatically switch to basic AirPlay. If the server doesn't support basic AirPlay, this may prevent mirroring full screen video.

Working fine on my system and there is no widespread issue.

Mirroring a Mac is much more intensive. To see a current status of the network, get a report. Test on another network (preferably a controlled one like Apple's).

I can guarantee, with absolute certainty, that it isn't my network. We run 4K/6K/8K RED cam footage over this network regularly. Many of the machines I tested on were running 1Gb/2Gb and even 10Gb connections via a very high-end Cisco switch.

Again, it is working just fine here and for the majority. The difference is the network, (if you have other activity occurring on the network when you attempt to mirror then that will be a factor)you can either do further troubleshooting or take it elsewhere (or to Apple) for testing.

At the AppleTV port it is getting 106MB/sec peak with an average of 98MB/sec. Latency is less than 2ms. No lost packets. Source Mac has nearly identical report regardless of which machine I perform tests. I have tested this on other 1Gb Ethernet machines. All getting nearly identical performance. Machines tested include the new Mac Pro 12-core w/ 64GB RAM and two 2015 iMacs both with i7 processors and 32GB RAM. Single apps running on all machines with less than 10% CPU usage through testing.

Hi Doug Stringham. It sounds like you have a very high performance wired network. If you're using DHCP for Apple TV, you might check the DHCP server logs. Apple TV on ethernet can generate a lot of extra DHCP lease renewal requests. If it's doing that, it might be a cause for glitches in playback. Also, it may not matter, but the Apple TV ethernet interface is 10/100 Mb/s only.

It may be an issue with the router, mirroring requires more from the network. To get a report to to istumbler.net, look for signal strength and noise

There is a difference between streaming video and mirroring a display. It also doesn't rule out a network issue. To verify you would need to get a proper report.

Have you tried restarting your imac and/or appletv? Maybe that will work. One question do you have the remote that came with the apple tv?