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When using airplay from mac to apple tv it lags/freezes, but works fine with iPhone

Ive recently bought a apple tv 3rd generation. Everything seems to be working fine with airplay from my iphone to apple tv, but when I try and use airplay from my mac book pro, it is extremely slow, and if I try and stream a movie or something its that terrible it is unwatchable and usually freezes then stops. How can I resolve this problem? is this a problem with the apple tv?

Posted on Aug 21, 2013 4:55 AM

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208 replies

Jun 15, 2015 2:41 PM in response to krissoundz

Yes this issue seems counter-intuitive until one thinks about how this works. I am a systems programmer, but since I do not have access to the internals of OS X, I can only make an educated guess as to the root of this "problem."


There are two distinct parts to Airplay: audio/video and mirroring. When our iDevices send audio or audio/video or photo's to the AppleTV, it sends the audio or audio/video information as a stream of data that is then decoded by the AppleTV in a way that preserves temporal integrity. Think of this as the same way you receive a Netflix movie or a streaming audio song. In fact, it's the same concept exactly, and we all know that Netflix or Spotify would be useless if it was choppy or laggy. This is an efficient means of transporting data, hence it just works.


Mirroring involves the extra step that slows things down: scanning your screen and input audio which then has to be processed and packaged for transport locally from our MacBooks. Only then can it be sent over-the-air to the AppleTV. This is a necessary, incredibly processor intensive task that is the difference between using Airplay on our iDevices vs our more powerful computers. So why does mirroring work perfectly from our iDevices? Because Apple uses a trick that recognizes audio or audio/video streams from our iDevices and temporarily "switches" to the non-mirroring form of Airplay - have you ever noticed that when "mirroring" from an iPhone or iPad, as soon as you start a video, the TV screen gracefully fades out and then back in quickly to a full screen version of the multimedia? To confirm this hypothesis, try mirroring from a Safari page in iPad vs mirroring from a Safari page on Mac OS X. You'll notice that from the iPad, your AppleTV will show only the video in full-screen on the TV (non-mirroring) but from the computer, you'll see the web page and the video in an identical configuration as what you're seeing on your computer screen (mirroring). This way, the iPad and iPhone don't have to perform this extra "step" and everything stays smooth.


So why doesn't Apple employ this same technique on our expensive, powerful computers? I think it's because mirroring from a computer was designed to be more of a "second screen" for our PC's in which case we would be truly ****** if our AppleTV's could not mirror a webpage or application if video or audio/video was present whereas this is not important for iPads and iPhones. As annoying as this is, I fear that it is working as designed, and this problem will only get worst as CPU's move to mobile architectures to save energy unless Apple works on optimizing the efficiency of it's Airplay algorithms.


To address the post that mentioned that this all works much smoother from wired connections, this has to do with the fact that the algorithms to mirror vs stream audio/video only are much less efficient. It took 30 years of software optimization to learn how to efficiently stream audio/video (non-mirroring), but even if the scanning/processing step (mirroring) from our computers was wholly efficient, there is still way more information to send over the network to the AppleTV due to the way data must be packaged to truly mirror a screen.

Jun 25, 2015 1:15 PM in response to krissoundz

I encounter the same problem.

My Macbook Pro is in good condition, all the updates are done on both the Apple TV and The Mac. The lag is not always there but it comes back eventually. iPad or iPhone don't pose any kind of lag. The lag is both audio and video. the only way I manage to get rid of it is reboot both devices (sometimes more than once) and it gets back to normal, sometimes for a number of days, some other times only minutes.

Furthermore, i encountered a similar problem with bluetooth speakers and headphones. the audio only lags occasionally, which has led me to think the origin of this problem might be from the Mac itself rather than the Apple TV. I hope they fix the issues soon and won't wait for the release of El Capitan to correct this.

Jul 10, 2015 4:23 PM in response to krissoundz

Same issue here. I have:
Apple Tv 3

Macbook Pro Retina, Yosemite 10.10.3, i7 2,3Ghz, 16GB DDR3, Nvidia GT 750M
Asus AC68U
(so it should obviously work flawless)


First i tried with all wireless, no hope.

Wired the apple tv, no hope, actually made it worse.


This worked for me:


* Making a guest network and connecting macbook to that, kept te apple tv wired.


This changed everything. So no question that there are some interference issues with wireless settings. I guess the guest network runs on a different channel (main wireless is set to auto). Also that it probably only uses 2.4Ghz and not both/5Ghz.


I still wasn't completely happy, I felt it dropped some frames here and there, so I changed the apple tv hdmi output to 720p to make the bitstream smaller, which made it "perfect" (considering we live in 2015 it's absolute garbage).

Jul 15, 2015 12:12 PM in response to A 1977

Guys: THIS WORKS!! https://www.youtube.com/watch?v=LY2weHeKUI8



Thank you so much for linking to this video. The resolution is somewhat convoluted... but it works! No lagging when streaming between my Macbook Pro and Apple TV. What a shame the Muppets at Apple don't have a resolution and leave us to struggle alone. I thought we were meant to be valued customers?

When using airplay from mac to apple tv it lags/freezes, but works fine with iPhone

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