Everything 'Technical' about AirPlay to Mac

[kvic]

This thread is not a place for debating whether one finds 'AirPlay to Mac' useful or not nor whether one likes it or not.

So what's it about? macOS Monterey introduces a new feature, 'AirPlay to Mac' which allows iOS devices as well as Mac's mirroring or extending display to another Mac. Basically macOS can act the role as an AirPlay receiver just like e.g. Apple TV for visual and audio. This is not new as some third-party effort could do this for many years. But beginning with Monterey, this feature gets first-class citizen treatment from Apple itself.

There are potentially many useful scenarios e.g. in classrooms, meeting rooms, at home, at clients' premise and etc. While the thread is not about discussing & debating such scenarios, by exploring the 'technical' capabilities of 'AirPlay to Mac', hopefully one will find a place where he/she could make good use of this new feature. Personally I expect this feature to substitute Target Display Mode for many users.

Details of 'AirPlay to Mac' is lacking. So far I found that one closer-look into this feature is from this YouTube video by Mr. Macintosh. Many outstanding questions e.g.

• maximum supported screen resolution; also video codec, encoding quality (adjustable?)
• maximum supported audio quality (useful to some ppl perhaps not most); like sampling frequency, bit-rate..
• latency between AirPlay sender & the Mac receiver in mirroring/extending visual and audio
• any details in hardware requirements beyond Apple's current brief doc
  • good news is from the above video, at the moment any Mac as long as you manage to install Monterey will be able to act as AirPlay receiver

Reading some of the comments online, seems to me that older Mac and iOS devices as AirPlay senders running older versions of macOS or iOS will be limited to a lower screen resolution. That's perhaps not surprising. I recall for a long while AirPlay protocol only supported up to max 1080p. I have the feeling that newer Mac's (as AirPlay sender) running Monterey should do native resolution (as per the receiver Mac). If not, perhaps up to 4K.

So let the fun begin!

 

[mrs2r]

Tested AirPlay from a 2020 Intel 13” MacBook Pro on 10.15.7 to a 2021 M1 24” iMac running macOS 12.0 and it is currently limited to 1080p. Both mirroring and extending the screen from the MacBook Pro to the iMac is blurry.

 

[kvic]

I believe only macOS Monterey onwards comes with a refreshed AirPlay protocol that supports >1080p. So when you update your AirPlay sender (2020 13-inch MBP) to Monterey, I think 4K on M1 24-inch iMac is achievable (that's still less than 4.5K native resolution).

There are also recent iMac's with 5K display or Mac Pro's with 6K or above. Whether native resolutions will be supported is still in the air. >4K real-time encoding/decoding (H.264 or HEVC) is shuffling lots of data. So understandably native resolutions will be limited to machines with recent GPU's. That assumes in the rare event some combinations of models will get supported.

 

[mrs2r]

Interesting. My MacBook Pro is my primary work machine and can't upgrade to macOS Monterey for some time. Just ordered the USB-C Luna Display from Astropad and will give that a try in the meantime.

To be honest I bought the iMac expecting to be able to use it as an external display and was about to return it until I learned that AirPlay to Mac coming. I was unaware that Target Display Mode was even a thing and no longer supported. I just expected it to work.

 

[Diskutant]

I believe only macOS Monterey onwards comes with a refreshed AirPlay protocol that supports >1080p.

When I use my TV as an external display via AirPlay it is 4K, and I'm on BigSur.

edit: I could swear I had it at 4k in the past, the UI was barely readable because it was so tiny. But now I try it and it's 1080P only. I guess I'm losing my mind.

 

[kvic]

Interesting. My MacBook Pro is my primary work machine and can't upgrade to macOS Monterey for some time. Just ordered the USB-C Luna Display from Astropad and will give that a try in the meantime.

To be honest I bought the iMac expecting to be able to use it as an external display and was about to return it until I learned that AirPlay to Mac coming. I was unaware that Target Display Mode was even a thing and no longer supported. I just expected it to work.

I read that LunaDisplay doesn't support Retina display. Hence, you may see another kind of blurriness on M1 24-inch iMac. Do let us know your experience when you get the chance to test it.

LunaDisplay claims that their LIQUID technology has very good latency among the peers:

• LunaDisplay/LIQUID - 11.32ms
• AirDisplay - 53ms
• Duet Display - 95ms
• 'AirPlay to Mac' - ?

Let's hope 'AirPlay to Mac' could do <15ms latency AND support Retina displays.

 

[Fomalnauto]

This thread is not a place for debating whether one finds 'AirPlay to Mac' useful or not nor whether one likes it or not.

So what's it about? macOS Monterey introduces a new feature, 'AirPlay to Mac' which allows iOS devices as well as Mac's mirroring or extending display to another Mac. Basically macOS can act the role as an AirPlay receiver just like e.g. Apple TV for visual and audio. This is not new as some third-party effort could do this for many years. But beginning with Monterey, this feature gets first-class citizen treatment from Apple itself.

There are potentially many useful scenarios e.g. in classrooms, meeting rooms, at home, at clients' premise and etc. While the thread is not about discussing & debating such scenarios, by exploring the 'technical' capabilities of 'AirPlay to Mac', hopefully one will find a place where he/she could make good use of this new feature. Personally I expect this feature to substitute Target Display Mode for many users.

Details of 'AirPlay to Mac' is lacking. So far I found that one closer-look into this feature is from this YouTube video by Mr. Macintosh. Many outstanding questions e.g.

• maximum supported screen resolution; also video codec, encoding quality (adjustable?)
• maximum supported audio quality (useful to some ppl perhaps not most); like sampling frequency, bit-rate..
• latency between AirPlay sender & the Mac receiver in mirroring/extending visual and audio
• any details in hardware requirements beyond Apple's current brief doc
  • good news is from the above video, at the moment any Mac as long as you manage to install Monterey will be able to act as AirPlay receiver

Reading some of the comments online, seems to me that older Mac and iOS devices as AirPlay senders running older versions of macOS or iOS will be limited to a lower screen resolution. That's perhaps not surprising. I recall for a long while AirPlay protocol only supported up to max 1080p. I have the feeling that newer Mac's (as AirPlay sender) running Monterey should do native resolution (as per the receiver Mac). If not, perhaps up to 4K.

So let the f

As said that "any Mac as long as you manage to install Monterey will be able to act as AirPlay receiver"
But the weird thing is I totally can't definitely find the airplay option under the Share content,My iMac is late 2015 imac27 5k

 

[kvic]

@Fomalnauto you have to install Monterey beta 1 on your 2015 27-inch 5K iMac (that will act as AirPay receiver). The optional checkbox 'AirPlay Receiver' could be found in System Preferences > Sharing i.e. listed together with Screen Sharing, Remote Login, File Sharing etc.

So just to reaffirm my understanding of your situation: you have Monterey installed on the iMac but 'AirPlay Receiver' checkbox is not available there?

 

[Fomalnauto]

@kvic Thanks for your reply!
The thing is no matter I upgraded from Big sur or Completely reinstalled Monterey,there was no 'Airplay Reciever' option.
Kindda weird huh!

 

[iStorm]

As said that "any Mac as long as you manage to install Monterey will be able to act as AirPlay receiver"
But the weird thing is I totally can't definitely find the airplay option under the Share content,My iMac is late 2015 imac27 5k

I think there might be some confusion or incorrect assumptions on which Macs will support AirPlay to Mac. The video somewhat sounds like all Macs running Monterey will support it, but I don't think that's actually the case.

These are the compatible models according to Apple's site, which was briefly mentioned in the video as well:

Available on MacBook Pro (2018 and later), MacBook Air (2018 and later), iMac (2019 and later), iMac Pro (2017), Mac mini (2020 and later), Mac Pro (2019), iPhone 7 and later, iPad Pro (2nd generation and later), iPad Air (3rd generation and later), iPad (6th generation and later), and iPad mini (5th generation and later). Older iPhone, iPad, and Mac models may share content at a lower resolution to supported Mac models when “Allow AirPlay for” is set to “Everyone” or “Anyone on the same network” in Sharing preferences.​

Now in the video, it worked for him on a 2016 12" MacBook running an official Monterey install, so I'm curious if Apple mistakenly left out the MacBook models in their footnote. (Or perhaps it's a "bug" in the beta and shouldn't have been allowed.) For the 2013 MacBook Pro, he was using an unofficial/patched install of Monterey which probably triggered the feature to be available since it could be spoofing a supported model.

 

[MrMacintoshBlog]

This thread is not a place for debating whether one finds 'AirPlay to Mac' useful or not nor whether one likes it or not.

.....

So let the fun begin!

Excellent thread @kvic !

You have brought up some great points along with @iStorm

I tried to put together as many test as I could in a short video. I think official requirements are still up in the air!

For example, I have no clue what the deal is with the 2018 T2 Mac Mini. It is NOT included in the requirements list but can act as an AirPlay receiver with full Apple ID seamless connection "Current User" and 4k resolution!

I also missed out on that for macOS Big Sur and below do not support "Current User seamless Apple ID Connection" and only support a maximum of 1080p Resolution.


Like @iStorm mentioned, how can my 2016 12" MacBook act as a receiver but not @Fomalnauto's 2015 iMac?

As to some of the outstanding questions -

• maximum supported screen resolution; also video codec, encoding quality (adjustable?) As of now it looks like

So far 4k, but I have 12 installing on a 2015 5k iMac to find out for sure. I have not tested video codec or encoding quality.

• maximum supported audio quality (useful to some ppl perhaps not most); like sampling frequency, bit-rate..

I also have not tested supported audio quality, but did make a quick video going over AirPlay 2 Speaker Controls ->

• latency between AirPlay sender & the Mac receiver in mirroring/extending visual and audio

The feel of the display was pretty good and I was able to run a quick test which looks like 32ms (See attached image)

• any details in hardware requirements beyond Apple's current brief doc
  • good news is from the above video, at the moment any Mac as long as you manage to install Monterey will be able to act as AirPlay receiver

Correct. I am testing the iMac 17,1 to see if it's a bug or not and will be able to report back soon.


Let me know if anyone has any questions!

 

[Gregintosh]

My question is if I can stream my MacBook Pro M1 to it and use the full resolution. I am not talking about 4.5k native, just whatever the "retina" or "HiDPI" version is. I don't want everything to be small on the screen, just sharp.

 

[MrMacintoshBlog]

@Fomalnauto

AirPlay Receiver​

Known Issues​

• AirPlay Receiver doesn’t appear in System Preferences > Sharing on unsupported hardware. (78170150)

I can confirm that AirPlay Receiver does not show up for a 2015 iMac running Monterey.

 

[Fomalnauto]

Thanks very much for your reply

@Fomalnauto

AirPlay Receiver​

Known Issues​

• AirPlay Receiver doesn’t appear in System Preferences > Sharing on unsupported hardware. (78170150)

I can confirm that AirPlay Receiver does not show up for a 2015 iMac running Monterey.

Thank you for the testing
Maybe it is a bug
Wish to see it coming in beta2

 

[kvic]

I went through the Apple officially supported list more closely. It seems the pattern or cut off line is pretty simple. Any Mac with Intel "8th gen processors" (marketing moniker) or newer + iMac Pro + MacPro7,1 + any Mac with Apple's own chips support 'AirPlay Receiver' feature.

Let's forget iMac Pro, Mac Pro and Apple M1 for a moment for obvious reasons with support. It seems the "8th gen processor" cut off has no sound 'technical" reasons. We could guess it's most likely a decision by the marketing dept.

Attached is Intel GPUs' media capability (a set of fixed functions under the QuickSync moniker). We could see the lowest common denominator with 4K encode/decode support is H.264. Hence, very likely that's the common video format to be used by most Mac's with "AirPlay to Mac" support. In other words, likely 4K is the maximum resolution for the first incarnation of the feature. Note that some 7th gen & 8th gen processors have the same UHD 630 - class gpu that itself is little to no difference from HD 630 gpu in "Intel 6th gen processors."

So Apple's engineering dept perhaps put in a set of hard-coded check on processor id to limit "AirPlay to Mac" to their official stance of supported models. That opens the door to tinkerers perhaps bringing the "AirPlay to Mac" feature to older and officially unsupported but 'technically' no different Mac's. @ClassicII

 

[kvic]

If 'AirPlay to Mac' is indeed cap'ed at max 4K, it's still superior to the old Target Display Mode which as a matter of fact supports up to only 2K. To make 4K looks good on a 4.5K, 5K or 6K screen, lots of tricks could be done on the receiver end.

For example, Apple could come up with something similar to AMD's FidelityFX Super Resolution. This would work very well with moving pictures even though the 4k resolution is scaled up a bit to fully cover, say, a 5K screen.

For contents such as UI elements including fonts, perhaps it's worth noting if they appear slightly bigger than the native ones on the Mac receiver end. With Apple's attention to details, I guess that won't be the case or very noticeable. Nevertheless, worth checking out.

Thinking about it. The feature will be a big flop if UI elements appear bigger than native ones on the Mac receiver end. To mitigate the situation, Apple engineers will have to tackle a mix of mismatched screen resolutions between the sender Mac and the receiver Mac. To avoid the hassle & non-elegant crap, limiting 'AirPlay to Mac' to Mac's consisting of a narrow subset of screen resolution seems the way out.

However, since MacPro7,1 is also supported, there is the possibility of people AirPlay from a tiny M1 MacBook Air to a 6K screen. I wonder how Apple would make this situation look good on the receiver end. There is certainly surprise, good or bad.

 

[helix21]

Anyone tried it on a 5k monitor / 2019 27" iMac as a receiver?

Is it limited to 4k with black bars (like on the M1 4.5K iMac photo)? Is it retina?

I am hoping to Airplay from a work 16" MBP to my personal 2019 27" 5K iMac. I couldn't find any solution (Luna etc) that could transfer the 5k retina signal.

Can this do it?

 

[kvic]

Is it limited to 4k with black bars (like on the M1 4.5K iMac photo)? Is it retina?

Is this real? Where did you see it? Perhaps I didn't pay enough attention in people's review.

4.5K = 4480 x 2520
4K = 3840 x 2160

Both dimensions are a constant scaling factor thought not integral. For full-screen movies, should be easy to scale up to cover the full 4.5K screen without noticeable defects. For UI elements, a bit challenging.

In case it's indeed a rectangular "black frame", the frame is thin enough I guess not to be distractive on a 4.5K screen. On a 5K or 6K screen, the frame could be pretty fat. That's big flop in my opinion as Target Display Mode replacement if real.

Nevertheless, it's still retina. should be crisp. Just fat "black frame" (if true)

EDIT:

No black bars (or I call it 'black frame') on M1 iMac. See attached screenshot from the video linked in post #1. So like I said all along in this thread, 4K contents are scaled up to 4.5K to fully cover the screen.

Expect Apple to do something similar for 5K or 6K screens. Someone having tried could confirm my educated guess. Doing it from 4K to 4.5K is hardly noticeable. From 4K to 6K, I wonder what 'magic' Apple puts in.

EDIT 2:

I think I figure out what happened. When you extend your Sender Mac to a Receiver Mac, the chosen resolution will be 4K which will be nicely scaled up to 4.5K on M1 iMac. That's what happened in the attached pic.

However, when you choose to mirror your Sender Mac to a Receiver Mac, obviously the default chosen "resolution" or rather the aspect ratio will be the one you set for the Sender Mac. To avoid the black vertical bars is a trivial exercise.

Alright, I still have faith in 'AirPlay to Mac' as Target Display Mode replacement! Guys, keep your observations (right or wrong) pour in.

 

[Gregintosh]

If you send 4K signal to a 4.5k iMac will the display retain its sharpness even though it’s being scaled? Or will it appear less sharp than the iMacs running on its own?

I would love to use the new iMac as a display for a MacBook. The idea for me would be then to use the MacBook as my primary computer since I travel and simply dock it with my iMac when I’m at home and need to do work stuff, thus avoiding having to duplicate all my files, apps, etc.

 

[MrMacintoshBlog]

Anyone tried it on a 5k monitor / 2019 27" iMac as a receiver?

Is it limited to 4k with black bars (like on the M1 4.5K iMac photo)? Is it retina?

I am hoping to Airplay from a work 16" MBP to my personal 2019 27" 5K iMac. I couldn't find any solution (Luna etc) that could transfer the 5k retina signal.

Can this do it?

If you send 4K signal to a 4.5k iMac will the display retain its sharpness even though it’s being scaled? Or will it appear less sharp than the iMacs running on its own?

I would love to use the new iMac as a display for a MacBook. The idea for me would be then to use the MacBook as my primary computer since I travel and simply dock it with my iMac when I’m at home and need to do work stuff, thus avoiding having to duplicate all my files, apps, etc.

I am going to try and get my 2015 5k working somehow so we can test this.

4k looks great on the 24" iMac sharp with a very slight delay. Not bad for the first beta!

 

[kvic]

If you send 4K signal to a 4.5k iMac will the display retain its sharpness even though it’s being scaled? Or will it appear less sharp than the iMacs running on its own?

I would love to use the new iMac as a display for a MacBook. The idea for me would be then to use the MacBook as my primary computer since I travel and simply dock it with my iMac when I’m at home and need to do work stuff, thus avoiding having to duplicate all my files, apps, etc.

4K to 4.5K is only scaling up by 17% equally on both dimensions. It appears not differentiable from the native resolution. Check out Mr.Macintosh video (available in 4K or 2K) linked in post #1.

Video quality is quite subjective (even though much less so than audio quality). So eventually you would have to judge it yourself. I believe for your workflow 'AirPlay to Mac' will be a very good use case.

 

[kvic]

Latency comparisons from Youtube LTT Channel.

While it's only comparing among Sidecar, LunaDisplay and native, 'AirPlay to Mac' is really a different name for 'Sidecar' into Mac. Shouldn't be much different in the underlying spinning. From Sidecar, we could glimpse how 'AirPlay to Mac' does on latency front.

Also available Latency over WiFi. See attached.

 

[kvic]

I did a quick test from the 1st iMac in the 1st column (on ETH and WiFi, running Big Sur) of my sig. to the 3rd iMac in the 1st column (on WiFi, running Monterey DP1). It worked, but I did’t run the test for a long time, so I cannot guarantee stability.

This is an interesting development! Decade old iMacs (with upgraded metal GPU) running Monterey can do 'AirPlay to Mac.' Would be great if you could double check both CPU & GPU power consumptions on both Sender Mac and Receiver Mac. A test case could be playback a 720p video from youtube in Safari on desktop (i.e. not full screen), or a h.264 720p video file in iTune/QuickTime player (also not full screen):

• 'CPU package power'
• 'GPU Rail' / GPU package power

as well as how smooth the video playback looks like on the Receiver Mac.

Mobile AMD GPUs at idle consume only a few watt. In the teen's wattage when driving the LCD panel for video. That's assuming 'AirPlay to Mac' encode & decode are handled by QuickSync which consumes less than one watt. The goal here is looking for a 'virtual monitor' technology which consumes the least power. @dfranetic @Chow Andrew @Ausdauersportler

If this is possible on an 'upgraded decade old' iMac, little reason newer iMac's can't do, except one remaining question regarding 4K to 5K scaling.

 

[RossGGG]

I'm having some difficulty using Airplay to Mac as an extended display smoothly. It seems like, when connecting from one Mac to another, either the interface scaling/dpi settings or the limited display resolutions fail to create a seamless experience on the airplay display and isn't quite comfortable to work with. Also, the aspect ratio seems to be limited to one option, which can lead to undesirable black bars depending on your devices.

The only available output resolutions to an extended AirPlay display seem to be as follows, regardless of what device you connect to. There is a "Show All Resolutions" checkbox, but it only provides "low resolution" versions of the two lower resolutions already in the list.

3840 x 2160 2560 x 1440 (low resolution) 1920 x 1080 1280 x 720

When I extend my display from my M1 MacBook Pro to my M1 iMac, it uses the correct 1.78 aspect ratio and the image fills the iMac display from edge-to-edge, however there is not a resolution option that matches the "Default" scale options that the iMac traditionally uses (2240x2160). The "More Space" scale option is there (2560 x 1440), but only as a "low resolution" version that results in the UI looking slightly blurry. The 4k option (3840 x 2160) looks sharp, but the UI becomes impossibly tiny on the iMac display. It actually does look native and great if I swap the AirPlay image over to my external 4k Samsung display that is attached to the iMac.

The situation is even more sad if I try to extend the display from the M1 iMac over to the M1 MacBook Pro. Since the MacBook display's aspect ratio is 1.6, all of the available resolution options result in black bars at the top and bottom of the display. On top of that, none of them are close to the comfortable options for that display (1440x900 or 1680x1050).

Here are some examples:
M1 MacBook Pro Airplay Extended out to M1 iMac
3840 x 2160 - Tiny UI

2560 x 1440 (low resolution) - The UI looks a bit blurry, but it's hard to see in the photo

1920x1080 - Looks decent, but UI is a bit larger than what would feel natural

M1 iMac Airplay Extended out to M1 MacBook Pro
3840 x 2160 - Tiny UI and Black Bars

2560 x 1440 (low resolution) - Small UI, slightly blurry, and Black Bars

1920 x 1280 - Decent UI Size, but Black Bars

1280 x 720 - Large UI and Black Bars

 

[kvic]

@RossGGG, this is great investigative work.

It upsets me a bit Apple only offers very limited resolutions (& aspect ratios) in "extend" mode: 4K, 2K (non-HiDPI), 1080p and 720p. The black bars are particularly upsetting when used between Mac to Mac. I don't understand why Apple can't create a virtual frame buffer that matches the target display's perceived resolution (& aspect ratio). Hopefully with more time next year's version will bring improvement and be up to Apple standard.

In "mirror" mode, if you select the primary Mac's resolution/aspect ratio to match the target display's, do you still see black bars? I would guess Apple might have "mirror" mode in mind as primary usage when they do the Mac to Mac scenario.