4K AirPlay?

[jafingi]

Does anyone know if AirPlay supports 4K streaming from iPhone? Would be so great to watch my videos in the proper resolution.

 

[MartyTannen1981]

https://forums.macrumors.com/thread...ort-for-4k-videos-from-icloud-photos.2070494/

https://forums.macrumors.com/thread...o-4k-airplay-streaming.2070317/#post-25099141

See here.

No. It won't work. No Airplay 4K, no iCloud Photo Library 4K...I can't believe it. Such a shame for a "4K" box

 

[benji888]

This is because the current iteration of AirPlay is only capable of 1080p. Apple announced AirPlay 2 in June, it appeared in the first 5 betas of iOS 11, then it was pulled, now it is coming in a future iOS 11 update.

AirPlay 2 should be giving us 4K support, I say "should" because apple has removed any references to it, I can't find tech specs on it. No date on when it will be available.

 

[Macalicious2011]

Does the 4K ATV support 4K AirPlay?

If so. What formats or what’s the max bitrate supported for h.264?

 

[priitv8]

... or what’s the max bitrate supported for h.264?

In my experience, it struggles with anything over 50Mbps, at least in H.265.
Haven't tested the breaking point for H.264 but 139Mbps is definitely too much

 

[waw74]

AirPlay 2 should be giving us 4K support, I say "should" because apple has removed any references to it, I can't find tech specs on it. No date on when it will be available.

it's not really scrubbed, it's still mentioned on the iOS 11 and home pod pages

Every reference i've seen to Airplay 2, was only about audio.

it's an updated standard that (i'm guessing) uses a broadcast instead of the multi-cast that Airplay uses.
it also probably gets rid of the 2 second buffer, now that wireless networks are a little more robust than in 2004 when it was introduced.
and it will add some control stuff for homekit integration.



it kinda sucks that apple has 3 different things, all named airplay
- airplay (audio only) - renamed from the original AirTunes
- airplay (video) - sends a file or web location to the aTV to play
- airplay (mirroring) - converts the video output to h.264 in real time, and streams that to the aTV.

for airplay to support 4k, they will probably have to change it to h.265. currently only the iPhone 7 and later, and some 2017 macs have hardware support for 265.
It's like when they announced mirroring, only macs/iOS devices after a certain version supported, because they have the hardware to support real time 264 encoding. otherwise, it's too processor/battery heavy

 

[dyzfnctional]

Does anyone know if airplay 2 support 4K? So I can get rid of hdmi cables or usbc etc.

 

[subjonas]

Does anyone know if airplay 2 support 4K? So I can get rid of hdmi cables or usbc etc.

Sadly, I don’t believe airplay 2 can handle 4K. I read up on it months ago though so I don’t have any links.

Another thing I’m wondering is whether an Apple TV 4K plays a 4K movie in 4K when accessing the movie from one’s computer iTunes movie library. It’s connected over WiFi but isn’t that different from airplay?

 

[benji888]

Sadly, I don’t believe airplay 2 can handle 4K. I read up on it months ago though so I don’t have any links.

Another thing I’m wondering is whether an Apple TV 4K plays a 4K movie in 4K when accessing the movie from one’s computer iTunes movie library. It’s connected over WiFi but isn’t that different from airplay?

Yes, that is not the same as using AirPlay.

If playing downloaded version over your local network, no, Apple only allows HD version to be downloaded, 4K can only be streamed, so, if playing via iCloud, and 4K version is available, yes.

 

[priitv8]

Yes, that is not the same as using AirPlay.

If playing downloaded version over your local network, no, Apple only allows HD version to be downloaded, 4K can only be streamed, so, if playing via iCloud, and 4K version is available, yes.

You could also have your own 4K videos taken with iPhone in your iTunes library. I don't see any reason, why they would not play back in native size over Home Sharing or AirPlay.
This picture shows my own movie playing back over Home Sharing (pulled from aTV) from my iTunes library.
I can equally well push it from my iTunes to aTV (AirPlay).
So I am thinking AirPlay does support 4K.

 

[subjonas]

Yes, that is not the same as using AirPlay.

If playing downloaded version over your local network, no, Apple only allows HD version to be downloaded, 4K can only be streamed, so, if playing via iCloud, and 4K version is available, yes.

As the above poster said, I’m wondering about 4k video that one might have imported into their local iTunes library and home shared to Apple TV. It doesn’t make sense to me that if 4k can be streamed from the internet to one’s router then to one’s Apple TV, it should be just as easy to “stream” 4k from one’s computer to router to Apple TV.

You could also have your own 4K videos taken with iPhone in your iTunes library. I don't see any reason, why they would not play back in native size over Home Sharing or AirPlay.
This picture shows my own movie playing back over Home Sharing (pulled from aTV) from my iTunes library.
I can equally well push it from my iTunes to aTV (AirPlay).
So I am thinking AirPlay does support 4K.

I agree, I don’t see why home sharing shouldn’t be able to support 4k playback, since it uses the same WiFi being used to stream 4k video from say Netflix. But I can’t confirm since I don’t have any 4k content in my iTunes to test and I haven’t been able to find any info online about it. I’m also unsure because airplay reportedly does not support 4k even though it utilizes WiFi (plus Bluetooth). I suppose I could test that to confirm when I get a chance. That’s not to say, a 4k tv may upscale a 4k movie that has been downscaled to 1080p by airplay.

But I guess from your picture, it confirms the 4k source content is being played in actual 4k via home share? I wonder if there’s a chance that iTunes downscaled it and it is being upscaled by the tv though.

 

[priitv8]

But I guess from your picture, it confirms the 4k source content is being played in actual 4k via home share? I wonder if there’s a chance that iTunes downscaled it and it is being upscaled by the tv though.

If that were the case, Natural Size should show 1080p. Like it does, when you play from your iCloud Photo Library, for example.
IMHO it shouldn't be that difficult to get 4K movie into your library. Shoot it on your contemporary iPhone or other smartphone, and you're set.

 

[subjonas]

If that were the case, Natural Size should show 1080p. Like it does, when you play from your iCloud Photo Library, for example.
IMHO it shouldn't be that difficult to get 4K movie into your library. Shoot it on your contemporary iPhone or other smartphone, and you're set.

Hm yes probably would show 1080. But you said you’re getting 4k via airplay too? That shouldn’t be possible. Everything I read says airplay doesn’t support 4k (4k content is downscaled).

I totally forgot my se supports 4k recording hahah. How do you get those numbers to show on your tv by the way?

 

[priitv8]

I totally forgot my se supports 4k recording hahah. How do you get those numbers to show on your tv by the way?

That’s the developer HUD. You need mac and Xcode to activate it.
https://www.redmondpie.com/check-apple-tv-4k-resolution-video-quality-connection-speed-heres-how/

 

[Tom Appleseed]

The reason Airplay won’t work in 4K is because currently it does not use WiFi to mirror content. It operates like the camera application on the Apple Watch. The content is streamed over Bluetooth to the Apple TV. If the resolution is to high, like 4K for example, then you would experience more latency. Quality of the image is determined by signal strength and the quality limitations of the content being streamed. I hope this helps you understand

 

[Ritsuka]

Uh, no. You aren't making sense.
AirPlay Video works with the Wi-Fi network you are currently on, if not, it uses Wi-Fi direct. And you can just AirPlay 4k.

 

[priitv8]

The reason Airplay won’t work in 4K is because currently it does not use WiFi to mirror content. It operates like the camera application on the Apple Watch. The content is streamed over Bluetooth to the Apple TV. If the resolution is to high, like 4K for example, then you would experience more latency. Quality of the image is determined by signal strength and the quality limitations of the content being streamed. I hope this helps you understand

AirPlay started its life in early 2000's as AirTunes. The target device was then AirPort Express and it worked over network, not Bluetooth. It has evolved a lot since then, but it never changed to Bluetooth for transport of streams.
Since about aTV 3, Rev. A, Apple has started using Bluetooth LTE as a beacon for proximity sensing and authentication (device setup when you bring iPhone close to it, but also handover protocol or even unlocking a Mac with Apple Watch). But the bulk of data is still lifted over ethernet, I believe. These are just my feelings, I have no hard facts to support that theory.

 

[Donfor39]

Is there anything I could check as my 4K Apple t.v. Fails to connect via Airplay 2.
Nice idea trying to authenticate via Xs
--edited--
Using airplay compatible sky soundbox

 

[cynics]

Streaming 4K isn't a trivial task. Depending a lot of variables such as codec, color bit depth, frame rate, receiving device, transmitting device, HDR, encode profile, the specific decoding software (VLC, Quicktime, built in players) etc there is a good chance you'll have problems outside the control of Apple.

Its really easy to get/make a 4k video that the AppleTV 4k can't decode. 4k@60hz HEVC HDR is especially troublesome and you can things like weird artifacts, color banding or even just a black screen.

This is the AppleTV 4k's attempt to decode "The World in HDR" its a 4k@60hz HDR but the video is encoded with Google VP9 video codec.



I ran it through handbrake and encoded it using h265 10bit however even then it was a balancing act to get a 4k@60hz HEVC HDR version that smoothly played but once it did I could home share and airplay from my 2013 iMac (doesn't have native HEVC support) to my AppleTV 4k.

I was actually impressed with how well MacOS and Quicktime was handling this file. I was able to play HEVC files in Quicktime on my iMac (decoding HEVC through software) that many third party players couldn't play nor could the AppleTV 4k which has hevc hardware decoding.

It took my iMacs slightly dated but still relevant quad core i5 1 1/2 HOURS to encode that 2 1/2 MINUTE 200mb clip. Maybe that will help illustrate why certain situations can't be handled by AirPlay where things need to be done in real time without a hick up. While I was using the original file "The World in HDR" that is a youtube clip which is why Google can't use software decoding for the AppleTV YouTube app to have 4k. Apple would need the hardware support to have reliable 4k HDR youtube. Admittedly that is an extreme example but it does still exist.

As far as 4k AirPlay I don't have nor do I feel like setting up Xcode like @priitv8. I also don't have the software, time or patient for pixel counting.

Things I did notice though since I have quite a few Apple products. Keep in mind I'm using the 4k@60hz HEVC HDR BT2020 10bit file I encoded above in all my examples below...

1. Decoding is done on the playback device when using Home Sharing. The above video gives me an error "The content isn't supported by Apple TV" on my non 4k 4th gen AppleTV. Plays fine on my AppleTV 4k. So no where in the chain is transcoding attempted.

2. When using AirPlay the decoding device is dependent the specific of what and how your are trying to Airplay..

If you are mirroring the original file is being decoded by the host and the entire screen is being encoded in h264 (using the resolution of the host devices current screen), sent to the receiver (AppleTV) which decodes that h264 stream.

If you don't mirror and AirPlay specific videos then it streams the original file for the receiver to decode (so yes you can AirPlay 4k. The caveat is if the receiver (AppleTV) can't decode the file several different things can happen, you getting an error, the video stutters, artifacts, color banding etc, or it just keeps kicking you out. So the same video that my 4th gen AppleTV gave me the error "Content not support on AppleTV" will AirPlay from my iPhone 6s but its can't play it, its a slide show of images playing at less than 1 fps. Again plays fine on my AppleTV 4k.

3. iCloud Photos automatically transcodes (very quickly I might add) to something that objectively looks worse then 1080p SDR (I checked using MacOS encoding tool) for device compatibly. So if you goto the tvOS photos app you aren't getting original quality if the media is using processes that aren't compatible with all Apple devices regardless if its an AppleTV 4k or not. The iCloud version can't even be compared to the original version playing on the same device. This is a picture of the aforementioned 4k HEVC HDR video taken from my AppleTV 4k, one being played in the Photos app, one being played in the Computers app (Home Sharing).



That is a picture of my TV taken from an iPhone 6S using lossy jpg, cropped in preview on my Mac and exported in an even lossier JPG so I could upload them here without exceeding upload data limit. If you click on them you can still clearly see the resolution difference.

4. Compatible format transfers are device specific. If I transfer the above original video (4k@60hz HEVC HDR) from my 2018 MBP to my 2013 iMac I get a 4k@60hz h264 file.

Original is left, compatibility version is on the right.

Now I ran into another issue. That compatible version is huge so I would assume the transcode wasn't very complex, ok whatever. However the compatible version will not play on the AppleTV using Home Sharing or AirPlay due to a "File format compatibility" so I assume the encode profile level is too high and is breaking something, I'm not really sure what is wrong with it. Keep in mind I can play the original version that looks 100x better on that same AppleTV using AirPlay and Home Sharing.

5. For supported formats Quicktime is best at playing HEVC on non HEVC hardware. IINA used to be pretty good, VLC has always sucked but Quicktime is by far the smoothest playback.

TL;DR : You can AirPlay 4k assuming the video file formats are compatible and the hardware you are using natively supports handling of that video file and even minor variables can prevent it from working.

 

[priitv8]

From my experience, aTV native player refuses to play UHD@60fps clips. Never worked for me.
Infuse does play also 60fps normally.
What settings did you use on HB to convert from VP9.2 into HDR10?? Did you also include HDR metadata (although they do not seem to be of vital importance).

 

[cynics]

From my experience, aTV native player refuses to play UHD@60fps clips. Never worked for me.
Infuse does play also 60fps normally.
What settings did you use on HB to convert from VP9.2 into HDR10?? Did you also include HDR metadata (although they do not seem to be of vital importance).

Devices : Apple 2160p60 4K HEVC Surround

Encoder : H.265 10-Bit (x265)

Encoder options : Preset : Slow

Everything else was at the defaults for that device and encoder settings.

While the AppleTV 4k still labels it as HDR and its clearly better the actual HDR format (SMPTE ST 2086) doesn't carry over from the VP9.

 

[priitv8]

While the AppleTV 4k still labels it as HDR and its clearly better the actual HDR format (SMPTE ST 2086) doesn't carry over from the VP9.

Yes, you need to give the necessary additional parameters to x265 encoder manually. Enter this text into Additional Options field on Video tab.

uhd-bd:colorprim=bt2020:transfer=smpte2084:colormatrix=bt2020nc:master-display=G(13250,34500)B(7500,3000)R(34000,16000)WP(15635,16450)L(10000000,1):max-cll=1000,400

Values for parameters L and max-cll you should take from the original VP9.2 file.
The magic key that makes all the difference, is the transfer=smpte2084, all others are just garnering.
EDIT: I've actually saved them as my HDR preset in HB.

 

[nicho]

You could also have your own 4K videos taken with iPhone in your iTunes library. I don't see any reason, why they would not play back in native size over Home Sharing or AirPlay.
This picture shows my own movie playing back over Home Sharing (pulled from aTV) from my iTunes library.
I can equally well push it from my iTunes to aTV (AirPlay).
So I am thinking AirPlay does support 4K.

I converted a movie using the handbrake "Apple 2160p60 4K HEVC Surround" profile today, the only change I made was using videotoolbox encoder instead of x265 because I didn't fancy waiting 24h for the results.

It added to the videos app fine, but never appeared in the home sharing library. Is there anything special I need to do to try again and make it work?

 

[priitv8]

It added to the videos app fine, but never appeared in the home sharing library. Is there anything special I need to do to try again and make it work?

Make sure you set the HD Video tag to 1080p and not to 4K, otherwise the movie won't appear on tvOS GUI.