Airplay 2 details

[chekk]

The "Introducing Airplay 2" talk for developers has been posted and can be watched from the WWDC App, or here: https://developer.apple.com/videos/play/wwdc2017/509/ (~40 min long)

I just watched it, and am posting the highlights below. [Comments in square brackets are from me]

Interesting take-homes:
-3rd-party apps may need to be updated to opt in to Airplay 2 features.
-Airplay 2 receivers need more memory [which will likely limit upgradeability]
-Nothing today about multi-room audio or UI. Multi-room not included in the current beta.


Intro:
-You can still wirelessly send your app's content to an Airplay (1) Speaker
-You can also send it to multiple Airplay 2 speakers, with "very tight sync"
-We've enhanced audio buffering on the Airplay 2 speakers
-Multi-device control: multiple Apple devices can interact with audio streamed throughout the house

Airplay 2 will work from iOS, tvOS, and macOS.

Supported speakers:
-HomePod
-"latest generation" of AppleTV
-Future devices that will be coming to market
-(No mention of upgrades for existing Airplay clients, including Airport Express)

Other devices on the network will be able to send remote commands back to the source app (pause, etc.)
Metadata about the currently playing info will be available to other devices

Deeper look at Airplay buffer levels:
Airplay today:
-real-time stream, "to which the speaker adds just a few seconds of buffering"
-but we can do better if we have long-form audio

Airplay 2 "enhanced buffering":
-we've added very large buffer capacity on the Airplay 2 speakers; "minutes not seconds"
-can stream audio from app to speaker faster than real-time

More robust: larger buffer can survive network glitches like dead spots, microwaving popcorn (!)
More responsive: latency to respond is not linked to buffer level. Play/pause/skip should be instantaneous. [Audio startup should be faster too]

More stuff:
Audio formats supported? All platform formats supported from within app (LPCM, AAC, mp3, ALAC Lossless, lots of samplerates and bit depths) [not stated what format is used for transmission to speakers, Airplay 1 reportedly used ALAC (lossless) at 16-bit, 44.1kHz ].

Video synchronization: you can sync up Airplay 2 audio to your in-app video (NB: this is not referring to Airplay of Video)

Availability:
-"Happy to say" everything discussed is in today's Beta. Toggle "Airplay 2" in the developer panel, and use an updated Apple TV as the receiver.
-Multiroom audio will be available in a future Beta

 

[Applestock]

I wish they included Airplay one in the multiroom audio game. I don't need super tight sync between my upstairs and downstairs airplay speakers; I'm perfectly happy with how they stream together with Airplay 1 through a Mac. Airplay 2 should be about faster play start, better buffer, and audio sync for same room streaming.

 

[Julien]

Does "Future

I wish they included Airplay one in the multiroom audio game. I don't need super tight sync between my upstairs and downstairs airplay speakers; I'm perfectly happy with how they stream together with Airplay 1 through a Mac. Airplay 2 should be about faster play start, better buffer, and audio sync for same room streaming.

Keep in mind that AirPlay 2 will allow you to setup multiple speakers (like stereo and probably 5.1 and more) in the same room. Any latency would ruin this setup.

 

[Applestock]

Does "Future

Keep in mind that AirPlay 2 will allow you to setup multiple speakers (like stereo and probably 5.1 and more) in the same room. Any latency would ruin this setup.

And yet it's possible from iTunes on macOS. This feels like a play to sell more speakers/homepods.

 

[brilliantthings]

I'd love to know if they are going to break support for Airfoil's Airplay 1 iOS multiroom audio in High Sierra. Any word on this?

 

[hevaKmaI]

IMHO, they have to at least meet (if not beat) what the Chromecast Audio can do, and given the CCA is only $35, that’s a high bar:

- multi room audio that can be synced, CCA allows for the adjustment of delay for each target to perfectly synchronize audio
- app support across many platforms, CCA actually has broad support across most iOS apps and all Android apps
- optical bitstream out, yes, CCA has a mini toslink output that supports even 24bit flac (through plex), and allows you to hook up to a home theater receiver and use the receiver’s DAC....for $35!

I didn’t even see anything about an analogue to a Chromecast Audio that would allow you to use your existing speakers with AirPlay 2. This is a non-starter. I don’t want to be forced to by “AirPlay” speakers. I want to buy good speakers that I can hook up to any device I wish. How can you have multi room audio throughout your home and not include your home theater system in that?

I had hopes Apple had come to their senses about AirPlay and would play to win, but it doesn’t seem like it with what’s been shown so far. It’s almost like the people making these decisions at Apple have their head in the sand when it comes to seeing/trying what’s already out there.

 

[LinkTree]

How can you have multi room audio throughout your home and not include your home theater system in that?

But you can - since Apple TV 4 works as an AirPlay2 you should hook up the HT system to that...
[doublepost=1497344362][/doublepost]Does anyone knows what the implementation is?
Meaning - does it works the same way as CC or Spotify? Where you basically gives the device a stream URL and it handles it from there?

Since currently the iPhone does the streaming its takes a lot of resources on the phone and if the phone looses connectivity you loose the stream.

 

[Julien]

And yet it's possible from iTunes on macOS. This feels like a play to sell more speakers/homepods.

How do you adjust latency in AirPlay to under 100ms? I have an AirPort Express upstairs and when walking up/or down I often hear timing differences closer to 500ms. They are usually close but in implementing stereo or 5.1 with proper imaging requires small tolerances in latency. Even latency as small as 100ms can "move" the speaker's perceived sound image in relation to other speakers by about 10'. While 100ms to 200ms may be OK for walking around or close rooms it is unacceptable to seated "sweet spot" listening and could not pass a calibration.

 

[hevaKmaI]

But you can - since Apple TV 4 works as an AirPlay2 you should hook up the HT system to that...
[doublepost=1497344362][/doublepost]Does anyone knows what the implementation is?
Meaning - does it works the same way as CC or Spotify? Where you basically gives the device a stream URL and it handles it from there?

Since currently the iPhone does the streaming its takes a lot of resources on the phone and if the phone looses connectivity you loose the stream.

I didn’t consider the Apple TV 4, but in all honesty, that device was obsolete the day it came out so it wasn’t even a consideration. Here we are a little over a year later and still no 4K or HDR support. It also costs $150, which is more than a simple airplay target should. An NVidia Shield gives you an order of magnitude more for your money than an Apple TV.

 

[oneMadRssn]

I'm still unclear as to which device actually acts as the server and client with AirPlay 2.

With AirPlay 1, the user device (iphone/mac) acts as both a client and server. It is a client in terms of receiving audio from an app, and it is a server in terms of serving that audio to an AirPlay device. The AirPlay device was a client in that it received the audio from the user device. This caused issues because there are two steps between app and airplay device. It goes app>userdevice>airplaydevice. If there was a connectivity issue in any of those steps, the audio wouldn't work.

Chromecast and Sonos and the like work differently. The user device is merely a remote, and the Chomecast/Sonos device act as the client to the app directly. The user device merely passes a URL to the Chromecast/Sonos, and the Chromecast/Sonos connects directly to the app's server to receive the stream. The connection is simpler: app>speaker. Thus if the user device goes totally off-line, the audio is not interrupted.

Which one of these two schemes is AirPlay 2? If it's still the former, then it will still be buggy when someone with the phone playing the audio wanders away from the WiFi signal for a long time. If it's the latter, then it will be great but I doubt any AirPlay1 devices will be upgraded.

 

[chekk]

Does anyone knows what the implementation is?
Meaning - does it works the same way as CC or Spotify? Where you basically gives the device a stream URL and it handles it from there?

Since currently the iPhone does the streaming its takes a lot of resources on the phone and if the phone looses connectivity you loose the stream.

The developer video made it clear that the Airplay 2 speaker does not directly download media from the internet. Instead, just as in Airplay 1, all the logic (managing the audio stream, etc) lives on a single source device (which can be an iOS, tvOS, or macOS device).

In order to get the nice functionality of the Chromecast (where multiple devices can interact with the speaker as if it was independent), they implement a system where other devices send messages back to the source device.

In order to get over the problem of network dropouts, they have increased the buffer size to 'minutes' (and then they deal with the complications involved there--source can fill the buffer at faster than real-time; the source device can invalidate the cache if needed)