Airplay

[Vincent Kars]

A proprietary protocol for streaming audio/video by Apple.
Initially limited to Apple products only.
Apple has licensed the audio-streaming portion of the AirPlay protocol to others.
From 2011 on streaming audio players appears on the market supporting this protocol.

As Apple talks marketing instead of tech it is almost impossible to find any documentation about the capabilities of this protocol.
Some say it is able of 25 bits / 96kHz.
Most Apple devices like Airport Express are limited to 16/44.1
ATV probably resamples everything to 16/48.

This utter lack of specifications causes a lot of confusion for the users.
An example: Airplay & downsampling.

 

[wgscott]

I have no inside information, but have formed some impressions from using this.

There are two related but distinct mechanisms that can be used.

The first is streaming to an Airport Express or to an ATV. The streaming and playback is controlled by the server computer, via iTunes. In my experience, the connection is anything but robust, and if I try to do this in my bedroom, I get dropouts with frustrating frequency. I'm fairly certain it is this protocol that is implemented in third-party devices like the new Zeppelin, some receivers, etc. If you look at the reviews for those, there are a lot of complaints with how robust the streaming is. Because the steaming qualify is borderline even for compressed audio, it may simply be that 24 bit, 96kHz files are an impossibility using the airplay protocol.

The second mechanism is (for lack of a better word coming to mind) that of a zone-player, via ATV2 and ATV3. iTunes on the server computer essentially behaves as a passive server of music, movies, etc. My experience is listening to music this way, especially when the wireless signal is comparatively weak (like in my bedroom), this is far more robust, since there is a buffering mechanism. The ATV2 also has about 7 gig of SSD "memory", so I imagine that is why it can be used for music and movies. If this latter protocol were to be taken advantage of, I think wireless zone-playing of higher res music would be possible.

I'm almost certain everything is resampled to 48kHz by ATV2, but it might be 24-bit capable. The settings in the interface seem to hint at this (automatic vs. 16 bit). I play it through a 1st gen Zeppelin in my bedroom, which I think only can do 16 bit, 44.1 or 48kHz, so it is not an issue for me. (It sounds fine, given all that resampling, by the way).

 

[Phelonious Ponk]

This utter lack of specifications causes a lot of confusion for the users.

I think it causes a lot of anxiety among audiophiles, most of whom would not use it anyway. Confusion among users? Every user of Airplay I've ever known was just delighted they could push a button and stream whatever was playing on their iPad/Pod to their Apple TV or Airport Express and play their video/audio back on the big system -- just like that. Technology bordering on magic!

Can't say I ever recall a single one of them even asking if it was capable of higher resolution than 16/44.1.

Tim

 

[Vincent Kars]

This reminds me of the “good” old days at CA where there was a guy (also called Tim) who whatever the question about computer based auto was always answered ”get a Mac and press Play”.


Do you really think a manufacturer should present a black box without any specification?
Manufacturer: “Buy our DAC”
Customer: “Can it do 24/96?”
Manufacturer : “It has a deep sound stage”
Customer: “Is the USB input asynchronous?”
Manufacturer : “It sounds analog”

 

[Phelonious Ponk]

This reminds me of the “good” old days at CA where there was a guy (also called Tim) who whatever the question about computer based auto was always answered ”get a Mac and press Play”.


Do you really think a manufacturer should present a black box without any specification?
Manufacturer: “Buy our DAC”
Customer: “Can it do 24/96?”
Manufacturer : “It has a deep sound stage”
Customer: “Is the USB input asynchronous?”
Manufacturer : “It sounds analog”

Only if that manufacturer's customer base doesn't care about audio specs, and just wants to press play.

My point was not that AirPlay, or Apple, is the answer to everything for everybody, but that most of the people for whom it is the answer are neither audiophiles or computer geeks and are typically not interested in specs, just practical performance. You can easily get audiophile quality from apple devices, but thry're not made for audiophiles. If nothing else, the 16/44.1 playback limitation says that loud and clear.

Tim

 

[tonmeister2008]

A proprietary protocol for streaming audio/video by Apple.
Initially limited to Apple products only.
Apple has licensed the audio-streaming portion of the AirPlay protocol to others.
From 2011 on streaming audio players appears on the market supporting this protocol.

As Apple talks marketing instead of tech it is almost impossible to find any documentation about the capabilities of this protocol.
Some say it is able of 25 bits / 96kHz.
Most Apple devices like Airport Express are limited to 16/44.1
ATV probably resamples everything to 16/48.

This utter lack of specifications causes a lot of confusion for the users.
An example: Airplay & downsampling.

I just tried streaming some 24/96k music files from iTunes to my receiver which has AirPlay and confirmed that at the receiver it shows the files as being down-sampeld to 16/44.1kHz. Oh well, another example of convenience over quality, although I doubt I could detect the loss in quality.

 

[amirm]

I managed the team at Microsoft who developed everything to do with audio and video and Microsoft and even I had trouble getting people to do anything that was not mass consumer . Often they would put a feature in just to keep me happy. So it is not surprising to see similar limitations in Apple's version of the same.