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Matt Wagner
2004-06-07, 14:29
....
For those wondering if AirPort Express supports MP3, AAC, or any other
specific file formats, the answer is no. AirPort Express supports Apple's
Lossless Compression technology -- and everything that your iTunes
streams across the network to Airport Express is compressed using that
technology.

iTunes does the heavy lifting. When iTunes plays back standard audio
content (AAC, MP3, audiobooks, music streams), it decompresses those file
formats and creates what's essentially a raw, uncompressed audio stream.
That stream is compressed on the fly using Apple's Lossless Compression,
encrypted, and sent to the AirPort Express. AirPort Express decrypts the
stream, decodes it, and outputs it in either analog format (if you plug
in a standard analog mini jack) or as a digital PCM stream (if you plug
in a mini-sized optical cable, which you can get from most major cable
suppliers or straight from Apple for $39).
....


http://www.macworld.com/weblogs/editors/archives/000212.php

How AirTunes Works

I spent a little bit of time with Greg Joswiak, Apple's Vice President of
Hardware Product Marketing, talking about how the new AirPort Express works,
especially the new AirTunes audio features.

Essentially, AirTunes is a method of creating remote speakers for a copy of
iTunes, and sending data to those remote speakers via a wireless network.
That network can be formed by connecting an AirPort Express to another
AirPort Express, to an AirPort Extreme Base Station, or even to a non-apple
802.11b or 802.11g access point.

When you select an AirPort Express device in the new pop-up menu at the
bottom of the iTunes 4.6 interface, that device essentially replaces your
Mac's speakers as the audio-output source for whatever you do in iTunes. At
that point you can do anything you'd normally do in iTunes -- play music
from your Library, from someone else's library, or from your iPod; play an
Internet radio stream; even play an audiobook. The sound won't come out of
your Mac -- it'll come out of the speakers attached to the AirPort Express.

For those wondering if AirPort Express supports MP3, AAC, or any other
specific file formats, the answer is no. AirPort Express supports Apple's
Lossless Compression technology -- and everything that your iTunes streams
across the network to Airport Express is compressed using that technology.

iTunes does the heavy lifting. When iTunes plays back standard audio content
(AAC, MP3, audiobooks, music streams), it decompresses those file formats
and creates what's essentially a raw, uncompressed audio stream. That stream
is compressed on the fly using Apple's Lossless Compression, encrypted, and
sent to the AirPort Express. AirPort Express decrypts the stream, decodes
it, and outputs it in either analog format (if you plug in a standard analog
mini jack) or as a digital PCM stream (if you plug in a mini-sized optical
cable, which you can get from most major cable suppliers or straight from
Apple for $39).

If iTunes is playing back a digital multichannel file format like AC3 (Dolby
Digital) or DTS, those bitstreams are wrapped in Apple's compression and
encryption, and then decoded at the other end. In those cases, AirPort
Express would end up streaming the raw AC3 or DTS stream via an optical
cable to your home theater receiver for decoding.

This means that if you're currently listening to music on speakers attached
to your Mac, AirPort Express doesn't change the Mac side of the experience
at all: you're still using iTunes as your musical interface, and you've got
to keep that Mac on and iTunes open in order to keep the music playing. (As
opposed to a device like Slim Devices' Squeezebox, [4 mice, April 2004],
which is operated by an infrared remote control and has its own display to
show you what's playing and let you change what you're listening to.) You
can also only play one thing at a time, and to only one set of speakers. But
now those speakers can be just about anywhere.

Apple's not ruling out taking those sorts of approaches -- Joswiak himself
agreed that some sort of remote-control device would be a cool addition to
AirPort Express. But as Joswiak put it to me, this is a first step for Apple
in getting iTunes music into another part of your life -- in this case, into
places where there are no computers or iPods.

Jason Snell
2004-06-07, 22:59
Matt Wagner wrote:

> For those wondering if AirPort Express supports MP3, AAC, or any other
> specific file formats, the answer is no. AirPort Express supports Apple's
> Lossless Compression technology -- and everything that your iTunes
> streams across the network to Airport Express is compressed using that
> technology.

There is nothing weirder than having yourself quoted back to you on a
mailing list. :-)

-jason
--
Jason Snell / Editor in Chief, Macworld / jsnell (AT) macworld (DOT) com
415-243-3565 / AIM-iChat: MW jsnell

Dave Scott
2004-06-08, 00:31
On 8 Jun 2004, at 13:59, Jason Snell wrote:

> Matt Wagner wrote:
>
>
> There is nothing weirder than having yourself quoted back to you on a
> mailing list. :-)
>
> -jason
> --
> Jason Snell / Editor in Chief, Macworld / jsnell (AT) macworld (DOT) com
> 415-243-3565 / AIM-iChat: MW jsnell
>
Jason - while slightly off topic

Do you have any idea if Airport Express can co-exist with existing
Airport Network (Snow Base Station) as in a separate network (ie
Airport Express closed, not connected to Internet, more as a wireless
hub)

Thinking along these lines -

Slimp3 uses main Airport Network in my lounge - which is also main
gateway to Internet...

Airport Express in my bed room connected to a set of powered speakers ..

Slimp3 doing its thing, & the Airport Express streaming iTunes into the
bedroom.

Cannot see an issue with Powerbook side of things but not sure if
Airport card can talk to two separate Airport stations

Curious - if works great - if not, guess time to upgrade to an Airport
Extreme Base station or two Airport Expresses

Cheers

Dave Scott

Michael Hecht
2004-06-08, 05:55
On Jun 7, 2004, at 5:29 PM, Matt Wagner wrote:

> ...
> For those wondering if AirPort Express supports MP3, AAC, or any
> other
> specific file formats, the answer is no. AirPort Express supports
> Apple's
> Lossless Compression technology -- and everything that your iTunes
> streams across the network to Airport Express is compressed using
> that
> technology.
>
> iTunes does the heavy lifting. When iTunes plays back standard audio
> content (AAC, MP3, audiobooks, music streams), it decompresses
> those file
> formats and creates what's essentially a raw, uncompressed audio
> stream.
> That stream is compressed on the fly using Apple's Lossless
> Compression,
> encrypted, and sent to the AirPort Express. AirPort Express
> decrypts the
> stream, decodes it, and outputs it in either analog format (if you
> plug
> in a standard analog mini jack) or as a digital PCM stream (if you
> plug
> in a mini-sized optical cable, which you can get from most major
> cable
> suppliers or straight from Apple for $39).
> ...

So...

How hard would it be to enable iTunes 4.6 to select my SliMP3 as its
"remote speakers" -- basically have iTunes stream directly to the
SliMP3 -- as a means to let me play protected AAC files there?

Maybe iTunes -> SlimServer -> SliMP3 for playback? And I'm sure the
SlimServer could be taught to control iTunes in the other direction
(ie: to select a song from the remote).

--Michael

--
Michael P. Hecht -- michael.hecht (AT) jmp (DOT) com
JMP, a Business Unit of SAS Institute -- http://www.jmp.com/

Jason Snell
2004-06-09, 16:25
>Do you have any idea if Airport Express can co-exist with existing
>Airport Network (Snow Base Station) as in a separate network (ie
>Airport Express closed, not connected to Internet, more as a
>wireless hub)

sure, they should co-exist fine. but your Mac can only connect to one
at a time.

>Thinking along these lines -
>
>Slimp3 uses main Airport Network in my lounge - which is also main
>gateway to Internet...
>
>Airport Express in my bed room connected to a set of powered speakers ..
>
>Slimp3 doing its thing, & the Airport Express streaming iTunes into
>the bedroom.

to make this work you'd need to connect AirPort Express wirelessly to
the main AirPort network, so that your Mac running iTunes could also
see it.


--
Jason Snell / Editor in Chief, Macworld / jsnell (AT) macworld (DOT) com
415-243-3565 / AIM-iChat: MW jsnell

Jason Snell
2004-06-09, 16:26
>How hard would it be to enable iTunes 4.6 to select my SliMP3 as its
>"remote speakers" -- basically have iTunes stream directly to the
>SliMP3 -- as a means to let me play protected AAC files there?

Really hard, because what's being sent by iTunes is a stream that's
encrypted (specifically for the AirPort Express) and in Apple
Lossless format, which SLIMP3 doesn't support.

-jason


--
Jason Snell / Editor in Chief, Macworld / jsnell (AT) macworld (DOT) com
415-243-3565 / AIM-iChat: MW jsnell

Michael Hecht
2004-06-10, 12:21
On Jun 9, 2004, at 7:26 PM, Jason Snell wrote:

>> How hard would it be to enable iTunes 4.6 to select my SliMP3 as its
>> "remote speakers" -- basically have iTunes stream directly to the
>> SliMP3 -- as a means to let me play protected AAC files there?
>
> Really hard, because what's being sent by iTunes is a stream that's
> encrypted (specifically for the AirPort Express) and in Apple Lossless
> format, which SLIMP3 doesn't support.

Sorry, I missed the part about it being encrypted. The encryption makes
it no better than the current situation with protected AAC. Oh well...

In theory, the Apple Lossless could be transcoded back to MP3 (which
happens now on the SlimServer end). After a while though, all that
transcoding has got to wear you down.

--Michael

--
Michael P. Hecht -- michael.hecht (AT) jmp (DOT) com
JMP, a Business Unit of SAS Institute -- http://www.jmp.com/