iPod MP4 Players?

Shrek

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Original poster
Jul 23, 2002
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Nashville, Tennessee USA
http://www.apple.com/mpeg4/aac/

MPEG-4 AUDIO: AAC

Because of its exceptional performance and quality, Advanced Audio Coding (AAC) is at the core of the MPEG-4 specification and is the new audio codec of choice for Internet, wireless, and digital broadcast arenas. AAC provides audio encoding that compresses much more efficiently than older formats such as MP3, yet delivers quality rivaling that of uncompressed CD audio.

AAC was developed by the MPEG group that includes Dolby, Fraunhofer (FhG), AT&T, Sony, and Nokia—companies that have also been involved in the development of audio codecs such as MP3 and AC3 (also known as Dolby Digital). The AAC codec in QuickTime 6 builds upon new, state-of-the art signal processing technology from Dolby Laboratories and brings true variable bit rate (VBR) audio encoding to QuickTime.

Move Over MP3
Internet audio has become wildly popular in recent years, specifically in the MP3 format. But what most listeners don’t realize is that MP3’s compression technology is more than a decade old. In those ten years, many advances in perceptual audio coding and compression have been achieved. AAC takes full advantage of these advances, resulting in higher quality output at lower data rates, allowing even modem users to hear a difference.

When compared side-by-side, AAC proves itself worthy of replacing MP3 as the new Internet audio standard. Take a look at these AAC advantages over MP3:
Improved compression provides higher-quality results with smaller file sizes
Support for multichannel audio, providing up to 48 full frequency channels
Higher resolution audio, yielding sampling rates up to 96 kHz
Improved decoding efficiency, requiring less processing power for decode

The Data Speaks for Itself
In numerous comparison tests, AAC comes out on top. Check out these impressive results:
AAC compressed audio at 128 kbps (stereo) has been judged by expert listeners to be “indistinguishable” from the original uncompressed audio source.*
AAC compressed audio at 96 kbps generally exceeded the quality of MP3 compressed audio at 128 kbps. AAC at 128 kbps provides significantly superior performance than does MP3 at 128 kbps.*
AAC was the only Internet audio codec evaluated in the range “Excellent” at 64 kbps for all of the audio items tested in EBU listening tests.*

* See the AAC website for reference.

Why Wait?
With the release of QuickTime 6, the newest-generation technology for digital audio is now widely available – AAC audio in MPEG-4. Hear the quality for yourself in our MPEG-4 (AAC) Audio Gallery.
Does this mean that iPod MP4 Players could be on the way? I CERTAINLY HOPE SO!!! :D MP4 Players could bring the same audio quality that MP3 gave us, but at a much lower bit rate, boosting the overall number of songs we can store on our portable players. Or it could be used to maximize the sound quality of our music by giving us higher quality sound (than MP3), but at the same or higher bit rates resulting in true Dolby Digital/THX/Surround Sound!!! :eek: Neato! :D
 

TyleRomeo

macrumors 6502a
Mar 22, 2002
888
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New York
Re: iPod MP4 Players?

Originally posted by Shrek
http://www.apple.com/mpeg4/aac/



Does this mean that iPod MP4 Players could be on the way? I CERTAINLY HOPE SO!!! :D MP4 Players could bring the same audio quality that MP3 gave us, but at a much lower bit rate, boosting the overall number of songs we can store on our portable players. Or it could be used to maximize the sound quality of our music by giving us higher quality sound (than MP3), but at the same or higher bit rates resulting in true Dolby Digital/THX/Surround Sound!!! :eek: Neato! :D
Yes Shrek, you are correct. Since iPods use hard drives and have firmware updates, they will eventually support AAC Audio. I'm guessing once iTunes has better support for AAC Audio, with complete and correct ID tags, which iPod basically runs on.

tyler
 

Quark

macrumors regular
Jan 9, 2002
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Not so fast

I have heard this discussed before, and someone made a point about the Codec chip being designed to handle certain compressed data, but (as I recall) they said that it couldn't handle AAC.

I have an iPod and hope that it is just a firmware update, but something tells me that it will be more than that.

Quark
 

zarathustra

macrumors 6502a
Jul 16, 2002
770
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Philadelphia, PA
Re: Not so fast

Originally posted by Quark
I have heard this discussed before, and someone made a point about the Codec chip being designed to handle certain compressed data, but (as I recall) they said that it couldn't handle AAC.

I have an iPod and hope that it is just a firmware update, but something tells me that it will be more than that.

Quark
Good call. As I recall the chip in charge of decoding MP3 data was able to encode MP3s, but I wonder if that's as far as it will go.

Since I am not an übergeek (meant in a complimentary way) I would think that it would be more likely that you could use the firewire port to connect to the next generation of Hi-Fi audio systems (such as Panasonic's new entertainment system that uses a single FireWire cable to connect various components) and encode/download audio from there.

What algorithms and calculations go into an AAC file is beyond me, but feel that it would be too complex, but then again I like being suprised.
 

drastik

macrumors 6502a
Apr 10, 2002
978
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Nashvegas
Maybe I misunderstood the above posts, but as far as I know, the iPod itself doesn't do any encoding. My powermac can certianly encode AAC, and in fact, I've been reripping CDs for a couple of days now. I should think it will only be a firmware upgrade to the iPod, I can't imagine any needed hardware change.
 

jelloshotsrule

macrumors G3
Feb 7, 2002
9,591
3
serendipity
only thing that keeps me from believing it's a hardware thing, not a firmware thing, is that apple was well into aac research and use or whatever when they released the ipod. they had to see it coming


i thought that the current delay in not being able to use aac as a purely audio file was a licensing issue....

therefore, who knows when we'll see the firmware, and an update to itunes to encode with it...
 

TyleRomeo

macrumors 6502a
Mar 22, 2002
888
0
New York
Originally posted by jelloshotsrule
only thing that keeps me from believing it's a hardware thing, not a firmware thing, is that apple was well into aac research and use or whatever when they released the ipod. they had to see it coming


i thought that the current delay in not being able to use aac as a purely audio file was a licensing issue....

therefore, who knows when we'll see the firmware, and an update to itunes to encode with it...
bulls-eye!!!!!!!!!!

the iPod is nothing more than a toshiba HD and apple's iTunes software and little extras. if quicktime can do AAC, then iTunes can do AAC and soon iPod will do AAC. just wait for the firmware

tyler
 

peterjhill

macrumors 65816
Apr 25, 2002
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Seattle, WA
The iPods are on sale at the computer store at the university where I work. I just ordered a 10 GB iPod for $319. The 5 GB is $219 and the 20GB is $419. This is an awesome deal. Check to see if you local universities have the same deal and make friends with a student or staff member. ;-)
 

jelloshotsrule

macrumors G3
Feb 7, 2002
9,591
3
serendipity
Originally posted by TyleRomeo


bulls-eye!!!!!!!!!!

the iPod is nothing more than a toshiba HD and apple's iTunes software and little extras. if quicktime can do AAC, then iTunes can do AAC and soon iPod will do AAC. just wait for the firmware

tyler
whoa, i got something right. phat... ha

and apparently the mp3 patent owners are now charging for both encoders AND decoders... will that affect itunes/ipod at all i wonder? hmm

clicky
 

FelixDerKater

macrumors 68030
Apr 12, 2002
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Nirgendwo in Amerika
iPod...

Does the iPod not run off dual StrongARM chips? Have I been lied to? If it does run off these chips, then they are not made specifically for anyt type of decoding, but are used for it, just as the G4 in my TiBook does decoding of MP3 among many other things. Therefore, the software is all we need, not a replacement iPod or anything like that.
 

FelixDerKater

macrumors 68030
Apr 12, 2002
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Nirgendwo in Amerika
Addition to last post...

Another valid question would be whether the chips are powerful enough to decode MP4. Since I am not very familiar with the codec I am unaware as to how much more processor intensive it is.

Also, even if the current iPods are capable of running MP4/AAC Audio, through a simple software update, Apple still may decide to only offer it on new iPods.
 

jelloshotsrule

macrumors G3
Feb 7, 2002
9,591
3
serendipity
Re: Addition to last post...

Originally posted by FelixDerKater
Also, even if the current iPods are capable of running MP4/AAC Audio, through a simple software update, Apple still may decide to only offer it on new iPods.
i don't see that happening

if it does, there will be more furious people

it would be another way of apple screwing people who buy their stuff early on... ie, early supporters... then being screwed for not waiting

i think we've seen enough of that for a bit
 

dongmin

macrumors 68000
Jan 3, 2002
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hardware issues

I'm not sure what you guys are saying about the iPod's hardware capabilities is totally accurate. According this DesignChain.com article, iPod actually has a dedicated mp3 decoder chip:

The rest of the device uses a dedicated MP3 decoder and controller chip from PortalPlayer, a Wolfson Microelectronics Ltd. stereo digital-to-analog converter, a flash memory chip from Sharp Electronics Corp., a Texas Instruments 1394 firewire interface controller, and a power management and battery charging IC from Linear Technologies Inc.

Also from Anandtech.com:

The final noteworthy item on the iPod's PCB actually turns out to be the unit's CPU. The chip is a PP5002B-C chip made by PortalPlayer. Although the specifications of the version of the chip used in the iPod are not available on PortyalPlayer's website, specifications on their P5001 controller are available. Bearing the similar product names, we can speculate that not much has changed in the Apple specific chip. If this is in fact the case, then the PP5002B chip has a ARM7 TDMI based core with a coprocessor dedicated to real time encoding acceleration. The processor is able to not only decode MP3 and wma files (note that the iPod's chip can decode MP3 files up to 320 Kbps, MP3 variable bit rate, WAV, and AIFF files), it is also able to encode on the fly (a feature which Apple did not take advantage of in the iPod). The chip also features an integrated 32KB of SRAM and 8KB of cache. We are unsure of the operating frequency of the chip or how many MIPS the chip can handle, but the iPod never functioned slowly suggesting that there is plenty of power.


So maybe AAC is not so easy an addition to make...
 

peterjhill

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Apr 25, 2002
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Seattle, WA
Re: hardware issues

Originally posted by dongmin

We are unsure of the operating frequency of the chip or how many MIPS the chip can handle, but the iPod never functioned slowly suggesting that there is plenty of power.


So maybe AAC is not so easy an addition to make...
It probably depends on one of two things. Can the processor handle the decoding? Can the current hardware decoder be used to help decode the AAC files?

I hope support does come for mpeg4, but now that I have ripped my entire 4200+ song cd collection, I will not rerip for mpeg 4. If support comes out, new cds I purchase will go into mpeg4. Maybe some favorite CDs.