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Re: Re: latest iPod firmware can record via mic

Subject: Re: Re: latest iPod firmware can record via mic
From: Walter Knapp <>
Date: Mon, 20 Oct 2003 20:45:40 -0400
oryoki2000 wrote:

> Walter Knapp wrote:
>  
> 
>>iPod Audio formats supported
>>AAC (up to 320 Kbps), MP3 (up to 320 Kbps), 
>>MP3 Variable Bit Rate (VBR), WAV, AIFF(Mac only), Audible
> 
> 
> Oops!  So Mac users can play AIFF files on their iPods. That'll teach 
> me to scroll down and read the whole page before forming a 
> conclusion.  

It would be really, really strange for Apple to put out iPods with no 
native AIFF.

I've not played with my wife's iPod in a while. When she first got it my 
machine was the only one here that could load it, so I got to play a bit 
back then. AIFF played back then, so is not something connected with the 
current firmware update. I think the firmware is more that you can 
record a audio signal than what format. With the right software I expect 
any format it can use will work. Belkin, for their own reasons choose 
mp3 and WAV. But let's not assume that's a limitation. It would be 
interesting to use AAC, for instance.

> It will be interesting to see if the AAC format, which is part of the 
> MPEG4 specification and is incorporated into Quicktime, can make 
> progress against the overwhelming popularity of MPEG1 level 3 (MP3) 
> format.  AAC encoding produces similar sound quality to MP3, but from 
> a file that's as much as 25% smaller.  Since it's often a challenge 
> to squeeze a movie onto a single DVD disc, AAC's smaller file size is 
> an important advantage.

Actually, MPEG4 is Quicktime, they just adopted Quicktime as the new 
standard and renamed it. Kind of handy for mac users for once.

Audio is being driven largely by video now. So I expect with time that 
AAC, which is the official one will take over.

Remember, there is quicktime for windows as well. For those windows 
folks that want to play with it.

I've got the software for it, but have been holding off messing with it 
much to see if it get's going. Once it does I'll convert my website to 
it. Quite a few places have implemented locks against mp3's on their 
internet access. My mp3's are not at all connected with music, but get 
caught in the same net. Even my wife cannot access our own frog pages at 
work.

> Regarding the reverse byte order of WAV versus AIFF, the root of this 
> difference is that the Motorola processors in Macintosh computers put 
> the most significant bytes in the lower memory locations (so-called 
> big-endian byte order), while Intel processors in PCs are little-
> endian.  This is of no practical consequence since all CD writing 
> programs make the appropriate adjustments without any user 
> intervention other than to specify you want an "audio CD."

Not just Motorola, big-endian is standard on the various unix machines 
too. Has been so as far back as I can remember, so I'm pretty sure 
Motorola copied either mainframes or unix. Intel went off by themselves. 
Along with some other oddball stuff still haunting windows.

In all my software I can switch back and forth between WAV and AIFF 
storage. It does take processing time to do it. Since there is little 
other different, I've always assumed that the conversion of bit order is 
the source of the extra time. File size also shifts by a percent or so.

I'd also like to see a closer look at the sound intensity correspondence 
between the two. Sound is not a straight line set of values. Matching 
curves may be what's taking the effort by my editing software. I have 
heard .wav files that sounded different than the CD recorded by others. 
I don't, as a routine record audio CDs from .wav, but convert them to 
aiff first. I would not assume just because it's automatic and does not 
have to be specified that it does nothing. And, it's certainly a extra 
processing step in the software.

Walt




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