Converting MP3-AAC and condensing iTunes library

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Level 1

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Converting MP3-AAC and condensing iTunes library

Picked up an iPad 64GB 3G and decided to put my whole iTunes 40GB library on the device . This has caused me to rethink my bit rates to save some room. I tested MP3 vs. AAC sound quality, I'm a professional musician, and the quality difference was barely noticeable. So here are my questions:

1. Should I convert all of my iTunes files to AAC on both my Macbook Pro and iPad? Does it make a big difference?

2. If I do this, should I put my iTunes library with MP3's on my Time Capsule prior to conversion?

Thanks as always for the advice.

Macbook Pro 2.4Ghz 160GB 4GB, Mac OS X (10.6.3), iPad 64GB 3G, iPhone 3G

Posted on May 23, 2010 7:18 AM

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Answer 1

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Jolly Giant

Level 7

25,464 points

May 23, 2010 8:02 AM in response to MacAddiction

IMHO, it makes little sense to convert from one lossy format into another. if the source files were e.g. Apple Lossless, i would recommend to convert them to AAC 256 (which is superior in quality to MP3 320).

in your case, i would leave things as they are.

happy computing !

J GG

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Answer 2

MacAddiction Author

Level 1

8 points

May 23, 2010 8:09 AM in response to Jolly Giant

Thanks Jolly. I guess the bottom line is that I don't fully comprehend all the various formats.

Most of mine are MPEG, 225 kbps (VBR).

I noticed that I have quite a few AIFF files that are huge. When I converted a sample MPEG to AAC, it saved a good bit of space.

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Answer 3

Jolly Giant

Level 7

25,464 points

May 23, 2010 8:41 AM in response to MacAddiction

MacAddiction wrote:
I guess the bottom line is that I don't fully comprehend all the various formats.

see Digital Audio Formats: A Guide

Most of mine are MPEG, 225 kbps (VBR).

as i said, i would leave them as they are.

I noticed that I have quite a few AIFF files that are huge.

AIFF is a lossless format (as the article above outlines). here it would sense to convert to, say, AAC 256.

edit the article does not mention AIFF so here's a read to peruse: http://en.wikipedia.org/wiki/AudioInterchange_FileFormat

When I converted a sample MPEG to AAC, it saved a good bit of space.

true. but, converting from an already lossy format to an even lossier (e.g. AAC 128) will certainly affect the sound quality. so, it comes down to what is more important to you: space or sound quality. since you are a professional musician, i would expect the latter 😉

what i'm doing is this: CD's are ripped into Apple Lossless files. i move these files to an external HD, then option drag them into iTunes. this will cause iTunes to index the path to the original files but not copy them physically into my main library. with the external connected, i have iTunes convert the Apple Lossless into AAC 256. the AAC's are added to the main library.

for example, if an Apple Lossless files weighs in @ 34,2 MB, the AAC 256 has 9,2 MB only but the sound quality is excellent.

J GG

edited by the Jolly Green Giant (where Green stands for environmentally friendly)

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Answer 4

MacAddiction Author

Level 1

8 points

May 23, 2010 9:06 AM in response to Jolly Giant

Thanks JGG! That makes perfect sense now that I understand formats (thanks to your link).

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Answer 5

Jolly Giant

Level 7

25,464 points

May 23, 2010 9:09 AM in response to MacAddiction

glad i could help !

enjoy ...

J GG

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Answer 6

Chris CA

Level 10

82,440 points

May 23, 2010 9:14 AM in response to MacAddiction

When I converted a sample MPEG to AAC, it saved a good bit of space.

Because you converted to a lesser bit rate, not because you converted from MPEG to AAC.
You would have also saved space had you converted to lesser bit rate AAC.
And as Jolly stated, not a great idea to convert from one lossy format to another unless you really, really need to.
Also, if you want to change bit rates (say shrink file size), it's best to reRIP from the highest quality source (ie. CD) you have.

(FYI: MPEG audio file in iTunes is MP3)

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