[iOliverC]

In iTunes, my library is full of both aac and mp3 files. What I would like to do is convert all the mp3 files to aac and delete all the mp3's. Converting ALL the library would take ages and would just waste time. Is there any app that can do this? Or can iTunes do it built in?

[Turias]

Well, you could create a smart playlist that only holds mp3s...

But why would you ever want to take an mp3 and encode it as an aac? You would lose a ton of quality and gain no disk space.

[iOliverC]

Originally posted by Turias:
Well, you could create a smart playlist that only holds mp3s...

But why would you ever want to take an mp3 and encode it as an aac? You would lose a ton of quality and gain no disk space.

Are you sure? I converted a 5.4mb mp3 to a 128k aac and it ended up at 3.2mb. And I couldn't tell the sound quality.

[Turias]

Originally posted by iOliverC:
Are you sure? I converted a 5.4mb mp3 to a 128k aac and it ended up at 3.2mb. And I couldn't tell the sound quality.

well, if you have a 256kbps mp3 and encode it as a 128kbps aac, you will gain about half your disk space back. A 128kbps mp3 to a 128kbps aac will save no space.

The thing is, this technique will _always_ result in lower quality music files. A 128kbps aac ripped from CD will sound a hell of a lot better than a 128kbps aac encoded from an mp3.

Basically, you lose quality each time you encode something with a codec such as mp3, aac, wma, ogg, etc.

If I were you, I would instead rip the aacs from CD and leave any mp3s you don't have the cds for as they are.

[Spheric Harlot]

Originally posted by iOliverC:
Are you sure? I converted a 5.4mb mp3 to a 128k aac and it ended up at 3.2mb. And I couldn't tell the sound quality.

The point is, in a drastically simplified nutshell version, that these compression algorithms work not just by squeezing data down, but by actually REMOVING audio information (based on psychoacoustic theories and phenomena).

AAC does the same, but uses a different algorithm which uses a different method, removing different data.

aac will sound better than mp3 at equal bitrates when run on the same source, but converting mp3s to aac *will* heavily deteriorate sound quality.

Think of it as mp3 being a black and white Xerox copy of a painting and aac being a color copy of the painting. Neither will look as good as the original, but a color copy of the black and white Xerox will look even worse than the Xerox.

A color copy of the original, however, will look a lot better than the black and white Xerox copy.

-s*

[Turias]

Heh. Gotta remember that analogy...

[Fothb]

My favorite tool for converting from MP3 to AAC is called "AAChoo" by Ovolab. I use it for encoding my AIFFs to AAC as well. If you mess with the quality settings, you end up with a lot better sounding AAC file than you would if you let iTunes do the encoding.

AAChoo has an option to skip over existing AAC (.mp4) files, so it sounds like it would be perfect for you. If you drag a folder over that has 100 MP3s and 100 AACs, it will only conver the MP3s and the AACs will be completely left alone.

[mrchin]

Tto the original question of converting the MP3 easily...

In your iTunes edit menu, go to View Options and check Kind as a viewable column. Then,when you're at your Library level, select the Kind column by clicking on the label at the top of the column. This will sort your songs by kind. (alphabetically) All you need to do is scroll down to MP3s and they'll all be in one spot. Just highlight them all and convert to AAC. Once complete, delete the original MP3s.

Sorry for the simple explanations as I don't know how experienced you are. This may also help anyone who is more novice. But thatt should be the easiest way without having to create playlists, etc.

[iOliverC]

Thanks all,

In the end (before I saw mrchin's reply) I emptied my library so it was empty, went into my Music folder and searched for mp3, I then dragged those mp3's into the Library and converted them into aac's. Worked a charm.