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iTunes AAC...converting question

mnkeybsness

mnkeybsness

macrumors 68030
Original poster
Jun 25, 2001
2,511
0
Moneyapolis, Minnesota
i searched and never really found a straight answer...

is it worth my while to encode all of my MP3s which have higher than 128bit compression into AAC? i have all the way up to 320bit mp3 files...quite a few...i'm not so worried about the converting time...

thoughts? comments? answers?
 
it's my understanding that it is not a good idea to encode AAC from MP3. encoding one lossy compression into another lossy compression will probably result in crappy sound (even at high bitrates). if you have original CDs, it is preferable to encode AAC files from an uncompressed CD.

however, i haven't actually tried it - so maybe you should try a few files and compare them to the MP3s you encoded from and see if you mind the difference. i'd actually be curious (not that i think i'd do it anyway).
 
Time

I converted a song I had from 256kbps to AAC 128kbps. It sounded a little...degrarded (i guess the word would be), but nothing THAT noticable. It also takes longer to convert one song then it does to rip it off a CD.
 
Re: Time

Originally posted by MacAztec
I converted a song I had from 256kbps to AAC 128kbps. It sounded a little...degrarded (i guess the word would be), but nothing THAT noticable. It also takes longer to convert one song then it does to rip it off a CD.
Click to expand...

You mean degraded?
 
if you take a lossy format, and convert to a different lossy format, you will take more data out (different frequencies) you will ALWAYS end up with a lower grade finished product... NEVER re-encode something

Go from the source (CD etc.)
 
I've ripped a few 256kb mp3s to AAC and they sounds the same as the original mp3 file. So there no loss for me so far
 
Re: Re: Re: Time

Originally posted by paulwhannel
:rolleyes: it's the internet. if a typo is enough for you to bitch, go teach a HS typing class or something.
Click to expand...

If "(i guess the word would be)" was not there I would not have said a thing, but because it is I must talk smack. So settle down.
 
Originally posted by mac15
I've ripped a few 256kb mp3s to AAC and they sounds the same as the original mp3 file. So there no loss for me so far
Click to expand...

Many 192 MP3s to 128 AAC with no audible loss here also.
 
Not a noticeable enough difference

Originally posted by MorganX
Many 192 MP3s to 128 AAC with no audible loss here also.
Click to expand...

After using iTunes 4 to convert several 160 kbps MP3s to 128 kbps AAC's (noticing a neglible difference, if any), I let iTunes convert my entire 5 GB collection of MP3's to AAC's. I love this feature. It took about 9 hours (unsupervised), but it freed up almost 1.3 GB. That means I can put hundreds of new songs on my old 5 GB iPod. Works for me! (Way better than sitting in front of my computer for a couple of days swapping discs in and out and in and out...!)
 
look, they're not saying there is no loss of quality, they say it's small enough that they don't care. it's that simple. if it's not good enough for you then don't do it. it's a free world (mostly)
 
By converting MP3 to AAC you are lowering your expectations for sonic quality. Just convert everything from CD. Take the time. Come on, guys. It's good for us to keep our ears tuned.

I would naturally expect Mac users to have high expectations for every aspect of their tech experience.

Dan
 
Originally posted by alset
Come on, guys. It's good for us to keep our ears tuned.
Click to expand...

It's also a good thing for us to remember what's important in life. I spent this week sitting in front of my computer and feeding it more than 500 CD's. (I sit in front of my computer all day anyway; I'm a writer. So it wasn't a big deal for me.) I had encoded my library at 192 kbps, and I re-encoded it at 128 kbps in AAC format. Though a 128 kbps AAC sounds better by a country mile than a 128 kbps MP3, I can't tell the difference between a 128 kbps AAC and a 192 kbps MP3. Except for the fact that the AAC is 30% smaller, of course.

I did this because I believed what I was told. I believed that high-bit-rate MP3's converted to medium-bit-rate AAC's would sound bad. But after hearing all these people say that, I perversely decided to try it for myself anyway. Know what? I cannot tell the difference between a 192 kbps MP3 converted to AAC and an AAC ripped straight from the CD. Not on my SoundSticks, not on my iPod, not on my stereo. I simply can't tell which is which.

So all things considered, if I had it to do over again, I would just do a "select all" and let it convert everything. Converting is faster than ripping on a dual 1 GHz G4 (about 19x as opposed to about 14x), so I'm sure it would have torn through my collection of more than 5,600 songs in a reasonable amount of time, and I wouldn't have had to get my CD's down from the top shelves of the various closests in the house.

All my new music from now on, of course, will be encoded in AAC straight from the CD. And if I run into anything I just hate, I can always dig the CD out and re-encode it directly to AAC. But so far-- and I've been doing a LOT of listening these past few days-- I've run into nothing to complain about.
 
well to throw in my 2 cents here. I don't think that converting an mp3 to a lower bitrate mp3, or aac will necessarily yield noticably more degraded files then encoding it to that freq to begin with. After getting tired of people encoding crappy mp3's, i decided to only download 256 and 320 from the net. I convert those to wav and then use lame to encode to alt standard preset vbr mp3''s The files are usually a lot smaller and they sound identical, at least to my ear....and 4 other people's who have done a double blind test. Point is...it's in the converter, and the starting bitrate...i wouldn't bother unless the source was 256 or above, maybe 192, but i doubt it. Now, on my own double blind test today, I tested my lame vbr vs lame 192 vs aac 192 vs aac 128. My findings are 192 aac sounds brighter then lame vbr, but is slightly larger, and not compatable with my windows equipment. aac 128 sounds just about on par to me as lame 192, noticably smaller, again not compatable. both lame 192 and aac 128 have noticable artifacts, whereas aac 192 and lame vbr do not.

My $.02
 
I don't get it.

Why does everyone want their mp3s converted to AAC anyway?

If you say you don't care about sound quality... who gives a ****?

Same to jeff. If there's more important stuff in life, why screw around with mp3s? Just leave em.

I have 30mp3s. I'm leaving them all. Who cares.

Very few of you even have sufficient equipment to notice the difference anyway. This is all just a rush to do what's cool.

And that's all a lot of effort just to crap an extra 100 songs on your iPod or whatever.
 
Originally posted by springscansing
I don't get it.

Why does everyone want their mp3s converted to AAC anyway?

If you say you don't care about sound quality... who gives a ****?

Same to jeff. If there's more important stuff in life, why screw around with mp3s? Just leave em.

I have 30mp3s. I'm leaving them all. Who cares.

Very few of you even have sufficient equipment to notice the difference anyway. This is all just a rush to do what's cool.

And that's all a lot of effort just to crap an extra 100 songs on your iPod or whatever.
Click to expand...

definately also worth considering that if aac doesn't take off well, like wma didin't, you are stuck with aac if you decide to get another player that doesn't support it. You also can't trade easily, or use them on your windows machines easily. I would love to do aac but i won't. And for what its worth, take the pepsi challenge with wma at 128 vs aac at 128, you won't see a lick of diff. size or sound, Like it or not, and wma was out a lot earlier. DRM is a main reason aac is being pushed so hard. most of the world is on mp3, and it will take a while to change that, so prepare to be alone in your aac quest until it happens. Also, 3rd party utilities, like mass taggers and such are going to take a bit to get up to speed on aac.

now bear in mind i write this on a tibook and use this as my primary machine, so i am not an apple basher.
 
Originally posted by sparkleytone
Advanced: Convert selection to AAC
Click to expand...

I'm sorry but my iTunes only have 'Convert Selection to MP3'. I'm thinking of converting all my MP3 to AAC format too.

As I have different bitrate of MP3s and the reason for converting is to free up some space, is there a size difference between a 128bit MP3 and a 128bit AAC?

Thanks!
 
no, 128kbps is 128 kbps, the advantage is it sounds about as good as 192kbps mp3's. Meaning you can encode to a lower quality while keeping the better sound. The short answer is no, you won't save any space by converting 128 mp3 to 128 aac, and, your sound quality will go down converting. Now if you rerip all the cd's you will get a better sound at 128 aac
 
Originally posted by springscansing
Why does everyone want their mp3s converted to AAC anyway?
Click to expand...

Cause my 35 GB Music folder became a 26 GB Music folder.

And that's all a lot of effort just to crap an extra 100 songs on your iPod or whatever.
Click to expand...

I'm guesstimating that my approx. 650 song iPod became a 1,000 song iPod. And yeah, to me it's worth it. To be able to carry a third more music around with me for absolutely no money? You betcha I'll take the time to feed CD's into my computer for a good part of three days.

But, as I said, if I had it to do over again, I'd probably just have taken the easy route.

Also: Kaizer, go to your preferences and change your encoder from MP3 to AAC. The "Convert to MP3" command will become "Convert to AAC." And a 128 kbps MP3 converted to AAC will be no smaller, and possibly slightly larger. It only makes sense to either convert or re-rip if you have thousands upon thousands of 192 kbps MP3's on your hard drive, adding up to tens of gigs. If your collection is any smaller than that, you won't save enough disk space to make it worth your trouble.

Finally, remember: converting an MP3 of any bit rate to an AAC will never result in a file that sounds better. It will just result in a file that sounds the same. When you re-rip, you get AAC's that sound better than your MP3's did, even though they are the same size or smaller.
 
Thank for those tha replied. Guess I won't be converting all those MP3s then. My highest bitrate is 160kbps.

Comes to think of it...

I'm not fussy about sound quality as I can accept 128bit MP3. What if I convert all of them to a lower ACC bitrate equalvalent to 128bit mp3? What would be the correct AAC bitrate then?

Again, thanks for replying.
 
Originally posted by kaizer
What would be the correct AAC bitrate then?
Click to expand...

I have done a couple of informal tests at 96 kbps, and I found AAC's ripped from CD at that bitrate to be acceptable, but not perfect. To my ears, AAC's at 128 kbps are perfect. (And I have no particular desire to educate my ears further, thank you. I'm happy being able to enjoy my music without having to get fussy about the technicalities of its reproduction. It was a sad, sad day when I realized that a 128 kbps MP3 was annoying to listen to, and I'd just as soon not go through that experience again.)

XM Satellite Radio uses AAC encoding to approximate FM radio quality, and they use bit rates as low as 25 kbps. So try it. Set your encoder to 96K, or 64K, or even 32K, and see how the various encodings sound. If you're happy with one of them, then use it. You'll gain disk space on your computer and room for more songs on your iPod.

But be aware: if any of your friends or well-wishers are audio snobs, they WILL mock you for listening to such unacceptably compressed music. Of course, they probably already mock you for listening to 128 kbps MP3's through the cheap earbuds that came with your iPod anyway. If anybody suggests you buy a set of headphones carved out of teak by Guatemalan virgins and that cost more than you make in a month, you'll know that you can safely ignore that friend's opinions on the subject of audio reproduction.
 
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