Once again, the classic MP3 vs. AAC

neoelectronaut

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Dec 3, 2003
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I'm sitting here with my iTunes library, and it's around half AAC and half MP3. Which is really the better encoder? What's the best quality for the filesize?

I'm considering doing a complete re-rip of my collection. Hopefully iTunes likes to "overwrite" music and not put duplicates of it all over my HD. I'm already at 1/2 my HD capacity as it is.

http://www.xciv.org/~meta/audio-shootout/
 

Blue Velvet

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Jul 4, 2004
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I've gone for MP3 320kbs VBR etc. with iTunes encoder only because I do make discs for the car occasionally and for other people... this can sound pretty good.

I tried the LAME encoder but couldn't get it to work properly.

AAC is OK if you're going to just use it at home and your iPod.

One day, I'd like to go Apple Lossless but I think I'd need a new hard-drive.
 

Blue Velvet

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Jul 4, 2004
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neoelectronaut said:
Is VBR a good idea? Doesn't the quality like fluctuate throughout the song or something?

Wouldn't 320 take up a LOT of HD space?
I thought VBR was OK but I don't know that much about it and yes, it does take up a lot of space... approx 35gb for 293 albums but that's what a 160gb HD is for. I don't do video so the music folder is the biggest folder on the drive. Apart from that, any freelance graphic work is archived onto DVD anyway... I don't like tons of completed work sitting on my HD.
 

neoelectronaut

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Blue Velvet said:
I thought VBR was OK but I don't know that much about it and yes, it does take up a lot of space... approx 35gb for 293 albums but that's what a 160gb HD is for. I don't do video so the music folder is the biggest folder on the drive. Apart from that, any freelance graphic work is archived onto DVD anyway... I don't like tons of completed work sitting on my HD.
Well I have a 160GB HD also (149GB, grr.) but it's down to about 74GB free, so I'm getting a little paranoid on space. I think I may just stick to 192. It's not like I can really tell the difference anyway.
 

Jetson

macrumors 6502a
Oct 5, 2003
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I rip AAC at 192 kbps bitrate. The sound quality of AAC at a decent rate (over 128 kbps) is better than MP3 IMO. I've seen frequency analysis which shows that the AAC encoder does a better job at more closely duplicating the original signal waveform than MP3, which drops off significantly in amplitude above 15khz.

I'd like to use Apple lossless. However I can't detect any difference in sound quality with my ears, so I don't see the benefit of using lossless at the cost of consuming approximately 5 times more disk space.

If you are planning to use your music in a dance hall or stadium where it will be played at high volume then you should consider lossless. Reproduction on high quality equipment at high volumes may reveal the "airyness" of the compressed source.
 

Mord

macrumors G4
Aug 24, 2003
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i encode at 160kbps aac and switch to lossless if it something really good
 

daveL

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Jun 18, 2003
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AAC is better than MP3 at any bit rate (that's why they're now pushing MP3+). I use AAC @ 192 kbps. Given that AAC is part of the open mpeg4 spec, I really think that's the way to go.
 

wrldwzrd89

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Jun 6, 2003
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HE-AAC beats 'em all

HE-AAC (the official name for aacPlus) does for AAC what MP3PRO (not MP3+) did for MP3. It is capable of delivering the same quality at half the bitrate. That means that a 128 kbps HE-AAC file is theoretically the same quality as a 320 kbps MP3 file. Apple hasn't deployed it yet though.
 

Diatribe

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Jan 8, 2004
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Back in the motherland
I rip everything at 224kbps AAC. This is where I stop hearing a difference on my headphones, which are pretty good ones. The first equipment I notice a difference again is on my dad's but he has $10,000 speakers.

So 224 AAC for my PB and Lossless on my external HD. So the next step I will take will be from 224 AAC to Lossless. I figure HDs will be big enough for that in 3-4 years and until then I don't think I will be able to afford $10,000 speakers :D

I have about 6000 songs at about 7MB per song at 224 AAC.
 

wrldwzrd89

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Jun 6, 2003
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Everything I've ripped is in Apple Lossless. I refuse to use anything else until HE-AAC becomes available to iTunes users.
 

Mord

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Aug 24, 2003
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aac dose suck for base, i was listening to hey hey my my by neil young and it sounded like crap coming from my hi-fi from my ibook (just noticed it as i usually dont listen to stuff that has lots of bass
 

daveL

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Jun 18, 2003
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MP3PRO

wrldwzrd89 said:
HE-AAC (the official name for aacPlus) does for AAC what MP3PRO (not MP3+) did for MP3. It is capable of delivering the same quality at half the bitrate. That means that a 128 kbps HE-AAC file is theoretically the same quality as a 320 kbps MP3 file. Apple hasn't deployed it yet though.
MP3PRO, right. I read a Creative ad for their MP3+ product, and it stuck in my head, sorry.

I read somewhere that HE-AAC actually removes high frequencies during encoding and then synthesizes them during decoding, thereby actually modifying the original content. I understand that any lossy compression modifies the original content, but this seems to me to go one step beyond. I haven't heard HE-AAC, yet, so I can't judge the sonic impact. Not that my hearing is that good, these days.
 

daveL

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Jun 18, 2003
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Hector said:
aac dose suck for base, i was listening to hey hey my my by neil young and it sounded like crap coming from my hi-fi from my ibook (just noticed it as i usually dont listen to stuff that has lots of bass
You could always use the equalizer to boost the bass frequencies, when needed. I think you can actually set the equalizer preference on a per-song basis.
 

asif786

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Jun 17, 2004
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it really depends on personal needs - i have brothers and we sometimes swap music, so MP3 works quite well in terms of compatibility..

At the moment I only have 185 songs in my itunes library because I'm replacing all my music with music bought from the music store..odd I know but hey..!

A good thing to do is rip all your CD's to Apple lossless, put them on DVD to archive. Then choose format and convert them. If you decide later on that you screwed up, you have it all ready to re-rip :)

/asif
 

asif786

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Jun 17, 2004
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daveL said:
You could always use the equalizer to boost the bass frequencies, when needed. I think you can actually set the equalizer preference on a per-song basis.
I actually keep my EQ on Bass Booster all the time. I dont know if it's because I mainly listen on headphones, but I like my music to have some depth when I'm listening to it..

/asif
 

wrldwzrd89

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Jun 6, 2003
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daveL said:
MP3PRO, right. I read a Creative ad for their MP3+ product, and it stuck in my head, sorry.

I read somewhere that HE-AAC actually removes high frequencies during encoding and then synthesizes them during decoding, thereby actually modifying the original content. I understand that any lossy compression modifies the original content, but this seems to me to go one step beyond. I haven't heard HE-AAC, yet, so I can't judge the sonic impact. Not that my hearing is that good, these days.
That is somewhat correct. It doesn't so much remove the high frequencies as record enough information to simulate them with SBR technology. Here's a link to a site comparing HE-AAC (referred to as aacPlus, which isn't the official name) to MP3 and original uncompressed WAV. All test files are in WAV format, so you don't have to worry about not being able to play the HE-AAC files.
 

madmaxmedia

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Dec 17, 2003
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Is VBR a good idea? Doesn't the quality like fluctuate throughout the song or something?
It shouldn't. Certain passages of music have less 'information' than others, VBR takes advantage of this to save some space during encoding while still preserving good overall sound quality.

Regarding AAC vs. MP3, it largely depends on the MP3 encoder. The MP3 encoder built into iTunes isn't very good, so AAC is definitely better than that.

Comparisons to the LAME encoder seem to be more subjective. Many say that LAME is up there with all the "next-gen" encoders, including the AAC encoder in iTunes (not that this won't be improved further as well.) I don't listen to my iTunes music on my stereo anyways, so I've never done any critical testing myself. But I use LAME because MP3 is still a more universal format (for now.) But if you're an iPod user for life then this doesn't matter.

The developer of QuickSilver makes a great LAME plug-in for iTunes-

http://blacktree.com/apps/index.php

The install package includes the encoder, so the whole process should be simple and painless. Insert a CD, and after iTunes picks up the artist and track info, fire up the LAME script. The music is automatically added to your iTunes collection as well. Best results are typically attained using the alt preset standard setting, which is a finely tuned 192 kbps VBR setting.

The biggest disadvantage of using LAME is that it's pretty slow (much slower than the iTunes MP3 encoder.) Not good at all if you are trying to convert your entire CD collection!
 

dogmo1001

macrumors newbie
Dec 3, 2004
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wrldwzrd89 said:
HE-AAC (the official name for aacPlus) does for AAC what MP3PRO (not MP3+) did for MP3. It is capable of delivering the same quality at half the bitrate. That means that a 128 kbps HE-AAC file is theoretically the same quality as a 320 kbps MP3 file. Apple hasn't deployed it yet though.

At least according to the hype. ;)


If HE-AAC works similarly to Mp3Pro, it uses a trick to reduce the sample rate (not bit rate) of the source file to 22.05 kHz (from 44.1) and then uses another trick to effectively return the sample rate to the standard 44.1 kHz. It involves 'comparing' the wave form above and below the zero line, storing any differences that are found, so that something close to the original wave can be 'reconstructed' on playback, which is accomlished by 'mirroring' the top and bottom of the wave forms and 're-inserting' the differences that have been stored. Standard Mp3s are, for playback purposes, very close to a wave format and there is little actual 'decoding' going on during playback. Which is why it's relatively easy to create a compatible mp3 player -- but NOT to create an encoder (which must use 'perceptual encoding' to remove 'unnecessary information' from the original file).

If you play an Mp3Pro file in a non-Mp3Pro player, it will play, but quality will be reduced (significantly if you've got the monitor and the ears to tell) and it will show in the display as a "22 kHz" file. A Pro capable player, on the other hand, will 'decode' the file and 'reconstruct' a semblance of the original wave form.

In my exprience, an Mp3Pro file is roughly 40-45% smaller in filesize than a standard Mp3 of more or less equal quality.

When size isn't a consideration -- or dissemination is (as in a band putting out their music as mp3s) and quality is important, I like the LAME encoder doing the highest level of VBR. But the latest Thomson/Fraunhofer 'official' Mp3 encoders are very fast and are, arguably, more or less in the same quality range.
 

neoelectronaut

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Well, hate to dredge up an old topic, but just wanted to note that I'm almost done re-ripping to 192 MP3. I know in about 6 months or so I'll probably end up going back to AAC, but well, I guess that's just how things go...

Problem is, any plans of me picking up a 20GB iPod have just been thwarted as I have crossed the 20GB threshold. Guess I'll have to plan to get a 40GB one now. *sigh*
 

wrldwzrd89

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Jun 6, 2003
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neoelectronaut said:
Well, hate to dredge up an old topic, but just wanted to note that I'm almost done re-ripping to 192 MP3. I know in about 6 months or so I'll probably end up going back to AAC, but well, I guess that's just how things go...

Problem is, any plans of me picking up a 20GB iPod have just been thwarted as I have crossed the 20GB threshold. Guess I'll have to plan to get a 40GB one now. *sigh*
I have a 40 GB iPod - all of my music won't fit on it. Soon, I'll reach the point where even the 60 GB iPod Photo won't be enough. Oh, and while we're on the topic...I've been busy re-ripping everything to Apple Lossless.
 

Nermal

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Dec 7, 2002
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neoelectronaut said:
Well I have a 160GB HD also (149GB, grr.) but it's down to about 74GB free
What are you complaining about? :eek: My 160 GB drive (144 GB usable after installing TechTool eDrive) is down to 33 GB free. And I'm not really worried about it filling up, because I've copied practically all of my music, apps and movies onto it.

Unlike some people, I don't have a HUGE music collection. I have 19 GB of music, most of it's MP3, with some AAC, plus some .mov music videos, some MPEG videos, and quite a few stream-ripped RealPlayer videos.
 

neoelectronaut

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Nermal said:
What are you complaining about? :eek: My 160 GB drive (144 GB usable after installing TechTool eDrive) is down to 33 GB free. And I'm not really worried about it filling up, because I've copied practically all of my music, apps and movies onto it.

Unlike some people, I don't have a HUGE music collection. I have 19 GB of music, most of it's MP3, with some AAC, plus some .mov music videos, some MPEG videos, and quite a few stream-ripped RealPlayer videos.
Well I started out with my 160GB HD also (In reality only 149GB) and I'm now down to around 79GB. Though, I keep telling myself that I need to go through and delete some stuff: Duplicate PSDs, old anime and videos I don't watch anymore, etc. Not to mention the games I hardly play anymore.

And in the end I can just grab a handful of DVD-Rs and get to the burning...

But uh...yeah, as far as iTunes, I'm so freaking paranoid. Will MP3 take up TOO much space? With AAC save space but sound worse? I am wasting my time re-ripping to MP3 and am gonna have to take another week in the future off just to get back to AAC if I decide to?

It's nervewracking.
 

Abstract

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Dec 27, 2002
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Oh geez, buddy, take a pill and chill.

If you swap songs with people, and are concerned with maintaining the ability to do so with non-iTunes users, then just stick with 192kbps Mp3. But otherwise, use AAC and leave it be. If you were so concerned about quality, you wouldn't even use compressed formats. So if you've been okay with the quality of your music at 192 kbps/160 kbps or less, keep it and save yourself the work.

At this very moment, I'm converting all my CDs to 160 kbps AAC, not 192 kbps or higher because I can't be bothered and can't hear much of a difference unless I'm listening to a lossless file immediately after hearing the same song at 160 kbps (mp3 or AAC). I'm only doing all this work because my iPod will have better battery life and skip protection (I'm a jogger) if my file sizes are smaller. Some of my files used to be at 320kbps, that's all.