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Holy Cow, My iTunes Library Shrunk!

wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
I worked out that, if I converted my entire library to 32-kbps HE-AAC (which sounds GREAT, mind you), from Apple Lossless... the space I'd save is just mind-blowing. My current music library size is 102 GB. I did the math, and worked out that, given my library's stats (14:07:59:41 total time, ~691 kbps average bitrate) that would shrink to ~3.43 GB after conversion... small enough to fit on a DVD. Can't say I can do that with my current music size. :eek:
 

marioman38

macrumors 6502a
Aug 8, 2006
886
69
Elk Grove, CA
32-kbps????????????
:confused:

:eek:

I wouldn't go anywhere below V2 (160-200kbps), my library is a mix of MP3 320, -v0 and -v2. Anything below has an audible loss in quality.
 
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Jaiden

macrumors member
Apr 6, 2008
70
0
I worked out that, if I converted my entire library to 32-kbps HE-AAC (which sounds GREAT, mind you), from Apple Lossless... the space I'd save is just mind-blowing. My current music library size is 102 GB. I did the math, and worked out that, given my library's stats (14:07:59:41 total time, ~691 kbps average bitrate) that would shrink to ~3.43 GB after conversion... small enough to fit on a DVD. Can't say I can do that with my current music size. :eek:

32kbps: There lies the problem. That's just way to small to possibly sound any good.

On the other hand, if your songs really are encoded at 700kb/s (I assume that includes videos, though, which are of course much much higher than music)...thats way too high to make any noticeable difference.

I keep my songs at 128-256kps and it's all goin good (much smaller library though...1/16th in fact)
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
32kbps: There lies the problem. That's just way to small to possibly sound any good.

On the other hand, if your songs really are encoded at 700kb/s (I assume that includes videos, though, which are of course much much higher than music)...thats way too high to make any noticeable difference.

I keep my songs at 128-256kps and it's all goin good (much smaller library though...1/16th in fact)
Nope. You'd be wrong about including videos. That average bitrate calculation EXCLUDES movies and other non-music content. Also, my bit rates are all over the place. Lowest bit rate: 34 kbps (2-way tie). Highest bit rate: 1180 kbps.
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
i'm sure he ment 320??
Nope. You're wrong. You're forgetting that iTunes limits HE-AAC encoding to 80 kbps... then again, that gives the same quality as a 320 kbps "normal" AAC file, which is, in turn, better than 320 kbps MP3, so that limitation isn't a real concern.
 
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Sdashiki

macrumors 68040
Aug 11, 2005
3,522
8
Behind the lens
Nope. You're wrong. You're forgetting that iTunes limits HE-AAC encoding to 80 kbps... then again, that gives the same quality as a 320 kbps "normal" AAC file, which is, in turn, better than 320 kbps MP3, so that limitation isn't a real concern.

No experience but how can something which is barely 1/10th the file size of the original (and thus missing 90% of the data) sound as good as something thats, say, 1/5th or 1/1 the size?

Compressing to save space is one thing, but you cant go backwards and make it sound original/better/higher bitrate later.
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
No experience but how can something which is barely 1/10th the file size of the original (and thus missing 90% of the data) sound as good as something thats, say, 1/5th or 1/1 the size?

Compressing to save space is one thing, but you cant go backwards and make it sound original/better/higher bitrate later.
Totally understand. You have to listen to an HE-AAC encoded file before you'll realize what I did, though. Also, I realized that I can save even more space by de-sampling to 32 KHz, since the native sampling rate of my source content is 32 KHz anyway... sure, I'll have to convert everything again, to get the highest quality. I don't mind doing that though. Finally, I realized that 32 kbps is a bit TOO low... after doing some more test encodes, 48 kbps HE-AAC seems to be the best balance between quality and file size.
 
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Sdashiki

macrumors 68040
Aug 11, 2005
3,522
8
Behind the lens
I dont know if my ideal music collection is one in which quality is usurped by size.

When the future comes, as tomorrow always does, you may not be happy with your decision. Backing up lossless is a good idea, but then whats the point of having a full library AND a compressed on?

Maybe you should just go for the future and buy bigger storage.
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
I already have a 1TB drive. I'm not doing this to free HD space. I'm doing it so that I can take my music collection with me, on my 64GB iPod touch. So far, the space savings has been drastic. I've already converted one section of my library to 64 kbps HE-AAC. Sounds just as good as ALAC to me... and I'm getting almost 14:1 space savings (27.88 GB -> 2.07 GB).

I'm convinced that HE-AAC is the future format of the iTunes Store, someday.

EDIT: I'm backing up the lossless files now, as I type this.
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
Just finished converting the remaining 10,634 songs that still needed to be converted. That took awhile - I ran it overnight.

Now, my library is 9.46 GB rather than 102 GB... a savings ratio of about 43:4 (or 10.75:1). :D
 
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Capt Underpants

macrumors 68030
Jul 23, 2003
2,861
3
Austin, Texas
Why did you encode in lossless to begin with? Seems like you would've found some kind of middle ground (say 256 kbps MP3's w/ the LAME encoder) instead of going from CD quality to ****.

What's your usual signal chain from the computer to your ear?

32, 48, and 64 kbps tracks sound terrible. But then again, a lot of people listen to music through iPod earbuds and can't appreciate flat, uncolored sound when they hear it.
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
Wow!

128kbps is bad enough...

That must sound absolutely crap!

Why did you encode in lossless to begin with? Seems like you would've found some kind of middle ground (say 256 kbps MP3's w/ the LAME encoder) instead of going from CD quality to ****.

What's your usual signal chain from the computer to your ear?

32, 48, and 64 kbps tracks sound terrible. But then again, a lot of people listen to music through iPod earbuds and can't appreciate flat, uncolored sound when they hear it.
Both of you are ignoring the fact that I used HE-AAC (High Efficiency AAC), NOT regular AAC. HE-AAC at 64 kbps sounds just as good as regular AAC at 256 kbps, which, for all intents and purposes, is indistinguishable from Apple Lossless encoding. I'm completely serious - try this some time:

Import one track from a CD, in 256 kbps AAC, 64 kbps AAC (which sounds awful), and 64 kbps HE-AAC. You'll probably find, like I did, that you can't tell the HE-AAC file apart from the regular AAC file, except for the dramatically reduced file size. HE-AAC (v1, mind you, not v2) support is new in iTunes 9.
 
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harperjones99

macrumors 6502
Nov 3, 2009
497
0
I'd bet most people wouldn't "hear" the difference in a blind test. They see the numbers and it's all mental.
 
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Capt Underpants

macrumors 68030
Jul 23, 2003
2,861
3
Austin, Texas
Both of you are ignoring the fact that I used HE-AAC (High Efficiency AAC), NOT regular AAC. HE-AAC at 64 kbps sounds just as good as regular AAC at 256 kbps, which, for all intents and purposes, is indistinguishable from Apple Lossless encoding. I'm completely serious - try this some time:

Import one track from a CD, in 256 kbps AAC, 64 kbps AAC (which sounds awful), and 64 kbps HE-AAC. You'll probably find, like I did, that you can't tell the HE-AAC file apart from the regular AAC file, except for the dramatically reduced file size. HE-AAC (v1, mind you, not v2) support is new in iTunes 9.

I'll try it sometime w/ some Adam A7's and a treated room. Really the only way you can test something like this. What's your signal chain again? I just want to know what speakers you're judging the "quality" of this on.

I don't know much about compression algorythms and "perceived quality", but I do know something about sound. Losing that much data makes me very wary.

I have a lot of compressed music, but I'm working on going back to AIFF files. With hard drive space as cheap as it is, there's no real incentive for compression. When I listen to music, I listen to music.
 
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wrldwzrd89

macrumors G5
Original poster
Jun 6, 2003
12,107
75
Solon, OH
I'll try it sometime w/ some Adam A7's and a treated room. Really the only way you can test something like this. What's your signal chain again? I just want to know what speakers you're judging the "quality" of this on.

I don't know much about compression algorythms and "perceived quality", but I do know something about sound. Losing that much data makes me very wary.

I have a lot of compressed music, but I'm working on going back to AIFF files. With hard drive space as cheap as it is, there's no real incentive for compression. When I listen to music, I listen to music.
The signal chain? From iTunes, to the computer's built-in internal speakers (this is a C2D Rev. C iMac we're talking about), to my ears.
What software are you using to encode in this format? Yes I can do a search, but I am curious as to what the OP is using.

Thanks
I'm using iTunes 9.0.2 to encode in HE-AAC. It shares an extension with regular AAC (which makes sense, given the way iTunes treats AAC files with different profiles). I've attached a screen shot of the encoding settings I'm using, to help everyone else that's interested.
 
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