Should i start using AAC? Can you notice a better quality? Options

[Bahamut2]

I have read everywhere that it is better than MP3, but will i be able to notice the difference?
I encode all my files to VBR -V0 and i don't know anything about AAC, what would be the equivalent encoding settings for AAC?

Can you people really notice that theyre is a reall difference in quality? I want to test it by myself (encoding always it max quality off course) but first i want to ask here.

[JunkieXL]

I used to use LAME v1 for all of the files I would put on my iPod. When they released the iTunes Plus preset a while back, I started to test that out and found that I couldn't tell the two apart and that I was getting better battery life on my iPod when using AAC files.

LAME v1 is in the 200 to 250 kbs VBR range IIRC and iTunes Plus is in the 256 kbs VBR. (That reminds me that they need to update the bitrate listing in iTunes when looking at a files info. It says 256 on all files no matter how simple or complex the track is.)

I haven't tested at lower settings as I have enough space on my iPod for the larger file sizes.
CK

This post has been edited by JunkieXL: Jan 10 2012, 20:24

[Defsac]

LAME v1 is in the 200 to 250 kbs VBR range IIRC and iTunes Plus is in the 256 kbs VBR. (That reminds me that they need to update the bitrate listing in iTunes when looking at a files info. It says 256 on all files no matter how simple or complex the track is.)

iTunes 'VBR' used to be constrained VBR at least in the older versions, even though the QuickTime engine is capable of encoding true VBR. That is probably why all your files are reading 256kbps. I have not used the iTunes frontend in a while so I'm not sure if this is still the case. XLD for OS X uses the Quicktime encoder and can be set to produce true VBR, I'm not sure whether there are programs for Windows capable of the same thing using Quicktime.

I have heard people speculate Apple chose CVBR for iTunes because they were worried about users being confused about songs resulting in different bit rates even though the quality settings were the same, but I don't know how accurate that is. iTunes (on OS X at least) also used to have issues with calculating bit rates on true VBR AAC files but this may have been fixed since.

Edit: Just did a quick test with the latest iTunes using 256kbps VBR, the resulting file reads as 256kbps in iTunes and 269kbps in OS X Finder. XLD using constrained VBR produced a file that reads as 269kbps in both Finder and iTunes. I suspect iTunes is deliberately displaying the bit rate as 256kbps when the files are produced through iTunes conversion.

Edit 2: Someone posted this in another thread for Windows.

This post has been edited by Defsac: Jan 23 2012, 10:15

[Nessuno]

Anyway, if one uses XLD or any other QuickTime frontend, to produce AAC from his own lossless material, it's better to target for quality (range 0 ~ 127) instead of bitrate. Target quality of 110 roughly corresponds to 255Kbps VBR, but the real average bitrate of a track, which is the value both Finder and iTunes show, actually depends on source complexity.

This post has been edited by Nessuno: Jan 23 2012, 18:42

[slks]

Anyway, if one uses XLD or any other QuickTime frontend, to produce AAC from his own lossless material, it's better to target for quality (range 0 ~ 127) instead of bitrate. Target quality of 110 roughly corresponds to 255Kbps VBR, but the real average bitrate of a track, which is the value both Finder and iTunes show, actually depends on source complexity.

While I agree that theoretically, a properly designed "true VBR" mode is better than ABR - the recent AAC listening tests here showed that for Apple's encoder, the "Constrained VBR" mode (which I suppose is like ABR) actually scored better.

I'm no expert at statistics or reading these listening test graphs, but it seemed that the Constrained VBR setting did score marginally better. (And both modes scored better than Nero AAC). My guess is that Apple has not tuned their true VBR mode as much as they have the constrained VBR.

[C.R.Helmrich]

the recent AAC listening tests here showed that for Apple's encoder, the "Constrained VBR" mode (which I suppose is like ABR) actually scored better.

Sorry, that is not what the test showed. The average scores alone don't tell the whole story. Please read the text above (and below) the result plots on the test page.

I'm no expert at statistics or reading these listening test graphs, but it seemed that the Constrained VBR setting did score marginally better. (And both modes scored better than Nero AAC). My guess is that Apple has not tuned their true VBR mode as much as they have the constrained VBR.

Again, I disagree. True VBR averaged 6-7 kbps lower in bit-rate than constrained VBR while not performing significantly worse in terms of quality. So it seems very well tuned. (That said, on the items tested, TVBR is tied to the Fraunhofer encoder whereas CVBR is significantly better than it).

Chris