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Should I convert all my audio to 256 AAC?
DaGrandMastah
post May 3 2012, 14:51
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Hi all, I'm currently researching what the best route is to go with when converting over my CD library. I realize that everyone loves Lossless (which I'll use for archiving the CD's) but I'm looking for "the best" lossy encoding.

I was originally planning to encode all my CD's into 320 CBR but it seems that almost everything I read states that this is a waste of space as their is nary a difference (except to the most trained ears) between 320 CBR and VBR v-0. Ultiamtely, I don't mind the difference in space when on my computer hard drive but it does become more of an issue when uploading to my iphone for portable listening so then I switched course and started thinking I would go with VBR v-0 (I posted a similar question to this in the mp3 forum) but now I'm reading that I may even be better off going with AAC 256?

This may make the most sense for me being that I'm a Mac user (imac, iphone, ipad) and I'm going to playing all my music out of my itunes library.

Is there any reason I would regret the decision to go AAC over mp3?

Also, for those with experience with this, could you direct me to the best possible setting to use in XLD for encoding CD's/FLAC files to aac?
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pdq
post May 3 2012, 14:57
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As long as you still have the lossless files there is no wrong answer.

If you do some serious listening tests (i.e. double-blind ABX testing) you will probably find that even 256 kbps is very much overkill, especially for portable listening. I don't use AAC, but many people recommend 128 kbps for portable use.
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Porcus
post May 3 2012, 15:01
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QUOTE (DaGrandMastah @ May 3 2012, 15:51) *
Is there any reason I would regret the decision to go AAC over mp3?


You might encounter devices (like, a car stereo?) without AAC support. If you keep the lossless files, it is merely the nuissance there and then though.


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DaGrandMastah
post May 3 2012, 15:08
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QUOTE (pdq @ May 3 2012, 15:57) *
As long as you still have the lossless files there is no wrong answer.

If you do some serious listening tests (i.e. double-blind ABX testing) you will probably find that even 256 kbps is very much overkill, especially for portable listening. I don't use AAC, but many people recommend 128 kbps for portable use.


Yeah, the thing is that I have a LOT of music to convert....and it's not just converting but properly tagging with artwork and putting it in the exact format I like within the itunes file/folder structure so I'd like to avoid having to redo anything by researching the topic beforehand.

One thing I can say, and I am not an audiophile in the slightest, is that I can tell the difference in 128 kb mp3 and 256 kb mp3 on my iphone.
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DaGrandMastah
post May 3 2012, 15:52
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Also, what are the best (recommended) settings for converting to AAC? Is it 256 AAC CBR?
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pdq
post May 3 2012, 17:25
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QUOTE (DaGrandMastah @ May 3 2012, 10:08) *
Yeah, the thing is that I have a LOT of music to convert....and it's not just converting but properly tagging with artwork and putting it in the exact format I like within the itunes file/folder structure so I'd like to avoid having to redo anything by researching the topic beforehand.

I would think that this is simply a matter of making sure that the lossless files are all properly tagged and everything, then use software that duplicates all of this exactly when you convert to lossy. If at some time you are not satisfied with the quality or file size, simply repeat with the new settings.

Edit: I don't use itunes, but I thought it had the ability to convert on-the-fly from lossless to lossy as it downloads to your DAP? You could then use different settings at different times with no additional effort.

This post has been edited by pdq: May 3 2012, 17:27
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felix26591
post May 3 2012, 19:14
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QUOTE (DaGrandMastah @ May 3 2012, 16:52) *
Also, what are the best (recommended) settings for converting to AAC? Is it 256 AAC CBR?


I woudn't really recommend 256kb AAC it's still too high you would still not notice the diference between 192kb or 168kb. Do a blind ABX test on the diferent qualities of AAC to know which one suits you best. As you are all apple AAC is the best way to go. You could get better quality of Vorbis but then you have compatability problems. Go AAC anywhere from 128KB-192KB which every suits you best.
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DaGrandMastah
post May 3 2012, 19:45
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QUOTE (felix26591 @ May 3 2012, 20:14) *
QUOTE (DaGrandMastah @ May 3 2012, 16:52) *
Also, what are the best (recommended) settings for converting to AAC? Is it 256 AAC CBR?


I woudn't really recommend 256kb AAC it's still too high you would still not notice the diference between 192kb or 168kb. Do a blind ABX test on the diferent qualities of AAC to know which one suits you best. As you are all apple AAC is the best way to go. You could get better quality of Vorbis but then you have compatability problems. Go AAC anywhere from 128KB-192KB which every suits you best.


Thanks for the suggestion. I'm still leaning more towards 256 as I'd like to eliminate the chances that, like has happened before, my hearing tastes change/improve and I regret not going higher. Perhaps I won't notice it now, but maybe I'll notice it later?

So if I do end up going that route, would Tru-VBR settings be the way to go?

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mixminus1
post May 3 2012, 19:55
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If you're planning on ripping to lossless, pdq's suggestion is the way to go: rip to ALAC using XLD, make the ALACs your iTunes library, and then encode on-the-fly when you sync your devices.

You can try the different bitrates - 128, 192, and 256 - and see if you can even tell the difference. You'll always have the ability to change your mind on a whim and use a different bit rate by just resyncing.


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Kohlrabi
post May 3 2012, 21:01
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QUOTE (DaGrandMastah @ May 3 2012, 16:52) *
Also, what are the best (recommended) settings for converting to AAC? Is it 256 AAC CBR?

Please don't use CBR encoding, unless you have known bad decoders or are running a streaming site. It only wastes spaces, defeating the whole purpose of lossy encoding.

QUOTE (DaGrandMastah @ May 3 2012, 20:45) *
So if I do end up going that route, would Tru-VBR settings be the way to go?

Yes. It's advisable to do ABX tests to determine your sweet spot concerning the target bitrate/quality setting. For safety you might want to slightly increase the quality setting above that threshold when encoding your final files.

Lossless encoding will trade off HD space vs. not having to spend time on re-ripping if you find out that your lossy encodings are not appropriate.

This post has been edited by Kohlrabi: May 3 2012, 21:03


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JJZolx
post May 3 2012, 21:27
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QUOTE (DaGrandMastah @ May 3 2012, 08:08) *
Yeah, the thing is that I have a LOT of music to convert....and it's not just converting but properly tagging with artwork and putting it in the exact format I like within the itunes file/folder structure so I'd like to avoid having to redo anything by researching the topic beforehand.


How many CDs do you have?

I'm just wondering if the space saving is worth all of the hand wringing.
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DaGrandMastah
post May 4 2012, 00:18
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QUOTE (JJZolx @ May 3 2012, 22:27) *
QUOTE (DaGrandMastah @ May 3 2012, 08:08) *
Yeah, the thing is that I have a LOT of music to convert....and it's not just converting but properly tagging with artwork and putting it in the exact format I like within the itunes file/folder structure so I'd like to avoid having to redo anything by researching the topic beforehand.


How many CDs do you have?

I'm just wondering if the space saving is worth all of the hand wringing.


I'm honestly not sure. Definitely over 100 but prolly less than 200.

I thought about possibly doing ALAC but I still think I'd prefer to go with AAC as the primary source. That being said, I will likely rip to ALAC over FLAC just in case.

I'll have to look at the settings in XLD to determine what's best. Anyone have experience using that program on Mac?
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RobertoDomenico
post May 4 2012, 01:09
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Just listen to your lossless (ALAC) files in iTunes. When transferring to a portable have iTunes transcode it on the fly to AAC to either 128, 192 or 256 CBR. For me 128 is plenty for portables. By far the easiest simplest way to manage your music, one library and all your metatdata stays the same everywhere.

This post has been edited by RobertoDomenico: May 4 2012, 01:15
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JJZolx
post May 4 2012, 01:38
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QUOTE (DaGrandMastah @ May 3 2012, 17:18) *
QUOTE
How many CDs do you have?

I'm just wondering if the space saving is worth all of the hand wringing.


I'm honestly not sure. Definitely over 100 but prolly less than 200.


200 CDs encoded losslessly in ALAC (at 0.33 GB per CD) is less than 70 GB. At today's ~$100 for a 1 TB drive, that should cost you only about $7 in hard drive space. Unless you're really pressed for hard drive space, the space savings of using a lossy format (and its bitrate) shouldn't be much of a consideration at all. It might be different if you had 10,000 CDs and didn't want to pay for or maintain all the drive space required.


QUOTE
I thought about possibly doing ALAC but I still think I'd prefer to go with AAC as the primary source. That being said, I will likely rip to ALAC over FLAC just in case.


ALAC over FLAC makes sense when your environment is mostly Apple and iTunes. In any case, if you choose a lossless format, you can readily convert everything to a different one at a later date, with no penalty and with minimal effort. That's not the case with lossy formats.

Where space and lossy encoding settings are an important consideration is in use on portables, like iPods. A lower bitrate means both better battery life and more songs that can be loaded load into limited storage space.

I would rip the CDs to ALAC, then keep a mirror library encoded in AAC or Mp3 if you want to load files onto an iPod. The disk space required for a lossy mirror library of 200 CDs should be less than 25 GB of space. And once again, if the main library is in a lossless format, the decision of which bitrate/quality level to use becomes much less unimportant, since you can always re-encode the library to another bitrate at a later date.

This post has been edited by JJZolx: May 4 2012, 01:44
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DaGrandMastah
post May 4 2012, 02:03
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QUOTE (JJZolx @ May 4 2012, 01:38) *
QUOTE (DaGrandMastah @ May 3 2012, 17:18) *
QUOTE
How many CDs do you have?

I'm just wondering if the space saving is worth all of the hand wringing.


I'm honestly not sure. Definitely over 100 but prolly less than 200.


200 CDs encoded losslessly in ALAC (at 0.33 GB per CD) is less than 70 GB. At today's ~$100 for a 1 TB drive, that should cost you only about $7 in hard drive space. Unless you're really pressed for hard drive space, the space savings of using a lossy format (and its bitrate) shouldn't be much of a consideration at all. It might be different if you had 10,000 CDs and didn't want to pay for or maintain all the drive space required.


QUOTE
I thought about possibly doing ALAC but I still think I'd prefer to go with AAC as the primary source. That being said, I will likely rip to ALAC over FLAC just in case.


ALAC over FLAC makes sense when your environment is mostly Apple and iTunes. In any case, if you choose a lossless format, you can readily convert everything to a different one at a later date, with no penalty and with minimal effort. That's not the case with lossy formats.

Where space and lossy encoding settings are an important consideration is in use on portables, like iPods. A lower bitrate means both better battery life and more songs that can be loaded load into limited storage space.

I would rip the CDs to ALAC, then keep a mirror library encoded in AAC or Mp3 if you want to load files onto an iPod. The disk space required for a lossy mirror library of 200 CDs should be less than 25 GB of space. And once again, if the main library is in a lossless format, the decision of which bitrate/quality level to use becomes much less unimportant, since you can always re-encode the library to another bitrate at a later date.


Thanks for the help. So I got the lossy part down now...definitely doing ALAC.

Would these be good settings for my AAC encoding? Should I go higher or lower on the target quality?



This post has been edited by DaGrandMastah: May 4 2012, 02:03
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RobertoDomenico
post May 4 2012, 03:33
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If iTunes is your music player of choice just transcode to AAC with iTunes. It will make your life 1000 times easier having to only manage one lossless library. iTunes will transcode to AAC on the fly.

If you must use XLD for AAC then i wouldn't use True VBR since i have found them to skip during playback on some ipod models. My personal opinion i would use 128 VBR Constrained.

This post has been edited by RobertoDomenico: May 4 2012, 03:38
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DaGrandMastah
post May 4 2012, 04:15
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I heard that was only in the older apple models but doesn't occur anymore.

Wow. I'm learning a lot from this thread. Thanks a lot guys...you've been a great help here.

So I'm almost decided but I had a question. I just spent some time testing the differences in size between mp3 vbr v0 and aac true vbr with target quality at 110 and i'm noticing that certain albums, the aac files come out slightly larger....and in other folders, the aac files are the smaller ones.

Is that because AAC true vbr allows for the file to exceed a specific rate while the mp3 vbr constrains the rate at 256?
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RobertoDomenico
post May 4 2012, 05:24
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Using LAme Mp3 they will not playback gapless over home sharing on iPod Touch and iPhones. Just keep that in mind (One day we can hope Apple will fix this)

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Engelsstaub
post May 4 2012, 06:14
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Most often I convert my lossless sources with XLD to AIFF and drag them into iTunes. From thence I let iTunes encode these files to the "iTunes Plus" settings and delete the AIFFs. (Many here will tell you that iTunes Plus bit rate is overkill, but I do it more for the sake of uniformity. I also subscribe to iTunes Match FWIW.)

When I do let XLD do the encoding it is 256 Kbps VBR constrained with "Encoder quality" set at max. I don't think it makes much difference either way at that bit rate.

If you plan on subscribing to iTunes Match in the future these may be the "optimal" settings. ALAC/encoding to the iPod on the fly, as some posters have encouraged, is also a good alternative. Me personally: as long as my files are archived lossless (as they are,) I would keep AAC files on the computer. It may matter if at a later date you want to migrate to, say, a MBA with limited SSD space.

Just my thoughts.


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DaGrandMastah
post May 4 2012, 12:28
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QUOTE (Engelsstaub @ May 4 2012, 07:14) *
Most often I convert my lossless sources with XLD to AIFF and drag them into iTunes. From thence I let iTunes encode these files to the "iTunes Plus" settings and delete the AIFFs. (Many here will tell you that iTunes Plus bit rate is overkill, but I do it more for the sake of uniformity. I also subscribe to iTunes Match FWIW.)

When I do let XLD do the encoding it is 256 Kbps VBR constrained with "Encoder quality" set at max. I don't think it makes much difference either way at that bit rate.

If you plan on subscribing to iTunes Match in the future these may be the "optimal" settings. ALAC/encoding to the iPod on the fly, as some posters have encouraged, is also a good alternative. Me personally: as long as my files are archived lossless (as they are,) I would keep AAC files on the computer. It may matter if at a later date you want to migrate to, say, a MBA with limited SSD space.

Just my thoughts.


Thanks for the info. I don't notice any difference between true vbr or constrained at that bitrate either so I'm just gonna test out a couple more and go with whatever produces the smaller file size (which appears to be True VBR).

I plan on doing the same as you. I am going to have my computer HD filled with all the AAC files and have a lossless backup of all my audio for archiving purposes.

Do you know what iTunes uses to encode their audio? Just curious if they're going with vbr or cbr?
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Engelsstaub
post May 4 2012, 12:43
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QUOTE (DaGrandMastah @ May 4 2012, 06:28) *
...

Do you know what iTunes uses to encode their audio? Just curious if they're going with vbr or cbr?


VBR.


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pdq
post May 4 2012, 13:05
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QUOTE (DaGrandMastah @ May 3 2012, 23:15) *
Is that because AAC true vbr allows for the file to exceed a specific rate while the mp3 vbr constrains the rate at 256?

mp3 vbr is not constrained to 256 unless you specifically tell the encoder to do so. Otherwise it is free to use as many 320 frames as it feels necessary.

There could be many reasons why, even if both encoders are targeting the same quality, one encoder could achieve that quality more easily than the other due to differences in the codec format.

Also, determining what is or is not a certain quality level is not an exact science. One encoder may use different criteria than another and so make different choices as to what it keeps and what it does not keep.
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DaGrandMastah
post May 4 2012, 16:07
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You guys have been a tremendous help. Ok so after weighing all my options I think I've decided on going with

VBR contstrained at 256 kbps with quality set to max to avoid any possible skipping on the true vbr.

or

True VBR with quality set to max at 127

I was noticing that, while the constrained VBR is slightly higher in size then the true vbr, it is still significantly lower than 320 kpbs mp3 cbr.

My understanding is that, while it's not imperative that i match itunes settings, the rate I indicated above matches it closely and I've always found the quality of the music on itunes to be great.

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Ouroboros
post May 4 2012, 16:44
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Constrained VBR is still wasting bits. I'm sure that XLD's uses Quicktime for AAC encoding, and if Quicktime's true VBR skipped there'd be loads of posts about it.

Just go for true VBR, and let the encoding algorithm decide on the appropriate bit rate for each frame it encodes. Apple's encoders have been developed for a long time, and like LAME for MP3 there are very few bugs left, and they perform very well in the comparative listening tests. If True VBR had issues they would show up in the listening tests.
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DaGrandMastah
post May 4 2012, 16:56
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QUOTE (Ouroboros @ May 4 2012, 16:44) *
Constrained VBR is still wasting bits. I'm sure that XLD's uses Quicktime for AAC encoding, and if Quicktime's true VBR skipped there'd be loads of posts about it.

Just go for true VBR, and let the encoding algorithm decide on the appropriate bit rate for each frame it encodes. Apple's encoders have been developed for a long time, and like LAME for MP3 there are very few bugs left, and they perform very well in the comparative listening tests. If True VBR had issues they would show up in the listening tests.


So then the only question is....what target quality should I set? Should I use 110 which is estimated at 256...or 127..which estimates it at about 320.

I noticed that the true vbr quality 110 was showing some files coming in as low as 180 kbps per second...but i'm assuming that's due to the complexity fo the song not requiring all those extra bits.
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