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Maybe you should have used a compressed lossless format.  1GB per album would seem to be about three times larger than necessary.

Maybe you should have used a compressed lossless format.  1GB per album would seem to be about three times larger than necessary.

I probably have a fair few more than 600 albums but I have a ton of external storage so size isn't really an issue (or so I have been told). Even keeping to Apple Lossless however I would still consume an uncomfortable amount of hard drive space on my Mac which is why I'd like to find the best compromise with the best AAC bit rate. I'm playing from iTunes on my Macbook so while I am a great believer in lossless formats it wouldn't be being played to its full potential here anyway.

Good morning.  Here's what I would do as it seems you are in the Apple Eco-system:  Spend the $24.99/year to subscribe to iTunes Match and upload all of your lossless files to the Cloud.  The Cloud will accept Apple Lossless, AIFF, or WAV; as well as lossy MP3 or AAC.  I'd go with lossless as your 1st option for uploads.  In most cases, iTunes will match your music with AAC iTunes Plus files.  In the cases there aren't matches, iTunes will transcode the lossless files to AAC iTunes Plus files.  AAC iTunes Plus is Constrained Variable Bit Rate 256kbps files.

If you have other Apple devices you can use iTunes Match to download or stream your Cloud music as you see fit.  They will all be available across your devices in the iTunes Plus format.  This is also a great time-saver once you get through the initial uploads.  Make sure your metadata is how you want it before you start because it's easier to do it right the 1st time rather than fix it later.

For what it's worth, bitrates above 160kbps are generally overkill with a good AAC encoder like iTunes or FhG AAC.

Hope this helps.  Best regards, LedHed8

P.S.- Added Bonus -- You won't have to use local storage on any devices if you don't want, and the iTunes Cloud will do the lossy encoding for you.

I don't really want to fork out more than I already have to our mighty overlords in Cupertino, especially as I can easily set my Mac to encode my lossless library into 256kbs or higher AAC overnight and while I think 600-700 lossless albums might choke my Mac, it would probably cope with having the same library 2-3 times smaller.

I'm mostly confused about the VBR part, as I vaguely remember a while back people were saying there was no point having 320kbs as a variable bit rate because 320kbs was as high as it could go anyway, I don't think AAC could even do 320kbs VBR at one point in time?

From what I can understand, when iTunes does VBR it basically sets the chosen bit rate as the minimum and from there it goes higher depending on the track (except for silence when it goes lower) is that right? So a track encoded at 256kbs could go up to 275kbs or something like that? Thus VBR is superior to CBR in that regard, which is why iTunes Plus uses VBR for its encoding.

Would that mean then that in theory 320kbs VBR AAC is superior to 320kbs CBR AAC because the VBR would encoded the track at 320kbs as a minimum and only go higher or is there nowhere for it to go after 320kbs and thus it's just wasted space? A couple of tracks I encoded with both were obviously slightly bigger encoded using 320kbs VBR but I couldn't tell any noticeable difference (nor would I expect to).

I literally just want to encode at what would be the highest quality AAC bit rate and while I can find enough arguments about whether 256kbs is good enough for most people and that you can or cannot tell the difference when tested, and a few arguments from some about 320kbs being detectably better than 256kbs, I can't find anything at all about 320kbs being theoretically or audibly better using VBR or not. In fact a lot of the information is out of date now as some sites say AAC won't even DO VBR at 320kbs.

I'd really appreciate it if someone could run me through this, even if it's to appease my own curiosity.

Would that mean then that in theory 320kbs VBR AAC is superior to 320kbs CBR AAC because the VBR would encoded the track at 320kbs as a minimum and only go higher or is there nowhere for it to go after 320kbs and thus it's just wasted space?

You've already long passed the point of wasted space.

I'd really appreciate it if someone could run me through this, even if it's to appease my own curiosity.

https://hydrogenaud.io/index.php/topic,16295.0.html

600 albums lossless would be around 200GB.

That matches what I see in my collection.

The sound quality difference between 256kbps and 320kbps AAC is vanishingly small almost all of the time. You are far more likely to imagine a difference than hear a real one. You are also quite likely to get annoyed at having to maintain two collections in sync every time you rip a new disc, or correct a problem you find in the metadata when playing the tracks. Of course if you want to load everything on to a lower capacity portable player, you'll have to do this, but it's nice if it can be avoided.

Cheers,
David.

If 128k tests are stress inducing then in real life listening it should be perfect or very close. IMO no reason for 256k which may fail on other critical sample. If people cannot handle the risk of some minor difference then maybe forget lossy compression. For small collections you can have as much or even more music compared to 128..192 of 10yrs ago.

 A decade ago or so , ripping into mp3 128~192:  600 cd's = 35GB.   No compatibility issue or transcoding. Sound quality is near transparent. With mirror backup = 70GB.

Today with lossless + multi collections:  200GB lossless + 100GB (additional HQ lossy libs for pc / phone).  With backup = 600GB. 

If using many formats, it seems a new problem is emerging worse than 1 lossy or lossless. It may also involve a lot of work esp if you can't transcode directly into a device and have to maintain multi collections.

Thanks for this topic and all answers, I'm just before digitization of my CD's archive, really a lot of CD's, I would like to ask one last follow up question related to this thread.

Lossless compression would be still overkill for me - SD cards space capacity is limited, I bought 256 GB, with FLAC I would have to drastically limit my digital collection and omit many of great CD's so I'm going to go lossy way and AAC/M4A as this is popular currently and used in iTunes as well so I would stick to one format, but...

Encoding of so much CD's is a lot of work, If I'm going to do it, I would like to keep as insane quality as possible, even if there is completely no reason for that now (maybe in next ~10 years there will be better audio equipment available with more affordable prices). Thus I would like to encode my CD's to lossy format, but with insane quality to save as much quality as possible.

As far as I understand - qaac.exe wrapper for iTunes encoder gives probably the best quality. But highest possible bitrate for it is 320 kbps.
With --cbr 0 --quality 2 --no-optimize it is producing nice files, fast and without any Hz cutoff.
I have tested fdkaac.exe, but no matter what encoding options I will set - I see cutoff at 20 kHz.

Finally I give a try with neroAacEnc.exe and I see that with VBR it can go up to 400 kbps also no cutoff, but in other hand Nero AAC Encoder is not updated for last 6 years and I'm afraid that maybe there is risk for some bugs there.

The question is:
Despite that it is probably stupid anyway - if I would choose between
- qaac --cbr 0 --quality 2 --no-optimize (320 kbps)
- neroAacEnc with VBR quality 1.0 (400 kbps)
I should go with option 1 or option 2 (despite that Nero is not updated anymore) to save as much quality as possible?

PS: Please don't be mad - I really want to save as much data as possible and I would go lossless, but SD cards capacity is still too low for my CD's collection

@greynol - thanks for answer, fully understand You and I know that in fact I could even go with lower bitrate and I still wouldn't be able to point on which file is encoded with what bitrate in blind test

Generally my point is just to preserve as much audio data as it is possible when going lossy way and it's just because I can't go lossless way

Encoding file with 320 kbps gives bigger size that in 256 kbps - of course this even says less about real encoding quality, but is this mean that some more of audio data is preserved? I don't want to irritate anybody, just asking - to be sure that I will encode my collection once and I won't have to do that ever again You know - a lot of work Maybe even few months...

Do yourself a favor, kadet, and use lossless codec to encode the CDs you extract. Keep the lossless files on your computer or external hard drive and convert from those to portable use as needed. The CD extraction process is the most time consuming part of your project and it makes no sense to have to redo it.

You can easily re-encode the collection with new codec or bitrate without quality loss in case your requirements change. If you want to include more music per SD card just re-encode with a lower bitrate. AAC has great quality even at 128 kbps.

Higher bitrate usually means that frequency cutoff is higher and psychoacoustic threshold for audibility is lowered so that more of the less important parts are included. But this isn't a guarantee that higher bitrate file has better quality if they are from different encoders or they are encoded with some custom encoding parameters. Different encoders have different psychoacoustic models, they may not utilize all the features of the format and they can have bugs.

For example Nero encoder has tremendous trouble with the beginnings and endings of tracks and it gives audible artifacts even at ridiculously high bitrates with some gapless tracks.

Higher bitrate usually means that frequency cutoff is higher and psychoacoustic threshold for audibility is lowered so that more of the less important parts are included. But this isn't a guarantee that higher bitrate file has better quality if they are from different encoders or they are encoded with some custom encoding parameters.

You mean the threshold of audibility is raised, not lowered. Regardless, if the threshold of audibility is not reached with a lower bitrate then the quality of the encode is not any worse than if it was made with a higher bitrate.

I just don't see the point of not going lossless with CD rips. You would anyway need an offsite backup, and a larger hard drive does not cost that much (for most music collections).

And lossless rips can be repaired ... of course that only matters if they were erroneous. I uploaded a badass sample: https://hydrogenaud.io/index.php/topic,113978.new.html

LTP, if you *really* want to stick with AAC, choose 256 kbps VBR. Higher bitrates would be waste of space because it's not so likely for you to hear any difference between 256 kbps and 320 kbps. Just do an ABX test
I can recommend you WavPack. If you set encoder to hybrid mode, you can get 2 files: one high-quality lossy file (it can go down to around 200-300 kbps) and second, correction file. These 2 files combined in decoder produce lossless music restoration, however lossy WavPack file's quality is enough (at least for me  )