Do Apple Lossless files really sound the same as AIFF?

[souptin]

Hey to all you fringe scientists and big brains debating here:

 

Since I've confessed to having trouble sometimes telling high bitrate files from lossless I can't claim to have much of a say in this particular discussion, but the memory player issue has been bothering me and I wonder if anyone has investigated:

 

Do the various 'memory capable' players simply load the file to be played into memory, and then decode and send to dac from there, or do they first decode (if for example it is a flac or alac lossless file) into uncompressed pcm while loading into memory.

 

I'm guessing that the second option would be better, assuming that the issue being addressed is the processing, but I don't ever recall the question being answered. In fact I suspect the former in the case of Amarra (based on it's own memory usage display).

 

Anyone know? Anyone care?

[sone]

Do the various 'memory capable' players simply load the file to be played into memory, and then decode and send to dac from there, or do they first decode (if for example it is a flac or alac lossless file) into uncompressed pcm while loading into memory.

 

The second. Here's ALAC's source code:

 

 

163 Decode()164 - the decoded samples are interleaved into the output buffer in the order they arrive in

165 the bitstream

166 */

167 int32_t ALACDecoder::Decode( BitBuffer * bits, uint8_t * sampleBuffer, uint32_t numSamples, uint32_t numChannels, uint32_t * outNumSamples )

[sone]

LOL! Read what I wrote instead of trying to ferment discord.

 

Fermenting is what gasbags do.

[souptin]

The second. Here's ALAC's source code:

 

What program?

[sone]

Apple builds all their audio stuff on top of their CoreAudio API, so that means iTunes, QuickTime, afconvert, hitting play in Finder, and so forth.

[souptin]

Ok thanks anyway. I was more interested in the specialist playback software. Has anyone else investigated?

[sone]

Also the second, e.g. Best Sound Quality | Audirvana.

[Paul R]

(grin) You have a sense of humor, so you probably didn't come from the Gasbag Forum (which is a real place with the name slightly obfuscated, not a person).

 

Seriously, you are arguing the wrong argument. Nobody argues that digital data isn't perfect or identical - of if they do they are seriously living in a different world than the majority of us. But different audio playback chains can take the exact same digital data and produce a different analog output. And that's the kicker, in Audio, everything comes down to the analog output, sooner or later.

 

General wisdom says that the longer you can keep the data in the digital domain, the less the impact of the analog conversion. That's only general though, as you can easily hear differences between most DACs when inserted into the exact same playback chain. Why? Partly of course, because of the analog conversion. But also partly because of the differences in filter choices, chips, and implementation.

 

As I said, you are arguing from the wrong point. Consider that most people neither care nor differentiate about anything other than the final sound, and from that point of view, it is perfectly valid to say two digital files or digital formats sound different. If you dig deeper, it becomes clear they are really saying that the same digital file sounds different if you change the playback chain. Both statements are perfectly reasonable, and hardly controversial, if you understand what they people are saying and what they actually mean. And if you dig even deeper, it gets more and more interesting to some of us.

 

Now, there is a certain internet forum out there - which I fondly refer to as the "gasbag forums" where tunnel vision is the rule, not the exception. You will, in general, find the exact opposite is true here.

 

People on CA spend a lot of time and effort trying to understand each other, as well as the concepts and revealed data from audio experience and experimentation. Sure, we are a bunch of opinionated souls, but that is because pretty much everyone here is passionate, as indeed, you also seem to be.

 

-Paul

 

 

 

Fermenting is what gasbags do.

[Jud]

Also the second, e.g. Best Sound Quality | Audirvana.

 

Yes, as can be seen from this quote at the linked page:

 

Complete file loading, decoding, processing (if needed), and conversion to DAC native format are performed offline, before playback.

 

Which is immediately followed by this sentence:

 

Thus minimizing the computer load in sync with the audio signal, that is the most detrimental to sound quality.

 

I pointed out, and spdif-usb and others have as well, that what we are thinking of with regard to any audible difference between uncompressed and losslessly compressed formats would be the result of additional computer load associated with processing the compressed format. You previously expressed skepticism on that score (if I am reading your responses correctly). Damien's quote, and the theory behind other memory players, suggest disagreement with your position (again, if I read it accurately) that there would be negligible audio effect from any additional load resulting from on-the-fly decompression.

 

There is an additional issue with regard to memory players: Wouldn't loading the decompressed file into memory before playing eliminate any audible effect? Once everything is loaded into that RAM buffer, certainly we must be beyond the place where any minor changes affect audibility, right?

 

So sone, I've got a home experiment to suggest to you. For best results, you will need a PC running Win 7 with a good fast CPU and plenty of RAM. 8 GB is good, more is better. The experiment is this: Set up the XXHighEnd player on your computer. It's a memory player. I can give you suggested settings for the various items that one can tweak with XXHE. Then I'd like you to keep all the settings the same except one, the Split File Size (SFS) setting. The only thing this affects is how many MB of the music file are loaded into memory at a time. Try it with a setting of 1 or 2, then something like 340 or 430. (I believe you have to stop and start the music for changes to this setting to take effect, but I don't think XXHE itself needs to be restarted in between.) Or have someone else do it for you, if you'd like a blind test. See what the p value is for whether you can hear a difference, when the only change is the size of the file chunks being loaded into RAM prior to playback.

[Superdad]

Jud & Paul & Souptin, etc:

The point you are getting at, while not entirely new, makes (almost) perfect sense, and aligns well with my personal (and public) experience in demonstrating significant sonic difference in playback of ALAC versus AIFF.

That was back in 2008 with a 1GB G4 Mac mini and no memory play s/w. With my 8GB 2.4GHz 2010 mini and Aurdirvana, the differences are EXTREMELY subtle in my sensitive system. So this again supports what I think should now just be generally accepted: That audible differences between lossless and never compressed files are due to computer load (and whatever attendant affect that has on internal radiation, power supply load, etc.), and not due to how the bits are stored on the HD.

 

 

To me, this still leaves a couple of issues unanswered:

1) With memory playback s/w feeding bits from RAM after decompression (this certainly proved by watching Activity Monitor processor/drive activity when first loading a file, then seeing it drop to almost nothing--and the drive light going out--once a few seconds into song play), why should there be ANY sonic differences at that point?

 

BTW Jud, I doubt that Sone will go to the trouble of doing the experiment you propose--but perhaps someone else will. I already enjoy all the combined benefits of A+'s Exclusive, Direct, Integer, and Memory Play modes, so I don't need convincing. That said, I do not see a way in A+ to turn off Memory Play entirely. 256MB is the lowest one can set the slider.

 

 

2) SandyK claims that the quality of the rip (into whatever format) is affected by the optical drive, its power supply, and the rip software/settings used. There are an awful lot of devotees to EAC, dBPoweramp, XLD, etc., and unless they are all using those programs to get good rips of scratched discs, or because they like the file tagging capabilities, or just out of paranoia, then perhaps there is something real there. Me, I've been happily using iTunes (with "Error Correction" on) for years to rip all my non-scratched CDs to AIFF. Ripped one with XLD last month and compared it to the same disc ripped with iTunes and heard zero difference. So I am still a bit baffled and skeptical in this regard.

 

BTW, SandyK: You might want to become familiar with Mac minis from the past 3 years. All Mac minis since the introduction of i5 and i7 models do not even have an optical drive (solid faceplate), and one can buy any thin or thick external made, Firewire or USB.

And I am afraid that Steve Nugent's love for the 2009 mini is misplaced. Last year, when I was choosing which mini to replace my G4 with, I bought both a 2010 Core 2 Duo and a 2011 i5 mini. I also had the 2009 Intel mini that had been my desktop work machine. One of the 3 was to become my dedicated music server, one would be my new desktop work machine, and the 3rd place finisher would go to my wife/kids in the living room.

All 3 machines were fitted with 8GB RAM, a totally clean and slimmed OS X install, Pure Music and A+. The whole thing was very methodical and controlled (and I even did OS comparisons). The clear looser of the 3 machines?: The 2009 Mac mini. It even lost out when powered by the giant 10amp external regulated linear supply that I had been using with the G4 (which I have yet to be able to hook to the slim minis as I have not had the time to do the internal cable/PS surgery to use an outboard).

 

Well, the sunny Sunday is beckoning. Cheers to all.

--ALEX

[sandyk]

BTW, SandyK: You might want to become familiar with Mac minis from the past 3 years. All Mac minis since the introduction of i5 and i7 models do not even have an optical drive (solid faceplate), and one can buy any thin or thick external made, Firewire or USB.

ALEX

I will take your word for it, as I have no interest in the Mac Mini. In that case, I expect that most will be using an external Optical device via USB, not Firewire.

My own experience of thousands of hours playing around in the USB area, tells me that it is capable of vast improvement, both in the PSU and cable areas. This means that both Macs and PCs have similar needs in that area to obtain the highest

quality Audio performance.

Kind Regards

Alex

[sone]

This is a discussion about there are differences between lossless formats played through the same channel, not different channels. AAC sounds a lot better out of my Burr Brown than AIFF does out of my iPhone, but so what? The relevant question asked by the OP is whether there's a difference playing ALAC and WAV on the same computer to the same DAC over the same interconnect.

 

The fact that all software being discussed concerts whatever lossless file you're playing in memory then sends the exact same bytes to the DAC means that there is no audio difference between lossless formats.

 

The processor cost of the codec could be an issue if it were CPU or memory intensive, but it's neither—just the opposite. It takes a second to decode about 5 minutes of ALAC audio. Try it yourself:

 

time afconvert --file WAVE --data LEI16@44100 --verbose track_alac.m4a track_alac.wav

 

That's a factor of 300x. So even if the lossless codec were doing something stupid like running constantly with no buffering (it doesn't—the source code link is above), that means at worst a 0.3% CPU load for the codec. But the load for kernel_task is a constant 5–10%, so if it were really the case that the audio of ALAC is degraded by codec processing, computer audio would be a dead letter anyway just from having to run the kernel. But of course it's not and the codec CPU load is irrelevant to audio.

 

I have listened to various lossless formats on my own system to make sure that the codec software itself isn't borked, and I've found all lossless formats to be intisinguishable, as expected with no bugs.

[sandyk]

The fact that all software being discussed concerts whatever lossless file you're playing in memory then sends the exact same bytes to the DAC means that there is no audio difference between lossless formats.

 

Perhaps, but that doesn't mean that it sounds exactly the same as the original, as many members who actually use their ears with better than average equipment, instead of just quoting incomplete/ outdated theory, have already posted in this thread, and even far more have posted in numerous other C.A. threads. There is still a lot to learn about digital audio, as there is also about the full capabilities of human hearing.

 

SandyK

 

 

 

 

 

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"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com

[sone]

I've been happily using iTunes (with "Error Correction" on) for years to rip all my non-scratched CDs to AIFF. Ripped one with XLD last month and compared it to the same disc ripped with iTunes and heard zero difference. So I am still a bit baffled and skeptical in this regard.

 

I used to use EAC exclusively. I happily switched platforms when Apple adopted BSD, but was leery of iTunes ripping after I heard it produce popping from clean CDs. I used EAC's sample comparison mode and saw that iTunes was indeed producing bad rips. So I switched to cdparanoia on Macports, and except for it's lack of an EAC-like sample offset correction, it's perfect. The problem with iTunes was inadequate error correction—EAC's and cdparanoia's strong suite. This information may be obsolete at this point and iTunes may have improved its ripping quality, but I remain skeptical given my experience.

 

Assuming good error correction, CD rips will be exact copies of the CD, and other issues like drive power supply are completely irrelevant.

[sone]

Woops, correction: cdrdao for whole disk rips and DAO copies, and cdparanoia for single tracks. Both are available from Macports:

 

sudo port install cdrdao cdparanoia

 

Scripting helps speed the process, as well as adding meta data to AIFF/ALAC/ACC files. cdrdao hits a freedb server for track information, which it can use (quaintly now) for CD-TEXT.

[sandyk]

Assuming good error correction, CD rips will be exact copies of the CD, and other issues like drive power supply are completely irrelevant.

 

Assuming good error correction in the CD player/CDRom, then why do the Sony BluSpec comparison CDs that have the same check sums, sound different when played directly? Highly respected Recording and Mastering Engineer Barry Diament has also reported this in a post he made some time back, where he initially thought that both CDs sounded like they were from different masters.

SandyK

 

 

 

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"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com

[wgscott]

Also via fink.

 

I maintain a precompiled binary dist of fink debian packages, including these, if anyone is interested. Makes it fairly pain-free.

[wgscott]

why do the Sony BluSpec comparison CDs that have the same check sums, sound different when played directly?

 

One could take this as the operational definition of expectation bias.

[sone]

Also via fink.

 

According to my listening tests, the exact rips from cdrdao from the Macports distribution are sonically superior to exact rips from cdrdao from the fink package manager.

 

Seriously, Irving Reed just passed. He was a great guy who never saw a penny from RS codes, so if you're enjoying your CDs and perfect tips, raise a glass to Irving.

[sandyk]

One could take this as the operational definition of expectation bias.

I would expect that somebody of Barry's vast experience is more than capable of ensuring that when he reports things like this in a forum, that he has managed to overcome any expectation bias. I would also expect that the Sony Engineers who created the BluSpec format, as well as the CD format in conjunction with Philips, have a wee bit more experience in this area than most.

Regards

Alex

 

 

Signature

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"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com

[sandyk]

BTW, BluSpec CD is still going strong in Japan ,but is now superseded by BluSpec2

 

"Blu-spec CD2 is the next generation Compact Disc that employs the Phase Transition Mastering, the technology developed for mastering of Blu-ray discs, to further perfect the acclaimed characteristics of Blu-spec CD2. Fully compatible with standard CD players, Blu-spec CD2 completely alters the experience of music."

 

 

 

 

 

 

 

 

Signature

--------------------------------------------------------------------------------

"If you can't hear the difference between an original CD and a copy of your CD, you might as well give up your career as a tester. The difference between a reconstituted FLAC and full size WAV is much less than that, but it does exist."-Cookie Marenco. cookiemarenco.com

[wgscott]

According to my listening tests, the exact rips from cdrdao from the Macports distribution are sonically superior to exact rips from cdrdao from the fink package manager.

 

I knew you (or someone) would say that!

[Superdad]

Assuming good error correction in the CD player/CDRom, then why do the Sony BluSpec comparison CDs that have the same check sums, sound different when played directly? Highly respected Recording and Mastering Engineer Barry Diament has also reported this in a post he made some time back, where he initially thought that both CDs sounded like they were from different masters.

SandyK

 

Well BluSpec is simply a variation in the laser used to make the glass masters which are then used for the injection moulding to press CDs. It has been known for years that better defined pits and lands of a finished CD make the job of real-time playback easier (less on-the-fly error correction required), and that the quality of both the glass master and the pressing will affect the sonics of the final CD. But it is my understanding that a big part of the advantage of computer audio comes from "data-mode ripping" (I forget the technical term) which either eliminates or greatly lessens the effects of poorly pressed CDs, with the ripping process yielding an error-free file. Ever notice how some brand new CDs make your optical drive go nuts with tons of whirring and seeking, with the error corrected rip taking sometimes 5x longer? I think those are the poor CD pressings (either due to a lesser glass master or a poor pressing process). But once they are ripped, the files sound fine.

 

I Googled many ways and can not find any reference to the existence of "Sony BluSpec comparison CDs." I also suspect that if they sound better (assuming exact-same-audio-chain masterings/pressing exist of any title--a BIG assumption), it is only when played back real-time on a CD player, not when comparing proper rips of the same two discs.

 

Oh look, I just found the Barry Diament quote that supports EXACTLY what I just wrote (last paragraph being the key:

 

"Friends, the key is the mastering. If it uses the same mastering as the plain version of the CD, I find the Blu Spec/SHM version gets you closer to that mastering. If it uses a different mastering, the results are going to depend on how you feel about that mastering job.

 

The point is, Blu Spec or SHM don't make anything "better". They just give you a clearer view of the source used to make them.

 

If the masterings are the same, I'd want the Blu Spec or SHM (if I was going to listen via a transport or player). If they're different, I'd want the mastering I prefer, regardless of the manufacturing recipe.

 

I said "if I was going to listen via a transport or player" above because that is where I find the sonic differences will manifest themselves. Assuming both versions are from the same mastering, if you're going to extract the disc to hard drive and listen via a "music server" app (e.g. iTunes, etc.), the plain CD will give you exactly the same results as the Blu Spec or SHM."

--Barry Diament Blu Spec Recommendations ? | Steve Hoffman Music Forums POST#24

[jhwalker]

Well BluSpec is simply a variation in the laser used to make the glass masters which are then used for the injection moulding to press CDs. It has been known for years that better defined pits and lands of a finished CD make the job of real-time playback easier (less on-the-fly error correction required), and that the quality of both the glass master and the pressing will affect the sonics of the final CD. But it is my understanding that a big part of the advantage of computer audio comes from "data-mode ripping" (I forget the technical term) which either eliminates or greatly lessens the effects of poorly pressed CDs, with the ripping process yielding an error-free file. Ever notice how some brand new CDs make your optical drive go nuts with tons of whirring and seeking, with the error corrected rip taking sometimes 5x longer? I think those are the poor CD pressings (either due to a lesser glass master or a poor pressing process). But once they are ripped, the files sound fine.

 

I Googled many ways and can not find any reference to the existence of "Sony BluSpec comparison CDs." I also suspect that if they sound better (assuming exact-same-audio-chain masterings/pressing exist of any title--a BIG assumption), it is only when played back real-time on a CD player, not when comparing proper rips of the same two discs.

 

Oh look, I just found the Barry Diament quote that supports EXACTLY what I just wrote (last paragraph being the key:

 

"Friends, the key is the mastering. If it uses the same mastering as the plain version of the CD, I find the Blu Spec/SHM version gets you closer to that mastering. If it uses a different mastering, the results are going to depend on how you feel about that mastering job.

 

The point is, Blu Spec or SHM don't make anything "better". They just give you a clearer view of the source used to make them.

 

If the masterings are the same, I'd want the Blu Spec or SHM (if I was going to listen via a transport or player). If they're different, I'd want the mastering I prefer, regardless of the manufacturing recipe.

 

I said "if I was going to listen via a transport or player" above because that is where I find the sonic differences will manifest themselves. Assuming both versions are from the same mastering, if you're going to extract the disc to hard drive and listen via a "music server" app (e.g. iTunes, etc.), the plain CD will give you exactly the same results as the Blu Spec or SHM."

--Barry Diament Blu Spec Recommendations ? | Steve Hoffman Music Forums POST#24

 

Exactly.

[sandyk]

Superdad

BluSpec releases, are available from CD Japan.

Regards

Alex