Apple Lossless vs AAC

rjgrichmond wrote:

Thanks for the clarification. So I guess it's kind of like filling the additional space in the bigger box lossless file size with styrofoam.

Yes, that is a good analogy.

If you rip a track from CD with Apple Lossless, you get the full sonic detail that was on the CD.

If you then compress it to AAC and then expand it back to Apple Lossless, it will expand but will not recapture the detail that was lost. Kind of like the bird at the bottom.

Wow, we need some clarity and definitions here.

1. Apple Lossless Audio Codec ("ALAC") compresses the information on a CD (or other source), but without losing any information (lossless). The Free Losless Audio Codec ("FLAC") is a similar "coder-decoder" ("codec") method (or algorithm), but it's just not owned by Apple. When you play a file encoded using ALAC, you are playing back (decoding) the music with all the detail of whatever source you used to encode the file. What's great about lossless compression is that can sound just as good as a CD. What's bad about lossless compression is that the files are BIG: one pop song is going to be 30-40MB. A lossless file should be made ONLY from a CD, a live recording or other high-quality source.
2. MP3, AAC, etc. are "lossy" compressions. They throw out all the information that some engineers decided weren't "important" enough, or wouldn't make any difference when listening on earbuds, and for the most part, that's true. Most importantly, once a song has been encoded using lossy compression, there is NOTHING you can do to restore that lost information. What is great about lossy compression is that the files are MUCH smaller. What's bad is that when you play a file encoded with lossy compression on a good stereo, with a good Digital-Analog Converter ("DAC"), you will notice a huge difference, a lack of detail or "muddiness" in the sound, less dynamic range (the difference between loud and soft passages), loose bass and less crispness in the treble.
3. To answer the specific question, yes, you could turn an AAC or MP3 file into an ALAC or FLAC file, but there's no point. Once the "extra" information is lost, it's gone, and there ain't no getting it back from the lossy file. The only way to make that same song worth using 10x the storage space is to re-encode the file from the CD, otherwise, you're just putting make-up on a pig. It don't actually look good; it's just gussied up for no reason whatsoever.
4. Much of the cost of a good CD player is in the DAC, so if you want to play your music that you've stored on your computer in lossless format and really make it worth using 10 times the storage space, you need to have (a) good speakers - like better tires on a car, it's the best way to improve your sound system; (b) a good receiver/amplifier to power those speakers cleanly; and (c) a good outboard DAC. Yes, it's an extra gizmo, but even the best amp and speakers can't make a bad signal sound good. A stereo won't make a song you hate sound good to you, right? I personally recommend the Schitt Audio Bifrost (http://schiit.com/products/bifrost), but there are other good products out there (see http://lifehacker.com/five-best-digital-to-analog-converters-dacs-483393503).
5. I store the songs I love in ALAC because hard drive space is pretty reasonable nowadays, but I convert them to AAC when I sync them to the iPhone. Even if you have fancy $300 headphones from Mr. Andre Young, your iPhone doesn't have enough clean power to make it worth storing songs on your iPhone in ALAC. That's the reason they make headphone amplifiers. When I want to blast the sound in the house, I use an old 3rd-gen AppleTV to get the file from iTunes to the Bifrost, and then to the amp and speakers. Sounds wonderful. 🙂

I have not known many situations where things were absolutely prevented just because they were not a good idea. 🙂 I'm at a loss to think of a situation where you would want to go AAC to ALE but probably there is one.

I haven't tried AAC to ALE and I don't know the details of how the codecs work. One thing for certain though is you cannot recover lost information. Let's say the AIFF to AAC encoder says, "Let's toss out this quiet guitar playing a C note because there's a loud drum roll right here. Nobody is going to hear it and we can save a bit of data encoding to cut down file size." When you convert to ALE there's no way it is going to know there was originally a C being played quietly in that section.

Converting from AAC to Lossless does not drop anything, but that's not what Limnos said. He said that converting cannot recover anything that was discarded during the compression to AAC.

iTunes has the capability of converting any of the formats it can use to any of the other formats. That doesn't mean that doing so makes sense, just that Apple's programmers didn't see any point in locking out any conversion. Someone may have a good reason why they want all their tracks in Lossless format, even if they don't gain sound quality in having it so.

Regards.

I just used a sound generator to creat a pure 30s 1kHz signal. I saved it as 128k .m4a, a lossless format, and as AIFF.

AIFF 5.1 MB

lossless 0.92 MB

.m4a 0.36 MB

As I said before, I don't know the details of the codecs. Typically a lossless format file will be about 60% the size of an AIFF file and the 128k .m4a about 10%. My examples are much smaller so both probably reflect the minimal descriptive encoding required because of the purity of the sound. Still, the lossless file is 3x the .m4a version which I suppose has something to do with the coding structure since both are very simple in terms of waveform. You would have to check on on an audiophile web site to find an explanation.

The stereo guy wasted your time. There will be no benefit in doing making such a conversion, at least none that makes it worth the time and effort. Based on testing I've seen done on Apple's Lossless format in the past, any improvement you hear is most probably the "placebo effect" and not any real difference in the waveform, though I can't say with absolute certainty that there is no difference in the decoders in iTunes that might account for some small difference in playback.

Regards.

I'm still interested in understanding the technical distinction between an AAC file and a lossless file converted from that same AAC song.

There is none. The conversion to ALE, because it is lossless, gives you an ALE file that has exactly the same sonic content as the AAC that you started with. That is what "lossless" means.

The conversion from AAC to Apple Lossless does in fact not

improve anything.

There is a case for the conversion though. You can convert

an AAC to lossless and then use audio enhancement software

on it to "improve it" or just simply make it sound like you want

that simple playback adjustments cannot do. Then, if you

keep it in lossless, none of changes will get thrown out.

If you stream to a good hi-fi system, where you can actually hear music, try converting from whatever you have to Apple Lossless Audio Codec (ALAC). It only takes a moment and and does not destroy your original file, whatever it is.

I know actual missing data can't be recovered or even invented but it is possible to better interpolate lines of best fit between samples and it may be possible to do more with the dynamics and ambiance data.

If you convert a file you can try listening to a part of one version and then the same part of the other version a few times and make your own mind up.

I stream into around £8000 of hi-fi and I find that ALAC files give; a larger sound stage, increased dynamics, more definition overall, and generally more musicality. Putting it another way – simply better.

I've had the same question (and am still looking).

Could it be - The 256 ACC file is a compressed file, and that converting this file to a lossless file uncompresses the file for conversion to Apple Lossless. This saves the same data but now without the compression. Ergo - which increases the file size .... i.e. now LossLess.

My Apologies to those that have said the same thing, but maybe a bit more Techy.

Very simplified - The Size of the ACC 256 compressed file = X and when uncompressed to Apple Lossless the file size is now 3X (arbitrary ratio)

No new data - Just uncompressed.

The conundrum:

I too "believe", the ACC file converted to ALAC Apple Lossless file, sounds better when played. Wether real or not I prefer to convert the compressed file to a lossless file because my ears thinks it hears a LARGE difference and the difference in perceived quality pleases me i.e. sounds better to me..

I prefer to convert the compressed file to a lossless file because my ears thinks it hears a LARGE difference and the difference in perceived quality pleases me i.e. sounds better to me..

Good, then go for it.

Bud74 wrote:

I've had the same question (and am still looking).

Could it be - The 256 ACC file is a compressed file,

It is compressed but mainly it is smaller because bits are discarded, i.e.. no longer present in the file. They cannot be restored by converting it to anything.

and that converting this file to a lossless file uncompresses the file for conversion to Apple Lossless. This saves the same data but now without the compression.

Apple Lossless (ALAC) is compressed. That how ALAC file size is ~50%-60% of the original size with no loss of data.

No new data - Just uncompressed.

You cannot uncompress what is not there. AAC is missing large chunck of the original data.

Thanks Chris .... You are right .... the math is there like you say .... but .... Did a blind AB ... iMac iTunes 12 (Yosemite Beta 10.10) to appleTV to Emotiva XMC-1 and XPA 5... same settings ... same songs wifi streaming .... My son picked the converted Apple Lossless song 10 for 10 Processor must do something different with the Apple Lossless files.

I'm Done with this topic ... I can't make the equations balance ....