Apple Lossless Audio Codec Project becomes open source

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  • Reply 21 of 52
    Quote:
    Originally Posted by kaiser_soze View Post


    The true benefit of compressing audio in like manner as any other data is compressed, i.e., without using perceptual encoding that produces a bit stream from which the original bit stream cannot be recovered, is with archiving. For any large-scale archiving endeavor, the required amount of storage is reduced significantly relative to non-compressed audio encoding. But for playback purposes on portable devices, or even for at-home playback, it is silly. Of course there are always people who claim that they can hear things that they cannot actually hear, just as there are people who claim that they see flying saucers and bigfoot that they did not actually see. You do not have to experiment with audio encoding very long at all to realize that with perceptual encoding such as AAC, that the bit rate at which the sound is perceptually identical to the original is but a small fraction of the original bit rate. When you encode and listen carefully as you increase the bit rate one step at a time, you reach a point where there is almost not perceptual difference between the two bit rates. Then go a step or two higher, to where you cannot hear any difference whatsoever. Then for good measure, go one step higher. At that point you are using a higher bit rate than what is needed in order for the sound you hear to be perceptually identical to the original, and that bit rate is still a small fraction of the bit rate using any non-perceptual encoding scheme. It is also a well-established fact that when encoding AAC at a bit rate way below the bit rate that you get with non-perceptual encoding, the measurable distortion that results is quite small in comparison to the distortion present in any loudspeaker or headphone. The situation here is much the same as it is with people who claim that they can hear differences in amplifiers, when the fact is that for any decent high fidelity amplifier, the degradation of the signal is orders of magnitude less than it is with even the very finest loudspeakers and headphones. Since the beginning of audio transmission people have claimed that they can hear things that they cannot actually hear. Non-perceptual encoding techniques for audio have a place in professional archiving of music, but for anyone not in that business, and who only has the need to encode audio for personal and home use, non-perceptual encoding of audio has no relevance. It makes about as much sense as it would make to use a high-end supercomputer to browse the web.



    The paragraph. Live it. Love it. Use it.
  • Reply 22 of 52
    Quote:
    Originally Posted by solipsism View Post


    Where are you getting these FLAC files? How do you know the source isn't just a CD that someone ripped to FLAC 24bit 196KHz?



    HDtracks. Run by Norman Chesky, one of the most respected names in the music industry. He would not do that. While some High Rez downloads are better than others, many of these are incredible! Also check out Linn Records. The Dawn Langstroth Album Highwire is awesome at 24bit 96kHz!
  • Reply 23 of 52
    Quote:
    Originally Posted by tonton View Post


    The paragraph. Live it. Love it. Use it.



    Then there is the paragraph's ugly half-sisters: the colon and semi colon.
  • Reply 24 of 52
    MacProMacPro Posts: 19,728member
    Quote:
    Originally Posted by solipsism View Post


    Where are you getting these FLAC files? How do you know the source isn't just a CD that someone ripped to FLAC 24bit 196KHz?



    Yep given CD is 16 bit 44.1 Hz, I guess folks ripping higher are also upscaling Photoshop files from 72 d.p.i. to HD



    This is why I am looking forward to the iCould new system, am I correct to hope some stuff will be resampled from masters at a far higher rate ... not that I will probably hear it but I'd love to try on my Nightingale speakers and Quad amp for old times sake.
  • Reply 25 of 52
    Quote:
    Originally Posted by ConradJoe View Post


    Does anybody really use ALAC? Why not simply make iOS so it supports the popular lossless formats? Is ALAC superior to the other lossless formats?



    People who rip/mix/burn in iTunes can use ALAC and can't use other lossless formats. And iDevices can play ALAC.



    I'd love to see Apple support more CODECs in iTunes and for iDevices. A plugin architecture to allow third-party iTunes CODECs would be great, but I just don't envision Apple doing it. Adding new code, especially third-party code like FLAC, means they have to integrate and test and support that code. And third-party plugins can be a vector for malware. If iTunes misbehaves because of a customer-installed plugin or because of a bug in FLAC, Apple is going to be held responsible, and no amount of finger-pointing will help.



    As for superior, that depends on the criteria you're using. All lossless formats have the same sound quality, since the files decompress to the original input data. Perhaps one gets a better compression ratio over the other, or one supports a broader range of input formats, but someone else will have to provide that information.

    Quote:
    Originally Posted by ascii View Post


    This is the codec I used a few years ago to rip all my CDs before throwing them out (got sick of carting them from apartment to apartment).



    I hope you didn't actually throw them out. Those CDs are proof (should any obnoxious RIAA lawyer come a-knocking) that you actually bought the music and didn't download it. If moving is too much of a pain, pack them in boxes and don't bother unpacking, but I wouldn't throw them out.



    And if you give-away/sell the discs, and didn't destroy them, then copyright law says you lose the right to any copies you made, including those rips.
  • Reply 26 of 52
    Quote:
    Originally Posted by MidwestAppleFan View Post


    The question I have is will we now be able to download ALAC files in something more than 16bit 48kHz and will iTunes play them? Another person mentioned that CD quality is not all that great anymore and that is right. I download FLAC files at 24bit 96kHz which is really the start for High Rez sound now-a-days. A typical album will take up a little over a GiG of space at the rez but it is much better quality. There are more and more albums now available at an even higher 24bit 196kHz too.



    If ALAC is stuck at 16/48 then it is still only good for ripping old CD's.



    Yep! I've been converting my library to ALAC for a year or so now, so that I don't have to keep an "iTunes-friendly" mp3/aac version of my music alongside my lossless collection. Note that the iPhone only supports 44/48khz files, but I regularly play 24/96 and 24/88 ALAC files in in iTunes. ALAC even supports 6-channel ALAC files if you have surround music.



    The last thing iTunes needs now to be audiophile-friendly is ASIO/WASAPI output on Windows...



    Edit: Oh snap! Apparently iTunes does have bit-perfect output on Windows, you just have to configure it through the quicktime control panel:



    http://www.head-fi.org/t/444468/itun...bitperfect-out
  • Reply 27 of 52
    MacProMacPro Posts: 19,728member
    Quote:
    Originally Posted by MidwestAppleFan View Post


    HDtracks. Run by Norman Chesky, one of the most respected names in the music industry. He would not do that. While some High Rez downloads are better than others, many of these are incredible! Also check out Linn Records. The Dawn Langstroth Album Highwire is awesome at 24bit 96kHz!



    I was checking out this site upon reading your post. I don't see any explanation as to where or how they obtain access to original material to digitize at the HD rates. Any info on that?
  • Reply 28 of 52
    rcfarcfa Posts: 1,124member
    Quote:
    Originally Posted by ConradJoe View Post


    Why is Apple even bothering with this? Does anybody really use ALAC?



    Why not simply make iOS so it supports the popular lossless formats? Is ALAC superior to the other lossless formats?



    I don't have hard numbers, but all the lossless codecs are somewhere within the same ball-park in terms of compression ratio. Yes, some do 5-10% better, but in the age of cheap TB drives, that doesn't matter much.



    However, what the real issue is, whether an algorithm is optimized for compression ratio, compression speed, or decompression speed.



    I'd bet that ALAC is optimized for the latter, because you compress only once, and because battery (read fewer CPU cycles) is what's the scarce resource on portable devices.

    Lots of other lossless algorithms are optimized to squeeze the last bit of compression ratio out of a file, but they require a lot more CPU, thus drain mobile devices like an iPhone/iPad much faster of their power. Others were designed by people who were ripping large libraries, and were sick and tired of waiting, so they were optimized for compression speed, something Apple isn't worried about, because they consider it a one-time event, and a zero-time even (once/if) they make ALAC content available on the iTunes store.



    So, yes, indeed, ALAC may be superior to FLAC, MonkeyAudio, etc. etc. given the proper context, even if the resulting files are a few percent bigger.



    The only question is, why Apple waited so long making it open source. Maybe some patents expired or some legal sticking point was resolved. In any case, it's a highly welcome development. Now I wish, they'd also allow the use of the same algorithm in CAF files...



    To those questioning the use of ALAC for use in mobile devices due to lack of DAC quality: sure, but you don't create an iTunes library just for mobile use. Hooking up a high-end DAC (e.g. Metric-Halo devices) to a Mac, and then to a great amp/speaker combo beats just about any high-end stereo in terms of playback quality, and in terms of convenience, too.
  • Reply 29 of 52
    asciiascii Posts: 5,936member
    Quote:
    Originally Posted by shamino View Post


    I hope you didn't actually throw them out. Those CDs are proof (should any obnoxious RIAA lawyer come a-knocking) that you actually bought the music and didn't download it. If moving is too much of a pain, pack them in boxes and don't bother unpacking, but I wouldn't throw them out.



    Yes, I actually threw them out. I did not have to keep them as proof of innocence, since under the legal system I do not have to prove my innocence, others have to prove my guilt.
  • Reply 30 of 52
    If you're ripping your CD collection, then use ALAC. Here's why:



    1. With ALAC you can store cover art and all kinds of other info in the actual file. It's completely portable, which means copy the file (the track) to another machine and you've still got all the info. Album covers look great on big screens too. I don't think FLAC files store cover art or many kinds of info.



    2. You can always convert to lower quality, smaller files later if you need to.



    3. Storage isn't an issue. If it's your CD collection, you can afford to spend a few $£?¥ more for storage if necessary. Storage is cheap, especially compared to the amount you invested in that collection.



    4. ALAC will sound as good as your original CD. AAC/MP3 won't. (You don't get all that savings in space for nothing.)



    5. You can fit a lot of ALAC files on even the smallest of iDevices these days. Just resync when you're tired of the many hours of music they provide. They sound great when output to good audio systems too. My car rocks with my iPhone, and even my 128 kbps AAC-loving kids can tell the difference.



    If AAC or MP3s and cheap earbuds are your preferred mode of listening then this advice doesn't apply to you. If you can't hear the difference between a good original recording and a compressed version of that recording, then this doesn't apply to you either. Otherwise, go with ALAC and you won't regret it.
  • Reply 31 of 52
    Quote:
    Originally Posted by digitalclips View Post


    Yep given CD is 16 bit 44.1 Hz, I guess folks ripping higher are also upscaling Photoshop files from 72 d.p.i. to HD



    This is why I am looking forward to the iCould new system, am I correct to hope some stuff will be resampled from masters at a far higher rate ... not that I will probably hear it but I'd love to try on my Nightingale speakers and Quad amp for old times sake.



    The Photshop analogy is not a good one. Yes if you took the CD and made a High Rez FLAC file of it, it would not sound better. But that is not what the recording people do. When making a High Rez copy of the album, the master tape that was used in the original recording session is hauled out which means for most music before 1980 was an analogue tape and after that should be a higher resolutions digital master tape. The audio is converted using modern equipment that can go up to above 24bit 176kHz, is sometime remixed, and then made available for purchase.



    The better analogy is that what is happening is similar to taking a World War II photograph and scanning it with a good 1985 scanner, then scanning that same photograph with a good 2011 scanner. Which digital copy do you think will look better?



    If a High Rez album sounds bad, it is often the original sound engineer did a poor job to begin with. In that case, a High Rez file only makes the poor work stand out even more.
  • Reply 32 of 52
    cnocbuicnocbui Posts: 3,613member
    Quote:
    Originally Posted by John.B View Post


    The complaint I've heard from a friend with audiophile-itis is that the D/A converters in most PMPs (iPods included) aren't really good enough to benefit from lossless audio.



    They are wrong. I recorded the output from my 3rd gen iPod classic and the output from my well regarded CD player and spliced bits of the two recordings together. When you play back the file, no one I have encountered can tell the difference between the sections.



    I did the same for 224 kbps AAC vs the uncompressed original. Despite posting the file on the internet several times, no 'Audiophile', or anyone else, has ever been able to distinguish between the sections. kaiser_soze speaks the truth.



    As for hearing a difference between 16 bit and 24 bit recordings
  • Reply 33 of 52
    Quote:
    Originally Posted by cnocbui View Post


    I did the same for 224 kbps AAC vs the uncompressed original. Despite posting the file on the internet several times, no 'Audiophile', or anyone else, has ever been able to distinguish between the sections. kaiser_soze speaks the truth.



    The truth, perhaps, but only as it relates to him. As for your test, do you think it's possible people who know they hear the difference might not bother taking the test? I certainly wouldn't.



    You shouldn't feel upset about the fact that other people have different perceptions than you. Looked at positively, you can say that it makes life interesting. I, for one, am very sensitive to audible stimuli, but stick me in front of some paintings and I might as well drool as try to compare them to others.
  • Reply 34 of 52
    conradjoeconradjoe Posts: 1,887member
    Quote:
    Originally Posted by kaiser_soze View Post


    When you encode and listen carefully as you increase the bit rate one step at a time, you reach a point where there is almost not perceptual difference between the two bit rates. Then go a step or two higher, to where you cannot hear any difference whatsoever. Then for good measure, go one step higher.



    I have directly compared mp3s at 320 to .flac encoded audio, and the degree of difference surprised me. It was very clear even on my little computer sound system.



    Which bit rate do you consider "good enough" so that the differences are not audible?
  • Reply 35 of 52
    conradjoeconradjoe Posts: 1,887member
    Quote:
    Originally Posted by digitalclips View Post


    I was checking out this site upon reading your post. I don't see any explanation as to where or how they obtain access to original material to digitize at the HD rates. Any info on that?



    I got curious, so I took a look. I found this in the Rolling Stones Beggar's Banquet description:





    "Many years of research went into locating the original mono and stereo analog tapes that would be used in ABKCO's Rolling Stones Remastered Series. That research revealed a treasure trove of first generation tapes - true stereo masters from The Stones' 1964 Chess Studios sessions including the unedited version of "2120 South Michigan Avenue," Beggar's Banquet at its correct speed and Let It Bleed with splicing that indicates that the original intention was to leave little spacing between each cut.



    For the analog to digital transfers, vintage reel-to-reel tape machines were utilized - a modified Ampex 351 with original tube electronics (full track mono and two track stereo) and an Ampex ATR-102 modified with Aria Discrete Class-A Electronics (full track mono and two track stereo). A Sonoma DSD digital audio workstation was the chosen high resolution format and Meitner Design ADC8 and DAC8 MKlV converters were used for the conversion process. Cables used were the cryogenically frozen type supplied to us by Gus Skinas of Super Audio Center. Gus also provided much guidance to Jody Klein, Steve Rosenthal and myself for our first time use of DSD technology. For this HD Tracks release, the Bob Ludwig mastered DSD files were converted to both 176.4kHz and 88.2kHz high resolution PCM with Weiss Saracon conversion software."





    I didn't look at anything else, but I might.
  • Reply 36 of 52
    cnocbuicnocbui Posts: 3,613member
    Quote:
    Originally Posted by joeblowjapan View Post


    The truth, perhaps, but only as it relates to him. As for your test, do you think it's possible people who know they hear the difference might not bother taking the test? I certainly wouldn't.



    Actually, it is a truth that relates to most people - as verified by the community at Hydrogenaudio.org, where a lot of codec testing has been done involving quite a few people.



    Quote:

    You shouldn't feel upset about the fact that other people have different perceptions than you. Looked at positively, you can say that it makes life interesting. I, for one, am very sensitive to audible stimuli, but stick me in front of some paintings and I might as well drool as try to compare them to others.



    I am not upset at all. I actually derive amusement from the spectacle of naked Emperors admiring their new and expensive clothes.
  • Reply 37 of 52
    conradjoeconradjoe Posts: 1,887member
    Quote:
    Originally Posted by joeblowjapan View Post


    You shouldn't feel upset about the fact that other people have different perceptions than you. Looked at positively, you can say that it makes life interesting. I, for one, am very sensitive to audible stimuli,



    I know people who deny that there is any difference in flavor between instant coffee and freshly roasted, freshly ground and freshly brewed coffee.



    I believe that they are unaware or unable to tell the difference. That does not mean, however that no differences exist. Different people have different abilities to judge the way things taste.



    I also think that different people have different abilities to determine the way things sound and look. For example, a car buff will judge the paint job on a restored roadster with a discerning eye, while the average Joe would be unlikely to spot various defects.



    Additionally, somebody who has no idea what good audio is like may well have trouble discerning it when they hear it.



    Indeed, IMO, few people care much about quality. Other factors, such as convenience, are more important to them.
  • Reply 38 of 52
    Quote:
    Originally Posted by cnocbui View Post


    Actually, it is a truth that relates to most people



    "Most" is a step down from "all." And I think it's probably true that most people can't hear subtle differences.



    Quote:
    Originally Posted by cnocbui View Post


    I am not upset at all. I actually derive amusement from the spectacle of naked Emperors admiring their new and expensive clothes.



    Hmm. Well, enjoy yourself.
  • Reply 39 of 52
    Quote:
    Originally Posted by MidwestAppleFan View Post


    HDtracks. Run by Norman Chesky, one of the most respected names in the music industry. He would not do that. While some High Rez downloads are better than others, many of these are incredible! Also check out Linn Records. The Dawn Langstroth Album Highwire is awesome at 24bit 96kHz!



    no joking! the audio quality of files from hdtracks is amazing.
  • Reply 40 of 52
    cnocbuicnocbui Posts: 3,613member
    Quote:
    Originally Posted by joeblowjapan View Post


    "Most" is a step down from "all." And I think it's probably true that most people can't hear subtle differences.



    The word 'all' does not appear in my post.



    Quote:

    Hmm. Well, enjoy yourself.



    If you want me to believe your hearing is better than mine, or that of the people who have been unable discern a difference, you can always prove it.



    I would be happy to post either or both of the files mentioned, you can then listen to it/them and get back to us with the times at which the sources change.
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