iTunes store music quality. Possible Apple bug or oversight...

Discussion in 'Digital Audio' started by chrisworld, Jan 14, 2012.

  1. chrisworld macrumors member

    Joined:
    Nov 14, 2006
    #1
    Hey all. I wanted to get some input on this as it's been boggling me a bit. Let me first explain that I know how digital audio works, I know the formats, I know what lossy and lossless is, I know how they encode, how they work..all that stuff. I am highly biased towards AAC for lossy implementations but I know that AAC is the successor to-and simply performs better than mp3 in more ways than a few. AAC is also supported on almost any audio platform you can imagine just about now. So nice to see mainstream finally realize that the change was welcome.

    Before I continue with my post and what it's really about, I'm NOT bashing Apple or the iTunes store, I'm just curious and would like to point out that there are a few songs that seem to be affected strangely with poor mastering or a bad transcode rather than a full lossless to AAC re-encode.

    Ok now I'll continue.

    -----

    I'm not happy with a [small handful] of songs on the iTunes store. iTunes Match really woke me up to this, but I already knew it with a song or two. On my computer... If I listen to an Apple Lossless song in it's original super-quality glory - I enjoy it. Being so biased to the best lossy format on the other hand, I can listen to songs as low as 128kbps on AAC only and still pick out how superior it is to mp3 and notice how audibly close it is to lossless or average to good equipment, but I prefer AAC 192 and usually settle with 256 for lower capacity mobile devices like my iPod.

    What does this have to do with the iTMS?

    Technically speaking of course - We know that the iTunes store is supposed to offer music in the form of digital audio files encoded at 256kbps AAC. When apple made the change, they said they were offering music at a higher bitrate (or "iTunes Plus" to make it sound grand to less technologically-knowledgeable folk) and that it would satisfy users with a song that was closer to the original recording than the previous 128kbps AAC files from before.

    What I want to know is why do the songs in my library at ALAC or 128-320 AAC still sound better than the affected song from the iTunes store? Even more simply put, 256 vs 256, they still differ and mine still wins. I can compare only a few more (less than 5 of my library's songs were affected) songs now because of iTunes match. I can encode an ALAC to 256kbps AAC, and pull a [matched] 256kbps AAC from the one available on the iTunes store. Now even though I've noticed the difference even in riffs out of the song preview from the iTMS, the difference is still obvious here too when compared side-by-side.

    What you have to do convert both to WAV and put them in an audio editor and then invert one. If there is ANY sound, then the audio files differ. This was done before by a user I can't remember the name of on ethier Mac Rumors or a different forum, but credit goes to him, if he reads this, he knows who he is. He did it to determine if a FLAC/AIFF/WAV and ALAC were the same. They were. You can also compare a lossy to the original lossless this way to determine how much data is thrown away. I didn't need to perform this test with out subject songs because it doesn't take a rocket scientist to hear bad compression artifacts in an audio file.

    The iTMS version if it's a song that was affected (which is supposed to be "closer to the original recording") aka. CD to 256 AAC sounds like it has major wet/swashy artifact sounds all over it. Vocals, cymbals, guitars.. it's all affected. Why? Was this an accident, or did apple justify that some songs (namely the metal genre) do not need to be re-encoded from lossless because they are already swashy enough? Yes, the affected songs are rock/heavy metal etc... The artifacts are still an obvious sound between the two but even for non-audiophiles like myself, the obvious artifacts ara put-off and to listen to the affected songs on my ipod (and soon my new 4s) I had to put my versions in an app like Goodreader if I wanted to listen to them without crappy artifacts.

    After re-downloads the first time around, I've deducted enough evidence to know that it wasn't a botched download. Some of the songs even sound this way in the previews. Overall though, the amount of songs I've noticed affected was less than 10, it's HIGHLY negligible. It has to be an oversight on Apple's end. As big as Apple is and has amazing services for their user's, I hardly, HARDLY imagine that Apple botched and transcoded songs so only the bitrate would show higher but never re-encode from Lossless. There are too many hardcore audiophiles to get on Apple's nerves for them to crap on music enthusiasts like this.
     
  2. TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #2
    What recordings in particular are you talking about? A lot of the times the songs sold on the Apple Store could be digital remasters if older recordings, which are usually a step back in terms of overall audio quality.

    You can take the files and look at their waveforms in audacity to compare contrast their dynamic range and/or inverting them to see if there's any differences.

    Also, it also could be that if the original recording was bad to begin with, a higher quality aac file will only bring out said bad recording. Washy/underwater effects is a tell/tell sign of compressed and distorted treble.
     
  3. Macman45 macrumors demi-god

    Macman45

    Joined:
    Jul 29, 2011
    Location:
    Somewhere Back In The Long Ago
    #3
    Hello, First and for most AAC is by no means lossless. As an eductcated
    individual you will understand that you can not regain what is transposed.


    IE: Rip a DVD / CD and use a decent audio package top, not bottom.

    In other words, you can not regain what is lost in original encoding.
     
  4. chrisworld thread starter macrumors member

    Joined:
    Nov 14, 2006
    #4
    Nowhere did I say in my post that AAC was lossless or that quality could be regained. I think you need to re-read.
     
  5. Zoddino macrumors member

    Zoddino

    Joined:
    Jun 27, 2010
    #5
    Remember that the AAC you have ripped by yourself come from CDs, instead for iTunes Store they use often masters. Especially lately I don't know if you have noticed the phrase "Mastered for iTunes" for many new albums such as Coldplay, U2, Pink Floyd ect. They're specifically mastered for iTunes with the new itunes producer program Apple released, which accepts 24/96 input original files. So yes, they're different than the ones you rip from cd, they come directly from the original studio files o different masters.
     
  6. AlanShutko macrumors 6502a

    Joined:
    Jun 2, 2008
    #6
    I've occasionally gotten emails from iTMS letting me know I can redownload a file because they've fixed some quality issue. So it seems that they are listening to feedback on file quality.

    I'd suggest contacting them about the specific tracks and seeing if there's a way for them to fix it.
     
  7. chrisworld thread starter macrumors member

    Joined:
    Nov 14, 2006
    #7
    But why would some "mastered for itunes" songs sound "worse" than a lossless aiff file from a cd? We're already passed lossless/aac stuff - I don't notice a difference between AAC and Lossless - it's just my ears, i know AAC is lossy but it's not only worlds ahead of mp3.. it's universes ahead.. Now that were past all that, I just don't get why some songs sound like they have a choppy/swashyness to them coming from the itunes store. That doesn't sound very mastered to me... it sounds like quality control gone cheap-side.
     
  8. PAPO macrumors 6502

    Joined:
    Aug 24, 2009
    Location:
    Australia
    #8
    if you can't here the difference between AAC and lossless, you mustn't be using very good headphones, when I put my good headphones or speakers on I can honestly hear the artefacts caused by the compression and it's horrible on my iPod headphones or my laptop headphones yes they sound similar but if those are your benchmarks your doing something wrong
     
  9. TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #9
    And pray tell what headphones and equipment are you using? :rolleyes:
     
  10. PAPO macrumors 6502

    Joined:
    Aug 24, 2009
    Location:
    Australia
    #10
    Mbox2Pro coming out of my MBP using AKG Q701's but there is still a noticeable quality difference with my Q460's straight out of my MBP
     
  11. TMRaven macrumors 68020

    TMRaven

    Joined:
    Nov 5, 2009
    #11
    I've a pair of Denons and Beyerdynamic lined out from a Music Streamer II and Little Dot for my headphones, and I'd be hard-pressed to tell the difference between a well recorded AAC at 320kbps and the same recording at lossless bitrate.

    It really isn't as much about the equipment as it is about how trained your hearing is.
     
  12. aristobrat macrumors G4

    Joined:
    Oct 14, 2005
    #12
    Does Apple even get involved with transcoding? I thought Apple always required the content providers to deliver the music in the formats that they wanted for the iTunes Store.

    http://www.apple.com/itunes/content-providers/music-faq.html
     
  13. PAPO macrumors 6502

    Joined:
    Aug 24, 2009
    Location:
    Australia
    #13
    well, I guess my hearing is better than I thought it was... and to be honest I wasn't exactly humble about my hearing :p
     
  14. davidjearly macrumors 68020

    davidjearly

    Joined:
    Sep 21, 2006
    Location:
    Glasgow, Scotland
    #14
    That's also because there is very minimal difference between 320kbps AAC and Lossless, despite what the other poster thinks he can here. What is more important is the source of the audio and the amount of compression applied in the studio.
     
  15. bwhli macrumors 6502a

    bwhli

    Joined:
    Jan 9, 2012
    Location:
    Boston, MA
    #15
    I know some music licenses allow one transcode, and if the first one was done a long time ago before the current 256kbps standard on iTunes, then Apple technically can't change the format because they are not allowed to. Maybe this has something to do with it as well. Though...some albums are really poorly mastered.
     
  16. spacepower7 macrumors 68000

    Joined:
    May 6, 2004
    #16
    It's all subjective. I can find 1000+ posts declaring that the mbox2pro dac's suck compared to higher priced gear. It's music, enjoy it.
     
  17. PAPO macrumors 6502

    Joined:
    Aug 24, 2009
    Location:
    Australia
    #17
    well I needed something for pro tools, and it's better than anything built into my laptop (surely...) so when I'm up for some serious listening that's what I use... I'm considering a headphone amp but I'm not in any rush 'cause the mbox 2 pro still lets me hear A-LOT
     

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