iPod AAC Audio Coding, 320kbps ?

Discussion in 'Macintosh Computers' started by SteveCH, Oct 17, 2003.

  1. SteveCH macrumors newbie

    Joined:
    Oct 17, 2003
    #1

    Hello Guys

    I had some doubts and I hope someone could help me to clarify them
    • I read in several sites the rumors about a possible coding of 192kbps with the new release of iTunes
    • As I understood iTunes already supported AAC coding till 320kbps (selecting "custom")
    • Given that I could code my songs in AAC 320kbps .. is iPod able to play them ?
    • why, then, these rumors about "only" 192kpbs ?


    Steve, stefano.ortelli@philips.com
     
  2. arn macrumors god

    arn

    Staff Member

    Joined:
    Apr 9, 2001
    #2
    Well,

    the rumors were that the iTunes Music Store would be giving us higher encoded AACs. However, iTunes Music Store still gives us 128kbps encoded AACs.

    The iPod will play AAC up to 320Kbps.

    So you can encode them yourself at that bitrate (from CDs)... but you won't be able to fit as many on your iPod.

    arn
     
  3. Dreadnought macrumors 68020

    Dreadnought

    Joined:
    Jul 22, 2002
    Location:
    Almere, The Netherlands
    #3
    I second that!

    It's just a waste of harddiskspace to encode a cd even higher then 192 kbps AAC. The cd quality is not even that high and if you re-encode songs higher, the quality doesn't get better!
     
  4. WinterMute Moderator emeritus

    WinterMute

    Joined:
    Jan 19, 2003
    Location:
    London, England
    #4
    Well, being as AAC is a data compression system, ANY rate is going to be inferior from uncompressed PCM audio from a CD, but the file sizes are much bigger to reflect the increased data rates.

    I find 160Kbps AAC to be sonically superior to 320K MP3, ad listening through a pair of iPod earbuds means it really doesn't make much difference either way.

    We've conducted listening tests on various codecs at many rates, and AAC and Ogg Vorbis come out as subjectively superior on flat studio monitoring. MP3 and WMA lag well behind, generally needing much higher rates to come into contention.

    192 AAC is plenty good enough, 160 is fine, all you have to do is think about the quality of your delivery systems.
     
  5. Catt macrumors member

    Joined:
    May 21, 2003
    Location:
    London, UK
    #5
    Sorry to hijack the post but I have a couple of questions related to AAC and encoding rates in general.

    At the moment all the songs on my iPod are encoded at 256Kbps in MP3 format.
    Does it take more processing power for the iPod to play higher bit rate tracks? and if so would this have an effect on battery life?

    Regarding ACC: Minidisc players play back ATRAC files encoded at 292Kbps (or around that) is an AAC audio files rated at 256Kbps going to be comparable in quality to this? I ask because I still notice a gulf in quality between 256Kbps MP3s and Minidisc files - with ATRAC being superior.

    I use Sony E888 Headphones which have quite a good dynamic range.

    I would update all my MP3s to AAC audio but I use Windows ME and so can't easily do it as iTunes isn't compatable; but I hope to get a new laptop soon :)
     
  6. WinterMute Moderator emeritus

    WinterMute

    Joined:
    Jan 19, 2003
    Location:
    London, England
    #6
    There's no power issue in the codecs, it's just software.

    To my ears, AAC is a much more musical codec than MP3 at a much lower rate, I encode at 160Kbps for the iPod, and I think that sounds better than 320kbps MP3, I think the minidisc may have the edge over a monitor system, but not headphones. We have done subjective tests in studio conditions at the Uni, and AAC cameout well, as I mentioned before.

    You can now use iTunes on your PC, obviously.

    Try the AAC codec, not only does it sound better, but you get half your disc space back at 160.
     
  7. Catt macrumors member

    Joined:
    May 21, 2003
    Location:
    London, UK
    #7
    Unfortunately I can't because iTunes For Windows is only compatable with Windows XP and Windows 2000, and unfortunately I run Windows ME :(
     
  8. WinterMute Moderator emeritus

    WinterMute

    Joined:
    Jan 19, 2003
    Location:
    London, England
    #8
    OK, yeah, point taken, although there is an AAC player for windows here:

    http://www.mpeg.org/MPEG/aac.html#faqs

    I don't know wether it supports ME though.
     
  9. benixau macrumors 65816

    benixau

    Joined:
    Oct 9, 2002
    Location:
    Sydney, Australia
    #9
    i encoded all my songs (both MP3 and since iT4, AAC) at 160Kbps even though 128 was all that was recommended. Reason: I wanted to encode better than CD quality so that i could hopefuly not loose anything truly noticeable from my logitech 2.1s.

    At a loud volume i can easily hear the defects int he MP3 codecs andd this is not speaker distortion. AAC does not have this at all and i can barely hear the defects during the silence.

    Its all simple - AAC requires more power to encode (not decode) and with todays processors it is relatively easy to get away with minimal diference in encoding time.

    BTW - what format does the iPod store its voice recordings in?
     
  10. arn macrumors god

    arn

    Staff Member

    Joined:
    Apr 9, 2001
    #10
    WAV (uncompressed)

    arn
     

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