High Efficiency AAC

Posted:
in iPod + iTunes + AppleTV edited January 2014
I've seen a few references to this but finally just read an explanation of what it is:

Quote:

The High Efficiency AAC Profile (HE AAC) is a combination of the MPEG-4 AAC Low Complexity (LC) Object and the MPEG-4 Spectral Band Replication (SBR) Object; HE AAC can deliver coding gains of more than 40 percent compared to MPEG-4 AAC LC.





HE AAC enables the delivery of 5.1 surround sound at 128 kbps, consumer-grade stereo at 48 kbps, and excellent quality stereo at 32 kbps or below. The coding efficiency of HE AAC enables new opportunities for optimized audio at low bit rates that are unprecedented, for applications in digital broadcasting, mobile multimedia, and Internet services.





HE AAC also enhances the quality of AAC by enabling 96 kHz coding with a nominal bit rate of 128 kbps. Moreover, 96 kHz HE AAC bitstreams can be played in legacy AAC decoders with a 48 kHz result.



http://www.vialicensing.com/products/HE_AAC/



This sounds pretty impressive. Imagine getting 5.1 sound at the same 128kbps rate that the iPod supplies stereo. We don't all have flying cars yet but I'll be happy with a 5.1 iPod.



Has anyone been testing any beta versions of this? Is it as nice as they claim? Does it take a lot more computer power to decode?

Comments

  • Reply 1 of 15
    hmurchisonhmurchison Posts: 12,129member
    I think NERO has been doing HE AAC for a while now. Apple should be eventually offering the choice hopefully by iTunes 5.



    HE AAC would be great for streaming audio around the house wired or wirelessly.
  • Reply 2 of 15
    kickahakickaha Posts: 8,760member
    I dunno, I'd hate to wear six speakers on my head... 5.1 on an iPod?? Hee.



    HE-AAC isn't designed for something as simple as an iPod - it's for HD level production.
  • Reply 3 of 15
    shetlineshetline Posts: 4,695member
    If Apple were simply to use 128 mpbs HE AAC for plain-ol' stereo, it sounds like we might get a nice increase in sound quality for the same bit rate, making iTMS purchases more appealing. (Not that I haven't purchased a fair amount of iTMS music as-is.)
  • Reply 4 of 15
    So it appears that this new version of AAC will allow even better sound quality at lower bitrate along with support for 5.1 surround sound.



    This is great of Apple to support this. If they do use this as the new codec for iTMS, what will they do with all the music they have encoded in the current version of AAC?



    Mike
  • Reply 5 of 15
    dfilerdfiler Posts: 3,420member
    Unfortunately, I don't think the record labels are interested in higher fidelity sound. If they were, we'd all be listening to something higher-def than redbook.



    Doublely unfortunate this is. iTMS could conceivably rip straight from studio DAT to higher than CD fidelity HE AAC.
  • Reply 6 of 15
    I agree dfiler, the biggest problem is licensing, not technology. However, this may point to life after the CD. New groups, groups with smaller audiences might choose to not produce a CD. A college symphony orchestra, for example, might release and sell a production in surround sound at a higher bit rate and have it only available on the web. Similarly with some other groups who are more concerned about producing a high quality work than locking down the digital rights. The next few years will be very interesting in this regard.
  • Reply 7 of 15
    hmurchisonhmurchison Posts: 12,129member
    aacPlus demolishes MP3 at 24kbps



    Wow I'm impressed. I could literally see a 1GB flash memory working now that aacPlus could sound acceptable at say 48kbps.
  • Reply 8 of 15
    Quote:

    Originally posted by dfiler

    Doublely unfortunate this is. iTMS could conceivably rip straight from studio DAT to higher than CD fidelity HE AAC.



    not unfortunate for itms though. imagine if they could say that a downloaded album from itms is HIGHER fidelity than listening to a store-bought cd.
  • Reply 9 of 15
    Quote:

    Originally posted by Kickaha

    HE-AAC isn't designed for something as simple as an iPod - it's for HD level production.



    Not really, it's for <128 kbps encodings (internet-streaming etc)



    LC-AAC will continue to be the standard above 128 kbps
  • Reply 10 of 15
    This could be a part of the rumored Flash iPod. If HE-AAC could provide reasonable fidelity at roughly three times the compression level of 128kbps songs then a 1GB iPod is more in line with the philosophy of the iPod (carry all or most of your music with you). If you are running or performing other activities you don't really need ultra high fidelity.
  • Reply 11 of 15
    kickahakickaha Posts: 8,760member
    Quote:

    Originally posted by Sopphode

    Not really, it's for <128 kbps encodings (internet-streaming etc)



    LC-AAC will continue to be the standard above 128 kbps




    By golly, you're right. I got HE-AAC and HD-AAC confused.
  • Reply 12 of 15
    HE-AAC is like a low gear, it lets you make the most of what you put in at a certain low range of speeds/bitrates. But that doesn't make it 'better' than a high gear overall, just more appropriate at certain ranges, and particularly not at higher speeds/bitrates (128kps and up) where it is inappropriate.



    The 5.1 surround is a totally separate idea, which I believe is already present in Tiger builds of quicktime (unlike HE-AAC). The only reason it gets mentioned is that 3 times as many sound channels needs 3x the bits so you need something like HE-ACC for 5.1 at 128kbps (i.e. an average of ~20kbps per channel).
  • Reply 13 of 15
    aquaticaquatic Posts: 5,602member
    Quote:

    I dunno, I'd hate to wear six speakers on my head... 5.1 on an iPod?? Hee.



    They have surround sound headphones. Haven't used them personally though so not sure how well they actually work.
  • Reply 14 of 15
    Quote:

    Originally posted by neutrino23

    This could be a part of the rumored Flash iPod. If HE-AAC could provide reasonable fidelity at roughly three times the compression level of 128kbps songs then a 1GB iPod is more in line with the philosophy of the iPod (carry all or most of your music with you). If you are running or performing other activities you don't really need ultra high fidelity.



    Yes, and this could be the "catch" and the "reason" for Apple to do a lower capacity (NOTE: I think the storage technology is irrelevant to most consumers) iPod (iPod Micro?)



    Apple has been very astute at making products different enough (iPod and iPod Mini and iPod Photo) that sometimes it is hard to decide which one you want...oh heck I'll just get them all! ;-)



    iPod Micro (or whatever) might use this new encoding (probably converted on the fly)...to allow more music to be stored.
  • Reply 15 of 15
    this is awesome, i can't wait!!! even better quality at smaller file sizes, this rocks my world!
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