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MP3...in Surround Sound 247

Posted by Hemos
from the THX-We're-Coming-For-You dept.
A number of people sent in the latest news from the fine folks at Frauhofer that they are expecting to have surround sound working for MP3s by July. The details are pretty sketchy in the article, but supposedly it won't be much more space per MP3s, and existing players will work with it.
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MP3...in Surround Sound

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  • Ipod? (Score:3, Interesting)

    by Enze6997 (741393) * on Monday March 22, 2004 @09:08AM (#8633106)
    Whats this mean for the Ipod? Firmware upgrade? I was going to buy but if I should wait for a 4th gen Dolby 5.1 edition to come out I will.
    • Re:Ipod? (Score:5, Funny)

      by Anonymous Coward on Monday March 22, 2004 @09:20AM (#8633181)
      You should wait for the iPod Micro Edition. So small it fits in your anus and uses a methane-powered fuel cell. Oh, and it comes with a 64GB solid state memory chip and supports 6.3 Dolby Surround Extreme.

      An optional accessory allows the device so play through bone conduction so that you don't have unsightly earphone wires coming out of the back of your pants.
    • Re:Ipod? (Score:3, Interesting)

      by millahtime (710421)
      "Whats this mean for the Ipod? Firmware upgrade? I was going to buy but if I should wait for a 4th gen Dolby 5.1 edition to come out I will."

      As far as ipod updates go it's fairly easy. ITunes will pull down updates when new ones are released and updated your ipod when it's connected. Not very difficult and apple is on top of their updates. Apple makes updates easy.
    • Re:Ipod? (Score:3, Interesting)

      by Fulkkari (603331)

      It would need a new connector, because you can only get stereo stereo from the iPod as far as I can tell. And how do you get surround sound from a pair of headphones with only with a left and right channel? Or am I missing something here?

      • Re:Ipod? (Score:3, Insightful)

        by tfreport (458641)
        Most of the people I know that have an iPod use it for more than a modern walkman. They also plug it into their car stereos or speakers in their living room. With high storage capacities, MP3 players and their like are used for more than simply walking around listening to music. I would assume that this could be used for those situations.
      • Binaural Explained (Score:5, Interesting)

        by BigBlockMopar (191202) on Monday March 22, 2004 @10:20AM (#8633579) Homepage

        It would need a new connector, because you can only get stereo stereo from the iPod as far as I can tell.

        For a surround output to an audio system, you would need a new connector offering at least 4 channels (Front L/R, rear L/R), line level. They'd probably make it straight-up 5.1, though.

        And how do you get surround sound from a pair of headphones with only with a left and right channel?

        Easily. Headphones have two channels (L/R), you have two ears (L/R). Your brain does some pretty heavy duty phase analysis to figure out where a sound is coming from. In fact, binaural recording is a technique where two microphones (L/R) are mounted on a form resembling the human head, but you need to wear headphones for the full effect.

        A portable device could either use 4 channel headphones (expensive, requires 4 amplifiers to drive them, would increase battery consumption) or could use a DSP integrated circuit to decode the surround sound channels, perform the phase analysis done by the human brain, and send this synthetic binaural signal to regular headphones.

        But it's still a lot of work for little payoff. Most of the use for surround sound in any form is movies. Music tends to be mixed to 2 channels from the perspective of a listener sitting in front of the stage, so I think its importance in a portable device primarily used for music is pretty limited.

        • I'll take a dozen. Oh, and throw a case of TCP frames in that order, too, OK?
          </sarcasm>

          Curiously, when you put two drivers inside the same can and seal it over a single ear, there is no opportunity to perform phase analysis. Not saying 4-channel 'phones don't exist (though Google doesn't seem to know of any)... nope, just saying the market is probably limited to people that buy penis enlargement pills from spamvertisments.

        • You could actually do it without modifying the case by putting a laser diode at the bottom of the headphone jack and coming up with a weird miniplug-optical plug. You could detect it by having an unusually high or low (or just a known) impedance on the electrical connections. Then you can just do dolby 5.1 output or whatever via optical SPDIF.
        • Of course, good binaural recordings (and good stereo recordings) are better at sound immersion than any 4, 5.1 or 7.1 setup you might make. After all, like you said, we only have two ears which process all the sound in the world. So all those extra channels become downmixed when they get to your ears.

          But you need a slightly different mix for binaural vs. stereo devices (due to differences in delays and placement of the drivers). And to produce a proper stereo soundstage, you need to be really careful ab
      • by Lumpy (12016)
        you are missing something here..

        you can get the origional dolby suround from only 2 speakers easily...

        the rear speaker is simply the positive lead from the left and right speaker into the rear speaker.

        I had surround sound for movies at home cince 1987 for basically free that way... today I use a real surround decoder, but the origional dolby spec followed the above.

        (note, most rear speakers today that are 5.1 surround are really that way also. it is rare that any surround sound decoder can send discreet
        • Now I know they're not known for making top quality gear but my sony claims to have discrete amplification and it's an old-ass cheapie. I originally had a really crappy teac which made no such claims, but I ditched it and got the sony... Assuming Sony didn't lie to me, it's not as rare as you imply. Unless you are counting the ultra-cheapies that you can pick up at target for a hundred bucks?
  • by Shinglor (714132) <luke,shingles&gmail,com> on Monday March 22, 2004 @09:10AM (#8633119)
    MP3 is an outdated CODEC, the only reason it's still in use is because of compatibility. If you start adding extra features that break compatibility people will just move to a better quality CODEC with the same features (and possibly more).
    • by AntiOrganic (650691) on Monday March 22, 2004 @09:12AM (#8633128) Homepage
      Read the article, stupid.

      Music encoded with the new system will work with older hardware and software MP3 players but the extras will only the surround sound when piped through a player that can do something with the extra information.
      • by Lord of Ironhand (456015) <arjen@xyx.nl> on Monday March 22, 2004 @09:19AM (#8633179) Homepage
        And meanwhile, the files will grow uselessly larger for other (read: most) people and slightly cracked players will finally break entirely.

        There are far better options around for multi-channel audio now.

      • by blorg (726186) on Monday March 22, 2004 @09:24AM (#8633208)
        Grandparent is essentially right. MP3 *is* an outdated codec, which is only still here because of it's universality (don't get me wrong - this is a big benefit). While these added features may not actually break the old standard, they do result in bigger files with no discernable benefit for the vast majority of people. If you want to examine the success of previous add-ons to the mp3 standard, take mp3-pro - it's not exactly all over the place. People will take standard mp3 for it's universality, and choose a superior codec (AAC, OGG, MPC, whatever - even WMA) when they aren't concerned about compatibility.
        • by AntiOrganic (650691) on Monday March 22, 2004 @09:30AM (#8633237) Homepage
          Not to mention how the method of adding pretend "surround sound" that they're proposing is retarded.

          For what it's worth, MP3Pro also wasn't really backwards-compatible, even though it claimed to be. In a format that didn't support the extensions, it cut off the entire high end and it sounded like absolute shit. It remains to be seen if the same issue will be seen in these surround MP3s, but if it really doesn't add too much, like the article is implying, I don't imagine it will be a cataclysmic failure.

          Besides, there aren't that many surround-sound audio CDs to rip yet, so something like this wouldn't gain in popularity until a more popular codec has already superseded it. I wouldn't worry about it gaining any type of dominance.
        • as soon as all these companiesthat made my mp3 hardware release firmware upgrades to play ogg I'm there...

          but I dont see my audiotrons, my pioneer car stereo, and my portables getting ogg support in the next 10,000 years so Mp3 it is.. and the same stance is held by millions of other consumers that also shelled out gobs of cash for mp3 enabled devices..

          I dont care what is better, I care about what works in my equipment. if they come out with blue-ray uber DVD players tommorow almost 90% of the population
          • There's no reason blu-ray can't be backwards compatible, if you have to use a damned second laser to do it. This is not beta, this is not vinyl -> CD. The two standards can and will interoperate (at least, the new systems will support the old stuff to some degree) whether they tell you they will or not, because people will pay money for that shit.

            You're right about the utter lack of ogg support, and the fact that mp3 succeeds because it's everywhere and easy (and cheap) to get your hands on.

      • If you start adding extra features that break compatibility people will just move to a better quality CODEC with the same features (and possibly more).
      But the article makes it clear that the new Mp3s will play just fine in current software/hardware, they just won't be able to take advantage of the surround sound information. This isn't breaking compatability at all, in fact it's preserving it while adding new features.
    • As others have said, the codec does have backward compatability. I'm not sure I agree incidentally that MP3 is "out-dated": it's still, by far, the most popular format and codec out there and Fraunhoffer are making incremental improvements to keep it there (such as the subject of this article.)

      That's not to suggest that there aren't better codecs. There are. The alternatives are a lot better. But the most popular car engine in the world is the gasoline internal-combustion four-stroke engine, an inefficien

  • conversion (Score:5, Informative)

    by tomocoo (699236) on Monday March 22, 2004 @09:11AM (#8633121)
    You couldn't convert your mp3's to surround because the source is stereo... if you want surround just run it through PL2 for pretty good on the spot surround sound.
  • by Gavin Rogers (301715) <grogers@vk6hgr.echidna.id.au> on Monday March 22, 2004 @09:11AM (#8633125) Homepage
    I don't know why you'd need to change anything... I get surround sound right now with my ordinary stereo MP3s. It's called Dolby Pro Logic :-)

    • by Anonymous Coward
      I get the same thing with my 1970 stereo. I can control the positional audio with the Left/Right balance knob.
    • Re:New format? Why? (Score:3, Informative)

      by Bobman1235 (191138)
      I don't know why you'd need to change anything... I get surround sound right now with my ordinary stereo MP3s. It's called Dolby Pro Logic :-)

      Exactly right. Dolby Pro Logic works with regular stereo channels. If left and right are identical, it's the center channel. If they're exactly opposite (can't think of the "waveform" word for this) the sound goes to the rear channel. Otherwise they go to the front per usual. Other than making sure the sound is encoded in this way (which would take no extra "
      • My initial thoughts on this problem -- would an encoder "see" the extra information within a Dolby Pro Logic encoded track, and attempt to get rid of it since it's not necessary information? I think you'd probably see problems with this, at least at the low bit rates. I've never been inclined to try to encode a pro-logic recording -- most of them would be on VHS, and I have no use for that.
        • to a decoder that isn't aware of dolby's magic, it appears to be regular stereo sound. that's the beauty of dolby pro logic, its backwards compatible.

          to a decoder that is aware of dolby's magic, it can mathematically create the rear and center channels from the way the two standard channels are encoded. its actually very simple.

          FM radio is the same way, it wasn't always stereo. before the hi-fi days FM was mono and the stereo encoders were created in a way that made it possible to transmit one single a
          • Re:New format? Why? (Score:3, Informative)

            by Piquan (49943)
            But if the encoder throws out phase information, then surround gets thrown out too. I could see this happening in a FFT-based codec.

            FM radio is the same way, it wasn't always stereo.

            Yes, but to rebroadcast a stereo FM signal, you have to be stereo-aware. The idea behind Dolby PL is that copying equipment didn't need to be PL-aware. But back then, all the duplicating equipment would preserve phase. These days, it may get chunked, inverted, or have other icky stuff happen.

        • You are quite right, any lossy format will scrub out this information when too low a bitrate is used. Using variable bit rate will probably tend to erase it just from sections of a song. I am still using MP3 in spite of the fact that there are better alternatives, but I use it at 320kbps. It's true that makes the tracks take up a lot of space and that a lot of devices won't play them, but at 320kbps they sound so good that I can just re-encode them at 128 (or less) for crappy portable devices. Most of the t
      • And if you're not picky, and just want seperate rear left and right channels, go with DPLII.

        Does anyone know how Dolby Pro-Logic II encoding works?
  • by Threni (635302) on Monday March 22, 2004 @09:12AM (#8633126)
    So you can have over sibilant vocals in front of you, warbly underwater bass behind you, and audio artefacts moving in circles about your head... I can't wait!
  • Nothing to see here. (Score:5, Informative)

    by sokk (691010) on Monday March 22, 2004 @09:12AM (#8633133)
    Ogg Vorbis have had support [ogghelp.com] for this for some while.

    What I'm not sure of is if the support for "joint" surround is there. (Like joint stereo, only for surround)

    Who wants to use a proprietary sound format, when they can use a much more appealing open format.
    • by nacturation (646836) <(nacturation) (at) (gmail.com)> on Monday March 22, 2004 @09:35AM (#8633268) Journal
      Who wants to use a proprietary sound format, when they can use a much more appealing open format.

      MP3: Everything supports it, which is very appealing for consumers.
      OGG: Few products support it, not very appealing for consumers.

      This is the old VHS/BETA debate again. Each one has various advantages over the other, but MP3 has already won mindshare and, as a result, is ubiquitous. In the end, consumers don't really care that Apple has to pay Fraunhofer $1 (or whatever) for licensing iPod's MP3 tech instead of $0 for OGG. After all, you'll never see Apple advertising a regular iPod for $299 -OR- you can get an iPod which doesn't play MP3 for $298.
      • Nope. The new MP3 format is still in the lab. Nothing supports it. For the time being, measured by number of supporting devices, ogg has the lead in the surround sound stakes against MP3 (ie. 1 > 0).
        • When comp[aring ogg to mp3 maybe, but virtually any consumer who ever deals with surround sound there days will get it from a DVD in aac format.

          When a mp3 player with surround sound gets developed, on which peopel can also play back all their old mp3s, then that player will have an enormous advantage over ogg, regardless of how much earlier ogg had surround sound.

          I wonder tho, multi channel mpeg audio is not new, it has been done on mpeg layer 2, and that is in fact in use in many European DVD players.

          Fr
          • When comp[aring ogg to mp3 maybe, but virtually any consumer who ever deals with surround sound there days will get it from a DVD in aac format.


            I am not sure what you are saying here, but I am pretty sure that you mean .AC3 format not .AAC .
      • by Anonymous Coward on Monday March 22, 2004 @09:52AM (#8633371)
        Yes, MP3 still remains extremely popular, but it is showing its age, and it isn't doing so well in other, less high-profile areas.

        One of the places Ogg Vorbis has become surprisingly popular is in soundtracks for computer games. The no licensing fees must be one useful aspect, but there's also definite technological advantages such as better compression, more channels and - very important for sound effects and looped audio - arbitrary length samples.

        I was really impressed to discover that Halo for the PC uses Ogg Vorbis for all its sound, and it's published by Microsoft! It's not alone, either - if you've bought a PC game at all recently there's a good chance the audio's compressed with Ogg Vorbis.

        Is Ogg Vorbis successful? I'd say it was.
        • Unreal Tournament 2003 and 2004 also use Ogg Vorbis.
        • by Kjella (173770) on Monday March 22, 2004 @10:45AM (#8633867) Homepage
          One of the places Ogg Vorbis has become surprisingly popular is in soundtracks for computer games. The no licensing fees must be one useful aspect,

          No licencing fees doesn't mean just that. It also means no overhead like getting a licencing deal set up, signed, making sure it's paid on time, in right amount, used only in accordance with the terms and so on. I'm seeing this first hand how much time is spent fiddling.

          Just the process of going to someone with the authoroty to sign contracts and spend money in the company's name is wasting time, and time is money. That everyone, everywhere can use it for whatever is in itself probably worth as much as the licencing costs themselves.

          Kjella
      • This is the old VHS/BETA debate again

        No it isn't, and I wish people wouldn't keep bring that up. Any decent media player can play multiple formats, getting support for Ogg in a program is really really simple and free. MP3 and Ogg can and do co-exist quite happly.

        The same can't be said for BETA and VHS which are very different physically. There may have been a device that can play both, but I bet it cost a small fortune. It isn't easy to do. And this is why BETA failed.

        Ogg is everywhere, still a smal
        • Also, Beta was licensed out of existence by Sony, they wanted a cut of everything and that's simply not how you get your standard accepted. Apparently, you can't give ogg away. Well, you can, but it boggles my mind why people aren't implementing ogg in everything. Let's see, they come up with the software and give it away, but that's not enough, then they come up with a pure-integer implementation which I thought would surely be the watershed line, but people STILL aren't putting ogg support in their device
    • Who wants to use a proprietary sound format, when they can use a much more appealing open format.

      I do! Well actually, I still prefer AAC, but you'd probably try to make the same argument.

      As much as people bitched and moaned at the time, as far as I can tell the GIF tax never really hurt anyone. Likewise, it's hard for me to worry about MP3 not being free as long as my player of choice [apple.com] isn't costing me a cent.
    • > Who wants to use a proprietary sound format, when they can use a much more appealing open format

      The key word here is "use". Can I use ogg on my iPod? In my car mp3 player? Practically anywhere at all? No. This is news because it applies to something people like my Mum and Dad have heard of. I sincerely doubt that they are aware of OGG and FLAC.

      Outside of slashdot people don't care about open vs proprietary, "free as in speech", elegance of algorithms or having the source. Technology is an enabler, no
  • I thought... (Score:3, Informative)

    by Bluesman (104513) on Monday March 22, 2004 @09:13AM (#8633137) Homepage
    ...surround sound was encoded on the two stereo channels. At least I thought that was how it worked up until Dolby Pro-Logic wasn't the latest thing anymore and you had digital connections from the source to the AC-3 or Dolby Digital receiver or whatever. (I haven't kept up...)

    I just assumed that the surround channels were basically a diff between the right and left channel and the center was a sum.
    • Re:I thought... (Score:4, Informative)

      by daBass (56811) on Monday March 22, 2004 @10:07AM (#8633486)
      The system you mention is "Dolby Stereo". But "sum" and "diff" aren't the correct terms. Any signal that is in 100% phase on both left and right will end up in the center channel. Signals that are out of phase end up in the rear.

      Now "Dolby Stereo" sounds like it is, well, stereo. So the marketing department decided at some point that it should be called "Dolby Surround", which is fair enough. "Pro Logic" is "Dolby Surround" for use in home A/V amps, but with "Pro" electronics (logic). Another marketing term for the same thing.

      That system should work fine on any MP3. Stereo MPEG audio on DVDs (so not the Dolby Digital or DTS tracks) quite often have Dolby Stereo/Surround encoding on them as well.

      The truth is that the BBC article doesn't have enough information and I think "Surround" is used as a general term to indicate more than two channels of audio. So no way of knowing what they actualy mean.
  • by AtariAmarok (451306) on Monday March 22, 2004 @09:14AM (#8633143)
    Now, if only you can get MP3's to play in quad, and go KERCHUNK every few minutes, and my 8-track flashback to 1973 will be complete!
  • by Anonymous Coward on Monday March 22, 2004 @09:14AM (#8633146)
    Vorbis is also intended for lower and higher sample rates (from 8kHz telephony to 192kHz digital masters) and a range of channel representations (monaural, polyphonic, stereo, quadraphonic, 5.1, ambisonic, or up to 255 discrete channels)

    http://xiph.org/ogg/vorbis/doc/vorbis-spec-intro.h tml [xiph.org]
  • Surround? (Score:2, Informative)

    Isn't Surround Sound the technique of encoding 4 channels of audio (left, right, front, rear ("surround")) in 2 discrete channels, such as used by a lot of movies on TV? Since only 2 real channels are used, this was already possible using MP3.

    Maybe "multichannel" would be a more appropriate description.

    • Re:Surround? (Score:3, Informative)

      by Drakonite (523948)
      Isn't Surround Sound the technique of encoding 4 channels of audio (left, right, front, rear ("surround")) in 2 discrete channels, such as used by a lot of movies on TV? Since only 2 real channels are used, this was already possible using MP3.

      Maybe "multichannel" would be a more appropriate description.

      Surround sound is the technique of placing speakers around you so sound comes from all directions.

      While it is true that some encoding schemes (i.e. Dolby) work by combining the various channels into just

  • DRM (Score:2, Interesting)

    by Cackmobile (182667)
    Is this the release which includes DRM. Surround sound could be cool though.
  • Silly? (Score:5, Interesting)

    by Davak (526912) on Monday March 22, 2004 @09:17AM (#8633163) Homepage
    Fraunhofer reproduces surround sound by adding to MP3 encoding extra information that describes the spatial characteristics of the main audio track.

    If they are just adding information to the main track, why put that information in the file to begin with? Just let the user have a "spatial" encoder plug-in that jacks into winamp or whatever. Doing it this way increases the file size for everybody... people with and without surround systems.

    Surround information should not be "created." It should be ripped and converted from the original source.

    Before long we'll have the mp3 mess that we currently have with all the video codecs.

    Davak

    • That got scored insightful? There is no way in hell Fraunhofer would think of "creating" spatial information like those god-awefull annoying sounding "virtual surround" plugins for various media players and settings on cheap A/V systems. These folks are much smarter than that, you, or I for that matter.

      Truth is that there is not enough information in the article to tell what they are doing. My best guess is that they are multi channel enabling MP3s. So they would record all the discreet channels from a DTS
  • DRM? (Score:4, Insightful)

    by Seek_1 (639070) on Monday March 22, 2004 @09:18AM (#8633170)
    Hmmm... this might be a good time for then to try to 'enhance' the MP3 standard by adding in DRM as the various **AA's (damn them to Heck!) have been urging for years.

    I think I'll sit out on this one thank you very much. I like music and everything, but stereo is more than adequate for me (If I want 6 channel sound, I'll just watch a DVD...)
  • by iPaqMan (230487) on Monday March 22, 2004 @09:18AM (#8633172)
    Finally Frauhofer will catch up to the innovation that Microsoft made more than a year ago. (Oh the irony) Windows Media could do this since its last realease. http://www.microsoft.com/windows/windowsmedia/9ser ies/Gettingstarted/DemoCenter/AudioQuality.asp?pag e=6&lookup=AudioQuality

    Was MS first to have this technology for the mainstream consumer???
  • FooBar2000 already has plugin's available that can do this too...

    www.foobar2000.com for details.
  • Zaireeka! (Score:3, Funny)

    by Anonymous Coward on Monday March 22, 2004 @09:26AM (#8633222)
    Now you'll only need 2 computers to listen to Zaireeka [janecek.com] !
  • Some Additional Tech (Score:5, Informative)

    by Effugas (2378) on Monday March 22, 2004 @09:28AM (#8633229) Homepage
    Here's the deal.

    By far, the most popular algorithm in use for surround sound encoding is Dolby's AC3 (I can say this, because it's on pretty much every DVD, and nothing comes close to its penetration even in the audio space -- not even DVD-Audio). AC3 itself is a pretty fascinating codec; one of the more interesting things about it is that each additional channel requires less and less bandwidth to tack on. This is because there tends to be massive correlation between channels -- either the same sound is coming from multiple directions, or a sound is coming from one direction and all the others are silent, or some combination therein. AC3 encodes this quite efficiently, and thus gets really high quality surround sound in surprisingly few bits.

    I suspect they're engineering a similar mode for MP3 -- hopefully something a little nicer than Joint Stereo, which basically works by doing a mono mix and specifying which frequencies are louder in which channel. No, this doesn't work very well. Concievably, we could see something like VBR on a per-channel basis, but I suspect this would cause existing decoders to collapse. I do believe it's possible to place extra data between MP3 granules; I suppose they'll get their backwards compatible surround mode worked into there.

    --Dan
    • by mudrat (412407) <mudrat AT iafrica DOT com> on Monday March 22, 2004 @09:51AM (#8633364)
      I suspect they're engineering a similar mode for MP3 -- hopefully something a little nicer than Joint Stereo, which basically works by doing a mono mix and specifying which frequencies are louder in which channel. No, this doesn't work very well. Concievably, we could see something like VBR on a per-channel basis, but I suspect this would cause existing decoders to collapse. I do believe it's possible to place extra data between MP3 granules; I suppose they'll get their backwards compatible surround mode worked into there.

      That is precisely how MP3 mid side stereo mode works. It takes the sum of the channels (the common sounds) and encodes with a higher bitrate than the sounds that differ. Joint stereo is a mode where the encoder decides whether to use Mid-Side or true stereo for each frame depending on the stereo seperation. Joint stereo gives better results than true stereo at the same bitrate.

      The mode you describe (mono with frequency info) is Intensity Stereo which few encoders even support.
    • As the other poster mentioned, you are describing intensity stereo mode. Joint stereo and real stereo modes work as follows:

      Joint stereo does mid/side encoding. Basically, you can convert any standard left-right stereo source to mid-side with simple math. The mid channel is left+right, the side channel is left-right. Now the benefit here is that more of what we percieve as quality comes from the mid channel than the side channel. So, when we do M/S endocing, we spend more bits on the mid, and it is perciev
  • Anyone know how discrete the channels are? "Surround Sound" Codecs often do not support fully discrete channels. If I remember correctly, Dolby ProLogic is four channels encoded in two audio channels and doesn't support fully discrete surround channels. I think to a lessor extent this is also true of Dolby Digital (AC3) (Combines channels at frequencies above 15kHz), but DTS does support fully discrete surround channels (This is part of the reason why DTS uses more bandwidth than AC3). Anyone know if the
  • by Lord Kano (13027) on Monday March 22, 2004 @09:48AM (#8633350) Homepage Journal
    No one will give a flying fuck about MP3+DRM, but if they add it at the same time as multi channel surround sound support they might be able to get people to use it.

    LK
  • You basically have two ways to achieve this ; the most obvious, but also the most inelegant one being simply saving multiple tracks in the file. I think they will rather use a multiplexing algorithm dealing with phasis and frequency similarities between the tracks ; that's why it shouldn't be that space-consuming.

    But it is exactly what the Ogg Vorbis is working on. Please, don't adopt this standard ; I am sick of patents and licenses issues on video and audio codecs and algorithms. The industry will proba
  • WTF?! (Score:3, Insightful)

    by Anita Coney (648748) on Monday March 22, 2004 @10:07AM (#8633485) Homepage
    Why the f#ck do we need a PORTABLE surround-sound music format?!

  • Surround (Score:2, Informative)

    by robnauta (716284)
    Maybe there is confusion about the naming and what the article means exactly.
    Surround sound is the technique to make stereo come from different directions. Either using virtual surround by splitting by frequency range or using additional information, like Dolby Surround with its phase encoding.
    DTS and dolby digital 5.1 shouldn't be called surround, they are multichannel sound.
    Ogg and WMA 9 both support multichannel sound. Of course all stereo formats support surround (dolby) as long as the phase information
    • All stereo formats can also have their phase information reconstructed by Dolby ProLogic/ProLogic II as well. Granted, it's not as accurate as the original studio-encoded phase information, but it's "good enough" for most circumstances.
  • i dont get it... (Score:3, Insightful)

    by seven5 (596044) on Monday March 22, 2004 @10:33AM (#8633716)
    I don't see why they would put the time into their "teenager" codec to put surround sound support into it. Especially when mp3 is mainly used for music and isn't technically for video. Where as they could have spent the time to hammer out multichannel support for aac, so then mpeg4 would have multichannel support. So then they'd have a codec for video AND a codec used for just audio with multichannel support. The only thing i see this good for is Xvix and Divx videos. While these can be encoded with AC3 5.1 support, its rare that anyone does it. They usually opt for VBR MP3 with an average bitrate of 192k. So now it looks like they can use mp3 still and get the 5.1 Cmon mplayer! make sure you get support fast.. my xbox needs it!
  • Remember MP3? It's back! In Pog form.

  • Fraunhofer reproduces surround sound by adding to MP3 encoding extra information that describes the spatial characteristics of the main audio track.

    Using this extra information helps MP3 players recreate the surround sound effect.


    Pfft. Glorified "expand stereo". We don't need this. A DSP would handle it just fine.. even a lot of built in motherboard sound chipsets have an "expand stereo" slider nowadays. This is pretty much worthless.
  • Missing the point (Score:2, Informative)

    by Egekrusher2K (610429)
    I think most people will miss the point entirely on this matter. MP3's of bands and music recordings, etc., will have absolutely no use for this tech. Where people will see the benefit is when ripping DVD's and encoding AVI files. The best, and smallest, format for AVI audio is MP3. This will enable people to encode MP3s at, say, 160kbps, and also have surround sound. I find this to be quite exciting. I know, I'm a dork.
  • by mikecheng (3359) on Monday March 22, 2004 @01:00PM (#8635408) Homepage Journal
    See ISO13818-3 which describes MPEG2-audio (which is an extention of the original mpeg audio standard - iso 11172)

    ISO13818 describes
    * the Low Sampling Frequency extensions (which describe encoding mpeg audio at 16/22.05/24 kHz). This is already incorporated in most encoders.
    * 3/2-stero+LFE (Section 0.2.3.2 describes the various configurations e.g. 3/2, 3/1, etc)

    For a very brief moment when I had too much time, I worked on getting the multichannel stuff working in tooLame (the layer2 mpeg audio encoder) and the way it works is this:

    1. The encoder works out the overall bitrate for all the channels (X bits)
    2. The encoder assigns some bits (Y) to be used for the backwards compatible 2-channel stereo so that all compliant decoders will work. Y gt X. (The way the 5 channels are crosstalked and cancelled out to get 2 stereo channels is complex. Read the standard if you want more info).
    3. There will then be Z bits (Z=X-Y) left over for the storage of the other channels. (Referred to as "Ancillary data").
    4. The beginning of the mpeg audio frame has a flag set so that compliant decoders know about the extra info.
    5. Old decoders won't grok the flag, and so they'll just read the stereo info, skip over all the extra info and then find the next bit of data they do understand.

    The outcome of all this is that you may have a 512kbps mpeg audio stream which contains 256kbps of the stereo information and then 256kbits of "extra" info that is used to reconstruct the full 3/2 channels of sound.

    There is a problems with this however. Compliant MPEG audio streams have a maximum bitrate as set out in the original MPEG1 standard (11172). For example, the maximum total bitrate of a 44.1kHz mp3 file is 1011 kbps. However, when you do really high bitrate multichannel stuff, you can exceed this limit: in this case, the MPEG2 standard suggests using another file to store the information (referred to as the "extension bitstream").

    Hope this helped someone.
    later
    mike

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