[vorbis] Multichannel files

[Wilson]

There are two ways to decode multi-channel audio. In hardware, or in
software.
Hardware: A receiver or processor takes a Dolby Digital (for example) stream
and converts it into something your amps/speakers are interested in.
Software: Your PC decodes a 5.1 audio stream into six discrete audio streams
and passes them to analog output.

Sound cards that can handle what is described in the second case are fairly
rare. The Hercules Game Theatre XP, the M-Audio Delta Theatre ($$$), etc.
Most people don't have them. Doing real 5.1 output from the PC without a
receiver that locks you into Dolby Digital is either expensive (full pre/pro
combo) or rare (analog 5.1 multimedia speakers with LFE management. Hard to
come by.)
To play a multi-channel Ogg file through a receiver, the receiver would have
to directly support Ogg, and the sound card drivers would have to support
pushing the Ogg through Toslink or S/PDIF. An alternative is to transcode
the Ogg output on the fly into AC-3 for transport, but then we're not
patent-free anymore.

Either there's something I'm missing, or I don't see much of a use for 5.1
Oggs.

"In the grim future of Hello Kitty there is only war..."
http://supremetyrant.com/HK40K.jpg

----- Original Message -----
From: "Mercier, Dave" <dmercier at ea.com>
To: <vorbis at xiph.org>
Sent: Wednesday, November 14, 2001 3:56 PM
Subject: RE: [vorbis] Multichannel files

> I think multi-channel is one area where Ogg could really find a niche for
> itself. The reasons:
>
> 1) 5.1 Music is becoming more popular. There are DTS 5.1 audio discs in
use
> now. There isn't really a way to stick these into a convenient playback
form
> that I'm aware of though.
>
> 2) I'm not aware of a widely available MP3 encoder that supports a 5.1
> configuration. There are extensions to the MP3 format that allow 5.1, but
> I've never seen them used anywhere for the average person (I think
European
> DVD's use 5.1 MP3 or something perhaps).
>
> 3) It seems formats like Dolby Digital and DTS are not being pushed onto
> consumers very hard. Show me where I can get a DD or DTS encoder to encode
> my files. I'm not so sure you will see this pushed on to people either.
>
> 4) I really have no idea if formats like WMA and others support 5.1. But I
> can't think of any of these as being too friendly to the average person
this
> way either.
>
> 5) It's really easy to add 5.1 support to an Ogg encoder, and it will be
> available widely.
>
> 6) On the PC writing or extending a player to handle 5.1 audio would be
> pretty easy, if a sound card supports it (e.g. something like an SB Live
> 5.1).
>
> 7) There was talk earlier of why a PS1/PS2 could or couldn't handle Vorbis
> playback as an entertainment device. I've been thinking about this a lot
> lately, and I think this would be excellent. A PS2 player could be written
> that plays Vorbis files. This player could also do real-time DTS or Dolby
> Digital encoding. So if a user plays a 5.1 format Vorbis file, the PS2
> switches into DTS output mode, decodes the Vorbis into 5.1, and then
> re-encodes it into DTS 5.1 and sends it out the optical. The re-encoding
may
> introduce a bit of artifact, but not likely if done right. You then get
the
> benefit of a digital connection to your 5.1 setup. I know I use my PS2 a
lot
> to play CD's, just because it has a digital connection. But Sony's CD
player
> is a horrible thing and I hate changing CD's every 45 minutes. I'd really
> like to copy 15 or 20 albums onto a CD and let it rip through a good
Vorbis
> player (of course it could play MP3's, etc., as well). I'd really like to
> start a project like this myself, but I fear two problems 1) Sony would
not
> approve such a player, since it allows the possibility of playing pirated
> music (hey Sony is a big music company), and 2) I'm not sure the PS2's
laser
> can read CD-RW discs. I think it can read CD-R's but I'm personally not a
> big fan of only burning something once. Other than those logistical issues
I
> think the technology is pretty simple. I know I'd be willing to spend $30
on
> some PS2 player software that would transform my PS2 into a wicked high
> quality audio player.
>
> Thanks,
> Dave.
>
> -----Original Message-----
> From: Andreas Karlsson [mailto:a.karlsson at bredband.net]
> Sent: Wednesday, November 14, 2001 12:36 PM
> To: vorbis at xiph.org
> Subject: RE: [vorbis] Multichannel files
>
>
> Hi Myles,
>
> Thank you for your reply. I´m indeed very serious about trying to make
> music in surround.
> I find it a very intresting way to extend the expression of music. As
every
> one knows,
> stereo is made to make the soundscape whider and more expressive, surround
> will add
> new ways to place the listner in the center and carry him/her away.
> I´ve now read the threads and I´m not trying to make any technical
> suggestions. I´m just
> experssing my desire to find new fronteirs.
>
> Regards,
> Andreas Karlsson
> http://www.ft2.net
>
> At 15:03 2001-11-14 -0500, you wrote:
> >Hello Andreas,
> >
> >There was a few threads some months ago on multi-channel oggs and various
> >surround formats.  I suggest you search the mailing list archives for the
> >word 'ambisonics'  You should find relevant threads in that era.
> >
> >I have some issues with current surround sound recordings as they lack
> phase
> >and position information in the sound matrix.  If you are serious about
> >proper surround recordings It will take some effort on the part of the
> >vorbis project and current players to keep and reproduce proper
> >phase/location data.
> >
> >Myles
> >
> >-----Original Message-----
> >From: Andreas Karlsson [mailto:a.karlsson at bredband.net]
> >Sent: Wednesday, November 14, 2001 13:58
> >To: vorbis at xiph.org
> >Subject: [vorbis] Multichannel files
> >
> >
> >Hi,
> >
> >As I´ve understood things, the Ogg Vorbis format supports more that two
> >channels (stereo). Is there any tools to encode x sourcefiles into one
.ogg
> >file?
>
>
>

--- >8 ----
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