[vorbis] Multichannel files

[Mark Hetherington]

I think that surround would be great. 

Now I'm pretty sure the sound card+ drivers should be encoding the surround 
signal into one usable by the spaekers, so it shouldn't be a patent issue for 
ogg. In the same way as you do surround in a game, you should be able to 
position the audio streams when outputting them, without having to support 
AC-3 or anything other than the standard sound interfaces.

I don't really know the technical aspects of writing software to output in 
surround but I know there are some Alsa layers doing surround.

On Thu, 15 Nov 2001 08:05, you wrote:
> 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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