[vorbis-dev] How to copy encoded channels?

Rob Fletcher rpf1 at york.ac.uk
Mon Jan 22 01:52:03 PST 2001


Having worked on a 4 channel encode/decode system, which works just
fine (using 4 channel audio on SGI systems). I now would like to think
a little further about how 'n' channel encodes may be used for 
network collaboration in music.

Let's imagine a 16 channel codec, and let's say we are working in a
simple stereo in/out environment (i.e. like most consumer devices
out there). Musician (a) records some music and makes a stereo
mix. He then encodes this as a stereo ogg file. He sends it to 
musican (b) who then records his contribution.

It would be nice if we could then merge the two and so on.

Ideally of course, with 255 tracks available, then we could see
this as a container format for multitrack music. Wouldn't it be
nice to have an application where each (mono) track decoded,
panned to L+R and has a level set (easy in the decoder).

Of course, we cannot render to raw data and re-encode as this is
bound to introduce (more) artefacts.

SO, does anyone have any thoughts about how to copy an existing
encoded track into a new file, and at the same time sync in

Of course, the easiest thing is to be able to play back the
already encoded tracks whilst recording the new stuff, but there
is still the sync issue here.

If we could think about this now, at a relatively early stage
we could be looking at an interesting method of music
distribution. (OK, I know all the args about the producer etc
having already put in the effort for the mix, and that's how it
should stay - we have the same args with multiple viewpoints
with digital TV. If the mix is fixed, it can be fixed).

Hope you see what I am thinking about - I expect those who do
any multitrack recording, either with hard devices (n-track
tape, DAT, disk) or soft, with the likes of VST etc, will 
hopefully see where I am going.

Any plans afoot for using the multitrack formats (other than
the various surround sound, ambisonic stuff) ???



| Dr R P Fletcher    (Rob)   | Email     R.Fletcher at york.ac.uk    |
| Graphics Coordinator       | Phone     +44 (0)1904 433816       |
| Computing Service          | Frontdesk +44 (0)1904 433800       |
| University of York         | Fax       +44 (0)1904 433740       |
| YORK YO10 5DD, UK          | ICQ UIN   4019164                  |
| URL: www-users.york.ac.uk/~rpf1/  Camera: /~rpf1/robcam.html    |

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