Re: Polypaudio for Gnome 2.10, the next steps

["Ronald S. Bultje" <rbultje ronald bitfreak net>]

On Wed, 2004-11-24 at 23:24, Lennart Poettering wrote:
> What is the algorithm you'd expect?

See GStreamer (patch in bugzilla, not in CVS yet). Xine probably does
the same thing. It all depends on channel positions.

For different channel positions, make different mono/stereo sets. E.g.
left/right middle, front mono/stereo, center (or center stereo), rear
1/2, lfe (that's only one). Now for each, grab in/out and mix only over
those (1/2->1/2). So if the in is 5.1 and out is 1.0, drop the lfe, rear
two and center and merge the left/right front into mono. This is not
ideal but it's what most DVD sets will expect. The front speakers
contain the main sound anyway. If you're really fancy, you can also mix
rear/front in a similar manner, but it gets complex then, especially
without testing hardware. 2.0 -> 5.1 will keep the rear speakers silent,
which is fixeable as well but harder since you'll want to pay attention
to userspace rear/front configuration then. First get the first try
correct before you start this. ;).

Ronald

-- 
Ronald S. Bultje <rbultje ronald bitfreak net>