[linux-audio-user] Common linux audio layer

[Lee Revell]

On Sun, 2005-01-16 at 08:41 -0800, Mark Knecht wrote:
>    The ONLY REAL-TIME solution to this problem is for the two machines
> to be synced somehow so that they run at the exact same frequency.
> Some high-end consumer audio equipment is including expensive hardware
> for doing this via 1394 interfaces, as do some high-end sound cards
> via Word Clock, ADAT, spdif or other interfaces.

Microsoft claims that the audio system in Longhorn solves this problem.
It looks like their solution requires driver & hardware support for
mmaping (aka very fast access from userspace) the wall clock and
position registers, then they correct for the drift.  Of course this
certainly involves resampling everything in software.

Anyway it's an interesting read.

http://download.microsoft.com/download/5/b/5/5b5bec17-ea71-4653-9539-204a672f11cf/WaveRTport.doc

Lee