dsound: change mix rate of primary buffer

[Andrew Eikum]

On Tue, Dec 18, 2012 at 08:08:03PM +0100, sebastien chev wrote:
> Thank you for the tips. I will look at these.
> 

I guess you're probably also thinking about the mix buffer in dsound
itself. That does always mix to float, and there isn't a way to change
it right now.

What are you planning to use this for? We could support different mix
buffer formats, but I'm not sure this use case is worth the effort.

Andrew