[sdlsound] alt_audio_convert

[Frank Ranostaj]

> 
> Yes, it is intended to do so. I though, it was  more or less working.
> The allocation interface in playsound should take a additional buffer
> length into account for the settling time of the filter.
> The conversion e.g. 44.1 <-> 48.0 is approximated by 44.0 <-> 48.0.
> The use of Splines can be superior to the windowed sin(x)/x filter
> used in the alt-converter.

http://aulos.calarts.edu/pipermail/test/1997-December/000782.html

It seems to be the other way round.
Perhaps it would be useful to have both opportunities: 
- for low cpu-usage splines
- for maximum quality sinc filter? 

    Frank Ranostaj