On Fri, 10 Apr 1998, Chris Gilbert wrote:

> In message <Pine.NEB.3.96.980410073543.12972E-100000@riscbsd5.client.nc.com> you wrote:
> 
> > The audio drivers need overhaulling, anyone want to volenteer ? ;-)))
> 
> I've got a working driver, that works fine for 16 bit sound, but doesn't
> work in 8bit mode, I think there's some additional hardware there that I
> don't know about.
> 
> The 16 bit stuff seems to work for 8bit mono mulaw and 16bit stereo
> linear in it's different formats. I've not got a beep device working at
> present, the standard beep device clashes on the interrupt, my plan is
> to get the beep into the vidcaudio driver, I've a few ideas but the
> vidcaudio code is a mess and I lack samples to test the system, ie the
> one I've got is converted by lots of conversion things, any suggestions
> for where to find some would be appreciated.
> 
> Another problem is that the 8bit mulaw is emulated using the auconv
> routines, however these make the overall sample size larger and this
> size change is picked up by the high level audio driver, so I hope to be
> able to use the 8bit mode on the vidc to do 8 bit mulaw, however I've
> no idea what is done after the sound leaves the vidc as I get no
> output...
> 
On systems with 16bit sound it is not possible to get 8bit sound out of
the system as the 8bit audio path is overidden on machines with 16bit
upgrades and probably doesn't even exist on the machines that came with
16bit sound by default. As I understand the VIDC20 sound system you are
doing the right thing by converting the samples from 8 bit to 16 bit. 

I suspect the vidcaudio driver will need to work the opposite way round on
a system with only 8bit sound (i.e convert 16bit samples to 8bit). 

I have the capability of switching between 8 and 16bit audio very simply
so if you want me to give things a try let me know.

Mike