Re: Sound questions

[Ignatios Souvatzis <is%beverly.kleinbus.org@localhost>]

On Tue, Jun 27, 2000 at 02:11:05PM -0400, John Klos wrote:

> Audio on the Amiga, [...]
> 
> However, I would like to learn / know what the relationship is between the
> /dev files. Which /dev talks directly to the sound hardware? How does one
> control the sample rate and volume?

/dev/audioN:    what you see as "audioN" in the kernel startup message.
                default when opened: 8 kHz mono uLaw output.

/dev/soundN:    the same, but the last mode set.

/dev/audioctlN: control device.

N is 0, 1, ...

(Example: On my Amiga I get /dev/audio0 etc. for the custom chip audio device
 and audio1 etc. for the zbus Melody.)

You can use the audioctl program to set speed and modes (see the manual page),
or the audioplay program (in 1.4 and up) to play samples directly (again, see
the manual page). 

Note, as on Amiga it is likely to have more than one audio device, you'll
have to specify which one.

> What is the difference / relationship between /dev/audio(x) and 
> /dev/pcm(x) on FreeBSD? How do I write code that does the same stuff on
> Net and FreeBSD regarding audio?

No idea, sorry.

> Finally, when I set up my next Amiga here, how do I get 44khz output from
> Paula? If I boot my kernel into Multiscan, does 44khz just work?

No. The driver limit is eclockfreq*5/124, the (in)famous 28 kHz magic value.

Using higher video modes to make more possible is actually noted in a TODO
list in the driver comments...

Regards,
        -is