Mail Archives: djgpp/1998/03/04/02:46:22
Gareth writes:
>Has anyone done any hacking of the Allegro Sound Library, as I can't get my
>SB(YAMAHA CLONE :-( ) to play MPEG's or WAV's back at 44khz.
Which of the SB drivers is Allegro trying to use? I suspect that your
card will be emulating the SB-Pro, which is capable of stereo sound at
up to 22k or mono at 44k. By default Allegro will use the stereo mode,
so you will have to explicitly select the mono SB 2.0 driver to get a
higher output frequency.
>Also, the autodetect doesn't detect either my Sound or midi (OPL3-SA)
>properly. For the midi it just decides that it's general midi instead.
I don't understand: what do you mean by "general midi"? Allegro doesn't
have any hardware driver by that name...
I don't know what the -SA bit means, but surely the Adlib OPL3 would be
the correct music driver to use with your card? If this isn't the one
being used, can you give some more details about exactly which driver
Allegro does pick?
In a later post, Gareth also writes:
>I've tried everything you have mentioned already. I decided to hack about
>with the allegro sound library myself and have found what I think might be a
>problem. The DSP chip on my INTEL mothboard returns 301 as the DSP version
>number. I found this using the following code:
>
>printf("SB DSP Version : %x",_sb_read_dsp_version());
>
>The setup utility states that all SB boards (and clones) except SB16 driver
>are 8bit. The setup utility and allegro (yes I know they're the same thing)
>will not let me use the SB16 driver.
So? That all seems quite sensible to me. A DSP version of 0x301 means
that your card is emulating the SB-Pro, so it would be totally incorrect
if Allegro _did_ let you use the SB16 driver with it!
>This must be wrong as my card has a 16bit stero DAC and can run other DOS
>applications in 16bit stero.
But what hardware interface are those programs using? Many SB clone
cards only emulate the 8 bit SB-Pro interface, and then use some other
system (usually either WSS or some custom DAC of their own) for 16 bit
output. Since Allegro doesn't have a driver specifically for your card,
it is limited by how well your hardware can emulate the SB, and from
what you are saying it seems that your card is not SB16 compatible. You
may be in luck if it can emulate the WSS, because a driver for that is
likely to be available in the not-too-distant future, but otherwise you
will probably have to write a new driver for your card or just live with
the limited SB emulation.
--
Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
"Pigs use it for a tambourine" - Frank Zappa
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