Re: XFree 3.3.6 SOUND problem (?)
Hello,
On 26-Mar-00, you wrote:
BR> On Sun, Mar 26, 2000 at 12:28:08PM +0000, Esdras Beleza de Noronha
BR> wrote:
BR>> I'm having a very, very strange problem with XFree 3.3.6.
BR>>
BR>> I have a SiS 6326 (it uses the XF86_SVGA server) and a CMI
BR>> 8330/SB16 soundcard, and they're configured. When I run X using the
BR>> 16 bpp resolution, my sound is very, very bad, with creaks. But
BR>> when I run it using 8 bpp, the sound is very good.
BR>>
BR>> I tried ask this to half Linux community, but nobody gave me a
BR>> solution. Can you help me?
BR>
BR> Perhaps someone else on debian-user could share their experiences
BR> with this person?
BR>
BR> The only thing I can think of that is that whatever you're doing in
BR> 16bpp puts more demands on the host processor than 8bpp mode. This
BR> is definitely going to be true in situations where the host CPU does
BR> a lot of "blitting" to the framebuffer "by hand". This might happen
BR> in 2D games, for instance, where there are a lot of refresh events.
BR>
BR> Other than that, I really have no idea. There is currently no
BR> defined standard for interfacing a sound server of any sort with the
BR> X server. (There probably should be, but life is short and art is
BR> long.)
Running at 16bpp can require more cpu than 8bpp because the palette can
be so much larger. However, if your display only requires 256 colours
it shouldn't make much difference because the 'used' palette would be
the same size. Does the content that you're displaying make any
difference to the sound? i.e. few colours? animated graphics or still
images? Does changing the x-y resolution make any difference?
Try running a system monitor to check your resource (cpu/mem/etc.) usage
at 8bpp and 16bpp and compare.
It's my understanding that colours are generally computed at 24bpp -
3x8bpp for R, G & B (32 bit displays are generally 24bpp + 8bpp alpha
channel, but 36bpp (3x12bpp) scanners aren't uncommon), and are then
mapped onto the available palette if the display isn't running at
24bpp. It might actually be better at 24bpp if you've got a reasonably
new video card because it wouldn't have to do a look-up from the 16bpp
palette.
Bye,
LeeE
--
http://www.spatial.freeserve.co.uk
...or something.
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