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SubjectRe: RFC: big ac97_codec audio update
Rui Sousa wrote:
> On Thu, 19 Oct 2000, Jeff Garzik wrote:
> > We need the dynamic bit resolution detection.

> Isn't this producing noise/pops? (since you maximize the volume).

During audio init I hear pops, but then again I heard pops during audio
init before these changes too :)


> > Judging from comments already received, it looks like we need to do
> > logarithmic instead of linear scaling for the OSS mixer values (0 -
> > 100).

> ? The scale (AC97 and OSS) is linear in dB units which is,I believe, how
> we perceive sound.

With maestro, trident, and via at least, the volume has to be at 80% or
so before any sound can be heard.


> Could you include this macro (it gives you perfect accuracy and
> prevents mistakes):
>
> /* scales the range a:b to min:max rounding to the nearest integer */
> #define scale_range(val, a, b, min, max) \
> ((((val) - a) * ((max) - (min)) + (min) * (b - a)) *
> 1000 + (b - a) * 500) / (1000 * (b - a))

> I will provide a patch if you agree.

Please do...


> Everything else looks ok but I still need to test it.

Thanks!

Jeff


--
Jeff Garzik | The difference between laziness and
Building 1024 | prioritization is the end result.
MandrakeSoft |
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