Date: Tue, 16 Oct 2001 17:01:25 -0700 (PDT) From: lyonsm@NETBISTRO.COM To: freebsd-questions@freebsd.org Subject: Compaq sound sampling rate Message-ID: <Pine.BSF.4.21.0110161641420.10590-100000@spatula.dyn.dhs.org>
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Hello,
For the past couple of months I've been trying to track down a problem
with sound playback on my workstation, which is a Compaq Deskpro EN
whose audio hardware probes as
pcm0: <Intel 82801BA (ICH2)> port 0x2400-0x243f,0x2000-0x20ff irq 11 at
device 31.5 on pci0
Kernel config is more-or-less GENERIC with three lines added to the end:
device pcm
device csa
device sbc
OS version is 4.4-STABLE, last cvsupped and rebuilt on Oct 9th.
The problem I am experiencing is that audio playback seems to use the
wrong sampling rate, sounding like 48000 Hz when it thinks it's playing
back at 44100 Hz.
A search of the archives revealed some discussion of cheap motherboard
sound devices that are only capable of playing at 48000 Hz. The suggested
workaround was to use a user-mode mixer process to resample the audio.
Strangely, though, the mixers I have tried (artsd, esound, playwave, and
play) play back at the wrong rate regardless of the rate they are told to
use: when told to play at 48000 Hz they claim they are doing so but the
audio still sounds like a 44.1 kHz stream played at 48 kHz. The same
thing happens when the mixers are told to play at 44.1 kHz (and again
claim to be doing so).
Suspecting the kernel might be lying to the applications about what
sampling rates are in use I modified a copy of esound to ask the kernel
for 44100 Hz but otherwise act as though it had asked for 48000 Hz. This
seems to have worked around the problem for now, but leaves me unsatisfied
-- surely this shouldn't be necessary.
I'm pretty much stumped at this point. Has anyone else seen this? Is
there some other knob in the kernel config I should have adjusted?
Thanks in advance for any clues!
-m
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