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Hello -
I am having some sound quality problems. Any
ideas of things to try would really be appreciated. I have links to some
audio file samples below for the good and bad cases I have
recreated.
System Background:
- Commell LV-670 (per documentation audio is Intel
ICH4 with Realtek ALC650 AC97)
- CentOS4, updated kernel to 2.6.17
- ALSA version 1.0.11rc4
- I have played with the alsamixer settings without
progress. I even have tried PCM, line, and all the other
settings down below 10%.
- lspci shows: 'Multimedia audio controller: Intel
Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev
02)
Problem:
I am attempting to capture video and audio via the
Real Networks realproducer v10. According to Real, the OSS compatibility
APIs are used, and ALSA may work but is not supported. When I use the
above mentioned ALSA driver, the audio has a horrible sound when played
back in RealPlayer. While capturing, the PCM output to the speakers sounds
great, as does playing wav files. I can successfully use arecord and aplay
as well.
- Here is a link to the "bad sounding file" - http://www.thehurffs.com/bad_alsa.rm
The problem only seems to be when audio is captured
through the OSS interface (assuming I have the terms correct based upon Real's
statements about OSS and ALSA support). I am not very smart on the
ALSA/OSS compatibility...
Additionally, I downloaded the commercial OSS
driver from http://www.opensound.com/. This
driver works flawlessly through realproducer, as well as straight arecord,
etc. While this driver is an option, I would much rather not have to
purchase the driver and deal with future support. I'd like to just use the
standard distro ALSA drivers. Since the OSS driver works, it leads me to believe it is simply an issue with my ALSA driver
config, maybe a modprobe parameter, sampling rate, alsamixer setting, or
something of that sort. I looked at the intel module parameters and tried
the rate one, to no avail.
- Here is a link to the "good sounding file" - http://www.thehurffs.com/good_oss.rm
Are there known issues with this chip? Or do
you think it is an issue of RealProducer/OSS/and the chip all together? I
have seen a lot of references to the nForce clock rate issues referring to 44.1
KHz vs 48 KHz, resampling issues, etc. But the suggestions have not really
made a difference. Do the files I linked sound like a sampling issue, or
something else?
Thanks SO much in advance!
Burt
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