[mythtv] Yipee, almost there but audio whine

[Chris Liscio]

I actually just got my new mainboard which was equipped with a VIA8233A
SouthBridge and a Realtek ALC101 audio codec chip.

When I first started MythTV with this chipset it was horrible-sounding.
I couldn't figure out what exactly was wrong.  I tried xawtv with the
Aux line enabled and it sounded just fine.  I am guessing it had to do
with the fact that it was just analog in to analog out straight-through.

So I used arecord and aplay to verify that recording internally to the
chipset produced horrid results (crackly, fuzzy audio that sounded as if
it was going through a ring modulation sound effect processor...).

No tweaking at all would change this behavior (other than keeping the TV
*very* quiet) and I was stumped for all of 2 hours.  I remembered that I
could just use the btaudio module for recording, and keep using my
(perfectly fine for PCM) ALC101 for playback.

After mucking around and making sure all the OSS stuff worked properly
(now I have /dev/dsp0, dsp1, and dsp2) and was set up properly in mythTV
(in cvs, you'll have to go into the database and change the input audio
device...in older versions this just involves a text file edit).  I also
stumbled on the fact that you could only record at a sampling rate of
32000 briefly.

Starting mythTV up again (and with my fingers and toes crossed) I was
pleased to hear everything working correctly.  It now sounds as
fantastic as it ever did.

Hope this solves your problem.  The ALC101 is a *very* cheap audio
device and they most likely use crappy ADCs and DACs and mixers
internally to do all the mixing and recording.

On another note, the GrooveBox appears to be a go... :)

Cheers,
Chris

-----Original Message-----
From: mythtv-dev-admin@snowman.net [mailto:mythtv-dev-admin@snowman.net]
On Behalf Of Tony Clark
Sent: Thursday, January 02, 2003 5:15 PM
To: mythtv-dev@snowman.net
Subject: Re: [mythtv] Yipee, almost there but audio whine


On Thursday 02 January 2003 22.58, Bryce C wrote:
> Just the high pitched whine and sometimes the voices are a bit 
> "warblely".

You may have the AC97 level turned up, I think I got some sort of
feedback 
with my SBlive card when I had the AC97 level up.  I guess your using
alsa?

tony



-- 
Contract ASIC and FPGA design.
Telephone
+46 702 894 667

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