[mythtv] Yipee, almost there but audio whine

[Chris Liscio]

Well, I also have a poor quality sound chip (and not just in the
full-duplex category), but I think that spending the time to get btaudio
working might pay off.

It all depends on your level of patience, I guess.  For me, I have a
mixture of Alsa (emulating OSS for my snd-via82xx module) and OSS
(running via btaudio natively).  When you run 'sox -t ossdsp /dev/dsp1
test.wav' (where /dev/dsp1 is your btaudio device) you should see a
message that says it's unable to set the sampling rate and it defaults
to 32000.  That's when you know you're hitting the right device.

So to go back to what you said, you don't have to kill alsa.  You just
have to augment it with the new stuff.  It may be painful but possibly
worth the learning experience in the end.

Hope this helps.  I'm all about making the cheapest configuration work
best... :)  Oh yeah, it doesn't help that there aren't very many good
half-height PCI audio cards, either.  ;)

Cheers,
Chris

-----Original Message-----
From: mythtv-dev-admin@snowman.net [mailto:mythtv-dev-admin@snowman.net]
On Behalf Of Bryce C
Sent: Thursday, January 02, 2003 10:20 PM
To: mythtv-dev@snowman.net
Subject: RE: [mythtv] Yipee, almost there but audio whine


When I WAS TRYING to use btaudio, it created /dev/sound/dsp[1-4] and
/dev/sound/mixer[1-2] because I have two cards that have separate
purposes (one only does composite) and and are accessed separately. 
dsp[3-4] are the only one's I'm concerned with but I tried a sox on
dsp[1-2] too and here's what I found. The digital ones said nothing, no
"Recording at a rate of 8000 of type WAVE" or whatever it was.  It just
sat their.  Also, yes, ,I am using alsa because oss didn't seem to work
before and it took a lot of work to get alsa installed so i'm not about
to try again.  The arecord was used after I reverted to ALSA so yes, it
was using ALSA's line-in. I think I've found the problem in a poor
quality implementation of full-duplex capability on my sound chip so i'm
going to try another one.

On Thu, 2003-01-02 at 19:25, Chris Liscio wrote:
> That is certainly strange.  For me, doing what you've done did not 
> yield good results at all.
> 
> I know for one thing that I used sox to do the recording from the oss 
> device /dev/dsp1 manually rather than using arecord (to guarantee it 
> was using the right input device).  It *is* possible that when you're 
> doing arecord >test you are still using the Auxillary input on your 
> sound chip.  Someone feel free to correct my highly uninformed 
> hypothesis though...
> 
> Also, you must make sure that you are setting mythTV to use the bttv 
> device for recording, and the alsa device for playback.
> 
> That's about as much as I can offer right now.  YMMV.
> 
> Cheers,
> Chris
> 
> -----Original Message-----
> From: mythtv-dev-admin@snowman.net 
> [mailto:mythtv-dev-admin@snowman.net]
> On Behalf Of Bryce C
> Sent: Thursday, January 02, 2003 8:30 PM
> To: mythtv-dev@snowman.net
> Subject: RE: [mythtv] Yipee, almost there but audio whine
> 
> 
> It still doesn't work.  On a considerably more interesting note, I did

> an "arecord >test" and then "aplay test" and it was flawless.
> 
> On Thu, 2003-01-02 at 18:10, Bryce C wrote:
> > I had tried the btaudio driver initially but I could never get it to
> > work but now that I know my setup DOES work basically, I think I'll 
> > try it again.  Just to verify, you're saying that you're using the 
> > digital dsp device at 32000 and it works for live and recording?
> > 
> > On Thu, 2003-01-02 at 17:44, Chris Liscio wrote:
> > > 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
-- 
Bryce C <Plug@BryceCo.Net>
CoBryce Communications