[mythtv] Yipee, almost there but audio whine

[Tony Clark]

This really sounds like audio feedback to me due to something wrong with your 
mixer settings.  Make sure you have just 2 sources set to record.  Line in 
and capture.  Mute line in and turn wave(PCM?) and and capture up.  Turn all 
other level adjustments down to zero.  You might have to have wave, record 
enabled as well but no more than that.  The audio level responds quite slowly 
after you adjust a level so be in a hurry.

tony


On Friday 03 January 2003 06.56, Bryce C wrote:
> Update: I've tried a CMI8738 based card and I don't get the same whine I
> did.  Now, I get an even higher pitched (worse) whistle when listening
> to live tv.  I haven't tried recording yet but I'm not optimistic.
>
> On Thu, 2003-01-02 at 20:41, Chris Liscio wrote:
> > 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

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