Seeing how many posts there are on sound problems, I thought I should add a seperate thread. Please contribute.

Here are the steps I have done so far:

1. Installed from knoppmyth...runs perfectly but no sound. R4V5 is the software I am using.

hardware: Dell Pentium 2.4 Ghz, 120GB, happauge WinTV Go and built in sound card from Dell. ( I dont even know which one this is)

I connected the speakers direct to TV ( pretty dumb huh) and this caused audio to be out of sync. The reason is even the Live TV is recorded and what you see as Live TV is behind by a few seconds. secondly, if you directly connect the speakers, there is no audio input to record audio on the TV programs...and finally how would you play CD/DVD and get sound?

So now I did the right thing: Connect the Line out from TV card into Line in on sound card through a simple audio jack that came with the TV card. Then the speaker is connected to sound card. Now comes the real issue. Still no sound on my TV or recording. Did not check whether audio CDs produce sound etc.

2. Started research on why sound does not work: figured from research there are at least 2 options:
2a: Sound Card is not supported: Solution: Try a new sound card.
Hope to have this thread compile a list of known to work sound cards.

Review this link: http://www.alsa-project.org/alsa-doc/index.php

I checked for Creative cards only. I still cannot understand whether my card is supported by mythtv, if alsa supports it or not....but I will try posting some info.

If you are like me, the sound card came with the Dell Box and i dont know what card this is.

Maybe you can try this:

lspci -v | less:

(11/24: I did this myself and found out that my Dell box has an Intel audio card...and in the same line it says unrecognized something or the other...but the good news is I did get the audio to work and let this not be a deterrent.)

This should give a list of all PCI controllers??. Look for the multimedia controller and check that in the list of cards supported on the link above: (http://www.alsa-project.org/alsa-doc/index.php)

Assuming the sound card is supported go to step 2b

2b: see if input is setup ok: Go to step3

3. Alsamixer for noobies:

Ok...I had to reasearch how to "run" alsamixer. So even if this sounds dumb, just thought it will help a fellow noobie. So I researched Google and found this:

At the command prompt ( dont know whether you need to be root): You can get to the command prompt by hitting ESC untill you quit mythtv and then left click your mouse and hit Xterm.

$ alsamixer

This will bring up like a nice graphical display and you can drive up or down the volume using arrow buttons. Scroll to the right...there are many places to set or reset audio levels.

Apparantly the default install mutes "Line" in here, which have to be "Un"muted before sound works.

Second if anything is muted, it will say MM at the top of the bar or maybe OFF. Just press m and it will be unmuted. I think Line in has to be unmuted.

I unmuted Line In on my system and it still did not work. Then I started unmuting one by one and narrowed it down that only when Line In and headphone are both unmuted and volume set to about 70 audio comes on.

However this or something is causing an echo effect. I get the realtime audio audible very feebly and followed up with mythtv audio that is in sync with the video. I dont know whether something in the alsomixer that should be left unmuted is causing this?

Can somebody help and say what exactly has to be unmuted??

Here is what I found ina post today:

I set the master volumn to about 70. I set the PCM volumn to about 0. Set line-in to about 70, selected capture with the space bar, and set mute. I have to try this out to see if the echo effect goes off.

Even if you have quit mythtv,( thats how you are the command prompt I guess) as long as the audio works, it will be immediately audible. I think MAYBE, the reason is the backend and front end is on the same box and hence even if I have closed mythfrontend, the backend is still on etc. If you dont hear the audio, no sweat. Go to step 4.

Once you have "un" muted whatever needs to be unmuted, it needs to be saved:

Use this command to store it:

$ /usr/sbin/alsactl store

If that does not work, maybe you need to find out where the path to alsactl is

I would use a simple unix find

$ find / -name alsactl


and then type the entire path to alsactl as:

$ /whateverpath/whateverpath/alsactl store

Go to step4

However when I did this myself, it turns out knoppmyth does not install alsactl...or when I do find, I get nothing and I cant use the command. So I am still struck with having to manually start alsamixer everytime.

Can somebody help me on how to store this, by getting alsactl ? Should I do a apt-get install alsa-utils? I dont want to break anything right now.

Ok did some more search on the postings and found this:

apt-get update
apt-get install alsa-base
(it will error)
you then need to do a dkpg -i --force-overwrite the name of the file it errors on. ( i dont remember the exact command its in the forum.).

And I think this will also help to know, whether its applicable to R4 V5 I dont know:

the version of alsa on ver R4V4.1 is older, and something doesnt work quite right with saving settings. So IMHO the best solution is to say screw it, and get the newer version of alsa (hence my directions posted above). When you install the newer version of alsa, saving settings works in aumix and alsamixer. even on reboot.

4. This is shamelessly copied from: http://knoppmythwiki.homelinux.org/inde ... AudioHowTo

Start up MythTV frontend again. Go to Settings->General and change Audio from "/dev/dsp" to "ALSA:Analog" just to test. Start a recording or live TV. You should hear audio via the analog outs as usual. Then return to the general settings and change Audio to "ALSA:Digital" to activate digital output. Return to a recording or live TV. You should hear audio via your digital out. (You may need to use the strings ALSA:analog and ALSA:digital, they seem to be case-sensitive on my system. --liv2cod)

This may have changed with release KnoppMyth R4V5. The setting "/dev/adsp" seems to work now for Settings->General. There may be further developments so stay tuned...

I tried this, and for ALSA:Analog, mythtv warned me that there is no audio source. So I simply changed it to dsp0 instead of dsp and it worked. I dont understand the reason why dsp0 would work instead of dsp...but thats for another day.


5. Onboard sound: Need to research this: apparently if you have multiple tuners this is the best option. Seems obvious considering there is only one Line In jack/port on the sound card.

6. So far this is the status:

a. Sound works, but there is an echo effect with the realtime voice audible very feebly a few seconds before the mythtv audio which is in sync with video

b. I do not have alsactl so I dont know how to store the settings. I wantto check to see if I can do an apt-get install alsactl which could fix this issue

Please help.

This is what the FAQ and the wiki are for...

Also researched several sound related posts and here are my notes in a notepad.

I am not sure whether all this applies to the latest version or not, but here is everything. Note this is not step 4. These are just random notes and even the commands are not necesssarily in sequence.

Can the more knowledgeable reorganize this:

Begin research notes:

you may want to try running 'alsamixer' and checking to make sure that the volume on your line in is not set to zero, and is set to capture (space toggles). I'm assuming your capture audio is going to line in. The volume defaults to zero on install.

v4lctl -c /dev/video setattr mute off

I believe recompiling ivtv is not necessary if you are using R4V5. ( I may be wrong). But if if you dont have R4V5 running here is the stuff:

cd /usr/src
# The ivtv compile needs the src files.
tar xvfj linux-2.4.25-chw.tar.bz2

cd /usr/local/lib/ivtv/driver
make clean
# I suppose I could have used 'make install' but I was testing
# and didn't want to add to my problems.
make

cp msp3400.o /lib/modules/2.4.25-chw/kernel/drivers/media/video/
# And answer yes to overwrite the existing file.

# Then, if you don't like extra files just lying around:
cd /usr/src
rm -rfd linux-2.4.25-chw
# to delete the source files previously extracted.





cat /var/log/messages | less
cat /var/log/syslog | less
cat /etc/modules.conf | less

Lspci -v | less

cat grep /proc/pci
grep -rs sound-slot /etc*


update alsa-base

lspci

test_ioctl -a





PostPosted: Tue Sep 21, 2004 5:48 pm Post subject: Reply with quote
"alsamixer" is the answer. "alsactl store" is also necessary. I then modified the /etc/init.d/Sound script. I commented out the line that set the volumn. I substituted it with "alsactl restore". KnoppMyth did not instal the alsa-util package. I downloaded the source, extracted it, ran "configure", and run "make". I then copied alsactl to the /usr/bin directory.

I set the master volumn to about 70. I set the PCM volumn to about 0. Set line-in to about 70, selected capture with the space bar, and set mute.

amixer is also part of the alsa-util package. It can be used to set up the sound card as well. But I decided that alsactl was easier.
Back to top
View user's profile Send private message
NewtonRob



PostPosted: Tue Sep 21, 2004 5:50 pm Post subject: Reply with quote
There is a mistake on the second paragraph. I set the PCM volumn to about 70 not 0. Sorry.

etc/modutils/alsa-0.9-knoppix

I finally figured out that the file /etc/init.d/Sound was loading some settings by default INSTEAD of from /etc/aumixrc. To fix this, I simply changed the following line in Sound
ARGS="-v 70 -l 0 -l R -w 70 -m 0"
to read
ARGS="-L"