When trying to watch LiveTV (or record) I get video fine, but not audio.

I've tried the troubleshooting guides tips of using xawtv and "aplay /dev/dsp". I managed to get the echoing/delayed audio, but still no tv audio in MythTV. In the setup screens audio in and out is set to /dev/dsp.

I can play a CD in myth ok. I even tried ripping it to disk and playing the resulting ogg files, which also worked.

Can anyone please help me solve this problem?


Sometimes I think I should have just stuck with the crappy myHTPC + custom program + VirtualVCR setup I had working under windows about six months ago. That was before I decided to be a bit more ambitious.

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Paul Turpie
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You're not providing much information. What tuner do you have? Have you searched the forum? have you taken a look at the MythTV docs?

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cesman

When the source is open, the possibilities are endless!

Sorry about the lack of details, I was just thinking about it this morning while I walked my dog and realised that I hadn't given any hardware info.

The tuner is a LifeView FlyVideo 3000.
I'm not sure of the motherboard, but the processor is AMD 2400+XP, and heaps of RAM.

It isn't a PVR so I assume the other forum tips of recompiling ivtv don't apply.
The tuners audio out is plugged into the line-in on the soundcard.

After reading the MythTV troubleshooting docs and searching the forum here I have installed aplay and can hear the audio slightly delayed, while watching a muted xawtv.

So I assume I have alsamixer setup correctly because I can hear the audio from "aplay /dev/dsp" while watching a muted xawtv.
MythTV seem to be able to output audio because it can play sound from CDs or Ogg files, but for some reason it can't input it with my current setup.

If there is more information you need please let me know.

Thanks
Paul T.

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Paul Turpie
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well just a couple of things and you have probably already looked at this, but you didn't mention it. have you made sure that line in is set to be the capture device? if so you might want to try some of the other possible capture devices. I have seen some linux sound drivers do wierd things mixing up inputs and stuff.

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Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

Is alsamixer the right place to check if "line-in" is set to be the capture device?

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Paul Turpie
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That or aumix...

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cesman

When the source is open, the possibilities are endless!

Sorry if I'm asking a bunch of stupid questions here, but I'm currently at work and can't check these things myself.

If I mute the audio in xawtv but can hear the audio via "aplay /dev/dsp", doesn't that mean the capture device is set properly?

When I get home I'll try the aplay thing with every possible capture device to see if any others work.

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Paul Turpie
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Over the weekend I tried a few more things.

First I ran xawtv and got sound with an unmuted line-in, then I muted line-in and sound disappeared. Then with xawtv still running, I ran aplay "/dev/dsp" with line-in as the capture device, and sound was working. I then used alsamixer to try every device as the capture device, nothing but line-in produced sound.

Then with line-in muted and set as the capture device I ran MythTV and got the usual video but no audio except for a low volume static. Then I used alsamixer again to try every capture device but still nothing worked.

Is it possible there is a glitch in my VIA motherboards on-board sound?
Or could MythTV be trying to grab the audio directly from the saa7134 based FlyVideo 3000 tuner card?

Any help would be greatly appreciated.
(I seem so close but still so far )

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Paul Turpie
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never heard of the tuner card. does it happen to use the ivtv drivers? if so look for the recomple ivtv thread.

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Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

No, it use the saa7134 module.

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cesman

When the source is open, the possibilities are endless!

PROBLEM SOLVED!

After doing some more googling I stumbled upon the solution.
Apparently the saa7134 v4l driver is initially muted on boot up.
Xawtv works because it mutes and then unmutes the driver upon starting, unfortunately MythTV doesn't know to do this so it gets no audio.
Because the audio is muted in the tuner card it isn't even coming out its audio-out socket.

Some people on the net had been modifying the driver source, but the same result can be acheived with the v4lctl program.
If I run "v4lctl -c /dev/video setattr mute off" after booting the pc, the tuner card will work fine in MythTV.

My only question now is how do I get the command to run automatically when the pc boots? Under Redhat I would have used rc.local, but how do I do it under Debian/KnoppMyth.

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Paul Turpie
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Thanks for answering your own question, I ran into the same situation and this post saved me some hassle.
I suppose you're not expecting an answer to your last question anymore, but like this post helped me, others may find this addition useful.
There are many ways to make v4lctl run at boottime. I added this line to /etc/modutils/actions:



and ran update-modules. This way the command is tied to the loading of the module.

Thats probably a smart place to run the command. I put it in /etc/init.d/bootmisc.sh.

Thanks for your input,
Paul

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Paul Turpie
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Great example of how the forum can work!
Problem was posted 6 months ago.
User problem was solved, solution was posted.
6 Months later, user searchs and find solutions that works!
Great work gents!

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cesman

When the source is open, the possibilities are endless!

I was having a problem similar to yours.

My audio was coming across but it was making a loud screetching bell ring noise.

I have a nforce 2 board with ac97 built in audio and a leadtek winfast 2000 xp card. With a cable from audio out to line in.

I had used the mixer program to mute line in and set capture to max.