bttv audio?

bttv audio?

Post by Andrew Schulma » Thu, 18 Nov 2004 01:21:59



I have a cheapo Bt878 TV tuner card-- an AITech WaveWatcher TV-PCI.  It
cost $10 and it works, so I'm happy.  That is, the video works, but so
far the audio doesn't.

I know (or at least, I expect) that I can get the sound to work by
running a patch cable from the sound output of the TV tuner card to one
of the inputs on my sound card.  I don't happen to have a patch cable
handy, so I haven't tried this yet.  But now I wonder: can I get the TV
audio to play via software, without a hardware connection to the sound
card?

Right now I have the bttv and snd-bt87x drivers inserted.  I'm using
ALSA, and in kmix there's an entry for the Bt878 sound card.  It has
just one mixer, "Capture" output, which is at full volume.  But, I don't
hear anything yet.  I've turned on and up all of the input channels on
my sound card, but no luck.

So somehow I need to connect the TV tuner output to the sound card
input, in software.  Can anyone help?

Thanks,
Andrew.

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bttv audio?

Post by Clemens Ladisc » Thu, 18 Nov 2004 17:58:36



> Right now I have the bttv and snd-bt87x drivers inserted.  I'm using
> ALSA, and in kmix there's an entry for the Bt878 sound card.  It has
> just one mixer, "Capture" output, which is at full volume.  But, I don't
> hear anything yet.

The snd-bt87x/btaudio drivers allow you to capture the audio (to a
file).  On many cards this function isn't implemented anyway.

Best regards,
Clemens

 
 
 

bttv audio?

Post by Arno Wagne » Sat, 27 Nov 2004 08:23:41



Quote:> I have a cheapo Bt878 TV tuner card-- an AITech WaveWatcher TV-PCI.  It
> cost $10 and it works, so I'm happy.  That is, the video works, but so
> far the audio doesn't.
> I know (or at least, I expect) that I can get the sound to work by
> running a patch cable from the sound output of the TV tuner card to one
> of the inputs on my sound card.  I don't happen to have a patch cable
> handy, so I haven't tried this yet.  But now I wonder: can I get the TV
> audio to play via software, without a hardware connection to the sound
> card?

On my bttv card Audio comes more or less directly from the tuner and
cannot be captured on the card. This is not a driver issue, there
is just no electonics on the card that would turn the audio to digital.

Quote:> Right now I have the bttv and snd-bt87x drivers inserted.  I'm using
> ALSA, and in kmix there's an entry for the Bt878 sound card.  It has
> just one mixer, "Capture" output, which is at full volume.  But, I don't
> hear anything yet.  I've turned on and up all of the input channels on
> my sound card, but no luck.
> So somehow I need to connect the TV tuner output to the sound card
> input, in software.  Can anyone help?

Depending on the hardware, it may be findamentally impossible.
AFAIK the BT-chip itself does not have sound capture.

Arno
--
For email address: lastname AT tik DOT ee DOT ethz DOT ch
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  "The more corrupt the state, the more numerous the laws" - Tacitus

 
 
 

bttv audio?

Post by Vampire at Wicked Empir » Sat, 27 Nov 2004 16:45:28



> Right now I have the bttv and snd-bt87x drivers inserted.  I'm using
> ALSA, and in kmix there's an entry for the Bt878 sound card.  It has
> just one mixer, "Capture" output, which is at full volume.  But, I don't
> hear anything yet.  I've turned on and up all of the input channels on
> my sound card, but no luck.

> So somehow I need to connect the TV tuner output to the sound card
> input, in software.  Can anyone help?

> Thanks,
> Andrew.

You need a program that read the output of bt878 and write the output to
   your sound. This causes CPU load and cause difficulty to TV recording
program.

It is easier to buy/build a cord to connect the TV card and sound card.

--
My projects:
   http://www.csie.nctu.edu.tw/~cp76/gcin
   http://fftv.sf.net
   http://tcron.sf.net
   http://www.csie.nctu.edu.tw/~cp76/gcb

 
 
 

bttv audio?

Post by Jared Richardso » Sat, 04 Dec 2004 03:43:17




>> I have a cheapo Bt878 TV tuner card-- an AITech WaveWatcher TV-PCI.  It
>> cost $10 and it works, so I'm happy.  That is, the video works, but so
>> far the audio doesn't.

>> I know (or at least, I expect) that I can get the sound to work by
>> running a patch cable from the sound output of the TV tuner card to one
>> of the inputs on my sound card.  I don't happen to have a patch cable
>> handy, so I haven't tried this yet.  But now I wonder: can I get the TV
>> audio to play via software, without a hardware connection to the sound
>> card?

> On my bttv card Audio comes more or less directly from the tuner and
> cannot be captured on the card. This is not a driver issue, there
> is just no electonics on the card that would turn the audio to digital.

>> Right now I have the bttv and snd-bt87x drivers inserted.  I'm using
>> ALSA, and in kmix there's an entry for the Bt878 sound card.  It has
>> just one mixer, "Capture" output, which is at full volume.  But, I don't
>> hear anything yet.  I've turned on and up all of the input channels on
>> my sound card, but no luck.

>> So somehow I need to connect the TV tuner output to the sound card
>> input, in software.  Can anyone help?

> Depending on the hardware, it may be findamentally impossible.
> AFAIK the BT-chip itself does not have sound capture.

> Arno
> --
> For email address: lastname AT tik DOT ee DOT ethz DOT ch
> GnuPG: ID:1E25338F FP:0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
>  "The more corrupt the state, the more numerous the laws" - Tacitus

I have this card and "solved" this problem. I'm at work and the machine is
at home, so I'll try to muddle through how to make it work.

the short version is you need to load the module with audiomux=0

The longer version... unload the module, edit you modules.conf and add the
audiomux=0 to your bttv line, then reload the module.

I have noticed that once you reboot, it doesn't always work, so I've once
had to unload the module and then reload it before the audio worked.

As an aside, I'm using this card in a MythTV system and it's working great.

 
 
 

bttv audio?

Post by Andrew Schulma » Sat, 04 Dec 2004 04:25:54


Quote:> >> can I get the TV
> >> audio to play via software, without a hardware connection to the sound
> >> card?

> the short version is you need to load the module with audiomux=0

Thanks, I'll try this when I get home.  Two questions:

When you say "the module", you're talking about bttv and not snd-bt87x?

Do you know which mixer channels the TV sound comes in on?

Thanks,
Andrew.

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bttv audio?

Post by Jared Richardso » Sun, 05 Dec 2004 05:34:51



Quote:>> >> can I get the TV
>> >> audio to play via software, without a hardware connection to the sound
>> >> card?

>> the short version is you need to load the module with audiomux=0

> Thanks, I'll try this when I get home.  Two questions:

> When you say "the module", you're talking about bttv and not snd-bt87x?

Sorry, yes "bttv"

Quote:> Do you know which mixer channels the TV sound comes in on?

I do not... I'm using Knoppix... KMix has a television channel but I haven't
confirmed that it's being used.


read this group. When you get it working, we can post the results for
posterity (and Google!) here.

 
 
 

bttv audio?

Post by Jared Richardso » Tue, 07 Dec 2004 14:02:34





>>> >> can I get the TV
>>> >> audio to play via software, without a hardware connection to the
>>> >> sound
>>> >> card?

>>> the short version is you need to load the module with audiomux=0

>> Thanks, I'll try this when I get home.  Two questions:

>> When you say "the module", you're talking about bttv and not snd-bt87x?

> Sorry, yes "bttv"

>> Do you know which mixer channels the TV sound comes in on?

> I do not... I'm using Knoppix... KMix has a television channel but I
> haven't confirmed that it's being used.

> If you don't get it working, send me mail at j a r e d . r i c h a r d s o

> regularly read this group. When you get it working, we can post the
> results for posterity (and Google!) here.

in /etc/modules-2.4.7 change the line "bttv" to be
bttv -card=27 audiomux=0
 
 
 

bttv audio?

Post by Andrew Schulma » Tue, 07 Dec 2004 19:31:13


Quote:> I know (or at least, I expect) that I can get the sound to work by
> running a patch cable from the sound output of the TV tuner card to one
> of the inputs on my sound card.  I don't happen to have a patch cable
> handy, so I haven't tried this yet.  But now I wonder: can I get the TV
> audio to play via software, without a hardware connection to the sound
> card?

Thanks to everyone who answered.  I tried all of the suggested fixes, but no
luck.  So maybe my cheapo tuner card is hardware crippled, as Arno
suggests.  Anyway, I stopped at Radio Shack yesterday and bought a $4 patch
cable, and the audio works fine now.  Thanks everyone!

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1. bttv audio issue

Hi
I have a problem I have built in 'c' a simple app which dumps images from
the bttv card to the jpeg file. I would now like to create mpeg with audio
and video together. I have two questions:
- what is the library suggested to use to create mpeg files
- how to get the sound and combine with video to make a synchronized stream,
I think I can use bttv ioctl but how to retrieve the sound buffer then I do
not know, does somebody has a few line of example code how to best do this.

Regards Tomek

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