[mythtv-users] Onboard sound full-duplex ?

Maarten mythtv at ultratux.org
Wed Oct 13 21:20:50 UTC 2004

On Wednesday 13 October 2004 22:00, Mark J. Small wrote:
> On October 13, 2004 04:27 pm, Isaac Richards wrote:
> > On Wednesday 13 October 2004 03:06 pm, Maarten wrote:
> > > On Wednesday 13 October 2004 20:28, Isaac Richards wrote:

> Lots of confusion here,  I'll see if I can clear it up.
> (1) Yes, the onboard Via sound IS full duplex.

Oh really, it _is_ ?  That's good -albeit a bit confusing- news !
When I started with Mythtv back in march I tried with two BT8x8 cards (and the 
two sound cards obviously) but due to a broken BT878 card (or tuner issue) 
which could not tune well I had to scrap that 2-card idea.  But at that time 
I found that when using the onboard sound I got sound-less recordings, even 
when playing back later with a different setup / card.  The little jumper 
cables were connected correctly, as were the mixer and capture settings.
But that was a complicated and error-prone setup then, so I must assume I 
overlooked something.  I'm much more familiar with mythtv now, therefore I 
decided to buy a well-supported second card and try the 2-card thingy again. 
The PVR 250s are a bit too expensive for me here in europe, and I wanted to 
avoid any possible confusion mixing mpeg4 and mpeg2 recordings and/or 
transcoding, although people will no doubt point out that there are none. ;-)

> (2) No it doesn't matter in this case

As I gathered from Isaac.  Thanks for clearing this up, too.

> To capture the audio part of your video stream on a bt878, you don't need a
> sound card at all, you can use the bt878 sound capture hardware.  Mythtv
> will record it directly to the nuv file along with the video source.

Possibly, but for now I use the short jumper cables that connect each BT8x8 
card sound output to a respective soundcard input, so I _do_ need two 
soundcards.  I never tried the <whatsitsname> module to cap the sound 
directly off the hardware. I remember reading somewhere that that only works 
with BT878 cards as opposed to BT848 cards which I currently run with...

Thanks for your info!


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