[mythtv-users] Multiple capture cards and audio

[James L. Paul]

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On Tuesday 25 November 2003 13:22, Douglas Phillipson wrote:
> Am I correct in assuming that if you want to record two simultaneous
> programs, you have to have capture cards with audio  capture capability
> like a PVR-250/350.

Generally, all TV capture cards also capture audio, it's more a matter of how 
you route the audio and what drivers are available.

> Is it possible to capture two streams with two Wintv Go boards,assuming
> CPU is fast enough, using just the audio circuitry on the MOBO?  I would
> assume not.

It depends on the driver support for the audio capture chip on the TV card. 
For example, if you have a bttv card that works with btaudio, then you can 
capture audio directly. Otherwise you need to cable to analog audio to a 
sound device that you can capture from.

> Do these WinTV Go boards have audio capture capability?

I have 3 different WinTVGo cards, and mine all work with btaudio. I don't 
believe all models/versions of WinTVGo support this, I've heard that some 
have different chipsets or broken compatibility.

> I was getting audio from the line out on the Wintv Go board during
> capture and during use by xawtv.  Does that mean it can capture audio?

Yes. But it doesn't mean your particular board will support btaudio. Since you 
apparently have it working with bttv, it's a good bet it will work fine.

> Do I need a cable between capture card and mobo sound input with Wintv
> Go board?

Only if you are not capturing audio directly from the WinTVGo card. If the dsp 
device you will record from is a sound card, you will need to use a cable to 
get the TV audio to a sound card input.

> The FAQ states:
>
> NOTE: The PVR-250/350 does not require a sound card for audio capture.

True. This is for somewhat different reasons though. Video and audio are not 
captured separately with these cards, they output a fully multiplexed MPEG2 
program stream, which includes audio.

> Does this mean the cheaper Hauppage WinTV Go board does require either
> MOBO audio or separate audio card for each capture card?

If you can use a driver such as btaudio to bind a dsp device to the capture 
card's sound output, then you don't need a sound card for capturing, only for 
playback. If you have no such method, then you need to cable to analog audio 
to a device that you _can_ capture from, like a sound card. You need a 
solution for each TV card, so if you have 2 cards that you can't directly 
bind dsp devices to, then you would need 2 other devices you can do this with 
and cable the audio to their inputs.

> Being somewhat short on slots, if you have to have 2 audio devices, can
> one be the MOBO device and the other be a Sound board?

Yes. assuming you have drivers to support whatever combination you have, all 
you need to do is get the audio bound to a dsp device you can read from. 
Whether that device is a driver that reads directly from the TV card or from 
some other sound device that you've cabled the audio to doesn't matter much.

> Thanks
>
> Doug P
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