Question - Component input via software card

Question - Component input via software card

[Sam Logen]

Hi.  I've got a theoretical question I just wanted to
pass by you all.

Now, software capture cards collect raw information
from their video and audio composite jacks, right? 
Then the software processes these streams into a file.
 Would it be possible to connect component cables from
a high def. video source to the video and audio
composite plugs of the capture card, and have a
program process the three streams together as video
streams instead of video and audio streams, then save
the result in a file?  Audio can be captured
elsewhere, such as by an audio-in plug.

Or would the hardware on the capture card filter out
anything it would not perceive as audio?

I'm not taking into consideration processing power or
hard drive access bottlenecks, or other hardware
limitations beyond the capture card.

Thanks guys.
Sam.


      

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Re: Question - Component input via software card

[Daniel Gimpelevich]

Sam Logen <starz909 <at> yahoo.com> writes:

>  Would it be possible to connect component cables from
> a high def. video source to the video and audio
> composite plugs of the capture card, and have a
> program process the three streams together as video
> streams instead of video and audio streams, then save
> the result in a file?

That would not be possible with any off-the-shelf composite capture card, but it
would be possible to design your own capture hardware that could use the same
plugs for either audio or component video. Just getting a Hauppauge HD-PVR would
likely be cheaper.

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Re: Question - Component input via software card

[Daniel Glöckner]

On Tue, Jun 03, 2008 at 01:55:07PM -0700, Sam Logen wrote:
> Now, software capture cards collect raw information
> from their video and audio composite jacks, right? 

Some capture cards can collect raw information.

> Then the software processes these streams into a file.

No, drivers make the card process the raw data for normal use.
This is too much to be done in software.

>  Would it be possible to connect component cables from
> a high def. video source to the video and audio
> composite plugs of the capture card, and have a
> program process the three streams together as video
> streams instead of video and audio streams, then save
> the result in a file?

Baseband audio inputs are usually sampled at a much lower frequency than
video inputs.
And if audio is not input as baseband signal, there is only one ADC.

> Or would the hardware on the capture card filter out
> anything it would not perceive as audio?

In baseband audio there may be an analog low pass filter corresponding
to the low sampling rate.

I don't know any chip that captures raw modulated audio.
But on the other hand I don't know that many chips.

> I'm not taking into consideration processing power or
> hard drive access bottlenecks, or other hardware
> limitations beyond the capture card.

It is a bit difficult to consider the limitations of an unknown capture
card.

  Daniel

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Re: Question - Component input via software card

[Sam Logen]

--- Daniel Gimpelevich
<daniel@gimpelevich.san-francisco.ca.us> wrote:

> Sam Logen <starz909 <at> yahoo.com> writes:
> 
> >  Would it be possible to connect component cables
> from
> > a high def. video source to the video and audio
> > composite plugs of the capture card, and have a
> > program process the three streams together as
> video
> > streams instead of video and audio streams, then
> save
> > the result in a file?
> 
> That would not be possible with any off-the-shelf
> composite capture card, but it
> would be possible to design your own capture
> hardware that could use the same
> plugs for either audio or component video. Just
> getting a Hauppauge HD-PVR would
> likely be cheaper.

I hadn't heard of that.  I haven't been paying
attention to latest hardware releases.  But can you
explan why my suggestion wouldn't be possible?  I've
no doubt you're right, I'd just like to hear why. 
That HD-PVR looks the way to go, but adding that thing
looks like it will up my cabinet temp by 20 degrees.

Sam


      

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Re: Question - Component input via software card

[Christoph Willing]

On 05/06/2008, at 8:33 AM, Sam Logen wrote:

>
> --- Daniel Gimpelevich
> <daniel@gimpelevich.san-francisco.ca.us> wrote:
>
>> Sam Logen <starz909 <at> yahoo.com> writes:
>>
>>>  Would it be possible to connect component cables
>> from
>>> a high def. video source to the video and audio
>>> composite plugs of the capture card, and have a
>>> program process the three streams together as
>> video
>>> streams instead of video and audio streams, then
>> save
>>> the result in a file?
>>
>> That would not be possible with any off-the-shelf
>> composite capture card, but it
>> would be possible to design your own capture
>> hardware that could use the same
>> plugs for either audio or component video. Just
>> getting a Hauppauge HD-PVR would
>> likely be cheaper.


Another relatively cheap option for HD component input is the  
Blackmagic Intensity Pro - see:
	http://www.blackmagic-design.com/products/intensity/
It has HDMI input too.

Unfortunately they don't provide a Linux driver and have stated  
they're not interested in doing so. Any chance of producing a driver  
without their help?



chris


Christoph Willing
University of Queensland




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Re: Question - Component input via software card

[Sam Logen]

> It is a bit difficult to consider the limitations of an
> unknown capture
> card.
> 
>   Daniel

I know, I've just been scavenging a/v cables to rewire a few entertainment centers, and this idea came to mind, so I thought I'd pass it on.  Thanks for the replies.

Sam


      

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