Changing sequence graber´s video imput

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Antrox - 22 Nov 2006 17:07 GMT

Hi!
I´m using some cammeras (at this moment isigth and usb cammera) which
I preview their captures. I would like to be able to change the imput
source of each sequence graber asocite to a graphic world where I
preview the imput videos. How can I do this? I´ve tryed video
digitizer component and it dosen´t work. How could I know how many
video devices are enable and I could change to them in execution time?
Could I represent same video imput in two windows? (I don´t know if I
need two seq grabbers, or two graphic worlds, or it can´t be possible)

Thanks.

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David Phillip Oster - 23 Nov 2006 06:38 GMT

> I´m using some cammeras (at this moment isigth and usb cammera) which
> I preview their captures. I would like to be able to change the imput
[quoted text clipped - 4 lines]
> Could I represent same video imput in two windows? (I don´t know if I
> need two seq grabbers, or two graphic worlds, or it can´t be possible)

It is you. I've never had any trouble with the preview stream of
quicktime sequence grabber components, and i've never had trouble
installing a bottleneck procedure to have them render each frame to an
offscreen GWorld, that I can then map to as many windows as I want.

If you've got multiple cameras, you can ask Quicktime to enumerate the
video digitizer components that are available.

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Antrox - 24 Nov 2006 10:39 GMT

Hi David, thaks for your answer.

I´m using
err = SGGetChannelDeviceList(videoChannel1, sgDeviceListIncludeInputs,
&list1);
on every videoChannel for descovering which imputs are available but I
don´t understand how to change imput channel to a enable imput i have
in the list struct. Has anyone an example in carbon?

Thanks.

David Phillip Oster ha escrito:

> > I´m using some cammeras (at this moment isigth and usb cammera) which
> > I preview their captures. I would like to be able to change the imput
[quoted text clipped - 12 lines]
> If you've got multiple cameras, you can ask Quicktime to enumerate the
> video digitizer components that are available.

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David Phillip Oster - 26 Nov 2006 00:18 GMT

> David Phillip Oster ha escrito:
>
[quoted text clipped - 14 lines]
> > If you've got multiple cameras, you can ask Quicktime to enumerate the
> > video digitizer components that are available.

> Hi David, thaks for your answer.
>
[quoted text clipped - 6 lines]
>
> Thanks.

Did you look at Apple's sample source:

http://developer.apple.com/samplecode/HackTV_Carbon

I've mostly been working from:

http://developer.apple.com/samplecode/WhackedTV

which does supports arbitrary numbers of source SGChannels. It is in
Objective-C, but as long you know that the objective-C expression:

[obj func:arg] is equivalent to the C++ obj->func(arg) or the C
func(obj, arg) you'll be able to read the code, and the Objective-C is
mostly wrapper for the C api.

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Mac Forum / Programming / Mac Programming / November 2006

Changing sequence graber´s video imput