[IOXperts Video-Developers] Re: OK, now how about ->two<- QuickCams?

[rob shaw]

>At 2:00 PM -0700 1/9/04, rob shaw wrote:
>>However, we're trying to get ->two<- QuickCam Orbits to works simultaneously.
>>We have so far gotten the two Orbits to pan and tilt simultaneously,
>>by calling FindNextComponent() twice, getting a ComponentInstance
>>for both 'vdig's, and using your USB driver.  But there seems to be
>>only one SeqGrabComponentType, or 'barg' available, so we can only
>>call FindNextComponent() once with that selector, and get only one
>>or the other of the cameras.  We're hoping this is easy!
>
>It's not. :-/
>
>There's only one sequence grabber _component_ available, but you can
>open multiple _instances_ of it. (Opening a component multiple times
>gives you multiple instances)
>
>Once you have 2 SG instance, you need to make sure that each one is
>talking to a different camera -- the relevant call is
>SGSetVideoDigitizerComponent().
>
>There was a thread on this on the Apple QuickTime API list a few
>months back -- someone was doing stereo video -- I think he may be on
>this list.
>
>In any case, this should get you going in the right direction.
>
>Let me know if you have any problems -- I want to make sure this
>works correctly, but we don't have any good test code.
>
>Thanks,
>
>-Steve
>

Thanks, Steve!

I was able to get a second "instance", and change which camera the sequence
grabber
was looking at by using SGSetVideoDigitizerComponent().  However, when I
tried to
just run a parallel window in the minimung example, opening a second
gworld, etc.
things were error-free until the last step, SGStartRecord() on the second
instance,
when I got error -6981, "not enough bandwidth".  This makes some sense, as
we're
pushing the USB bandwidth, but I'd be happy to get half the frame rate in
each window.

I'll try looking in the quicktime archives, but I'm on a modem, and the
search engine
and/or the connection is very sluggish.  I have a friend with a DSL
connection, and
will try this weekend...

Any and all suggestions welcome!

rob