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Re: Quicktime VDig, Async calls

Can anyone tell me if VDGrabOneFrameAsync is still supported by QT  
and the sequence grabber?  I've written a VDIG that supports this,  
but it is never called...  My DeviceInfo returns  
digiOutDoesAsyncGrabs as part of info->outputCapabilityFlags.

I *do* see that VDGrabOneFrame is called. Straight after a call to  
VDDone returns 'true' (it returns true because the seq.grabber has  
not requested any async gets yet)

I don't understand at all why the functions not being called.
Can anyone help?

I suspect GrabOneFrameAsync may have some other pre-required setup/flag combination before it would be called but I don't have sources with me to dig around in...however, both GrabOneFrame and GrabOneFrameAsync are no longer recommened as documented in the SoftVDigX sample (if you haven't seen it you should take a look). Use the compress source model, QT treats everything as some type of compressed source (yes, even uncompressed yuv and rgb pixels) and the required selector set, and setup are far less confusing not to mention that it's the recommended approach.

For your reading enjoyment if you're curious, here's a link to the holy grail of vdig documents...circa 1993 QuickTime 1.5. SoftVDigX borrows a great deal of information from this document.
http://www.cs.unc.edu/Research/stc/FAQs/1394Firewire/Apple/king_woodcock_final.html

regards,
edward

 Edward Agabeg
 WWDR Engineer
 QuickTime and Audio
 Worldwide Developer Relations
 Apple

 http://www.apple.com/developer
 http://www.apple.com/quicktime

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