revVideoGrabber: stop preview doesn't hide video window

Ben Rubinstein benr_mc at
Sat Aug 7 11:35:14 EDT 2010

Thanks for the confirmation Richard, I've added a report to RQCC for this issue.

I'm a bit perturbed by the combination of the "The PC side works much better 
than the Mac side" with "runs with adequate stability even for video grabs as 
long as 3-5 minutes".  The latter seems to me to be a doubly low standard: 
"adequate stability" and "as long as...".

So far my testing (on Mac) with a rig cycling round initialising, setting 
settings, preview, capture (for short capture runs at this point, ie 5 
seconds) and closing the video grabber has captured approx 2,000 clips over a 
nine hour period without evident issues.  Should I infer from your remarks 
that I got lucky?  Is it long grabs (my next set of tests) that is the problem?

Many thanks,


On 06/08/2010 00:38, Richard Miller wrote:
> Ben,
> We use the video grabber functions extensively in our software, but only
> on PC's (where it runs with adequate stability even for video grabs as
> long as 3-5 minutes). The PC side works much better than the Mac side.
> The issue you are running into on a Mac is a known bug. You're not doing
> anything wrong. But I've not found it a problem to use
> revCloseVIdeoGrabber as often as needed (on Mac or PC side)... because
> you are right in saying it is the only way to get rid of the preview
> image on a Mac.
> Richard Miller
> On 8/5/10 5:39 PM, Ben Rubinstein wrote:
>> Docs for revStopPreviewingVideo says:
>> "Stops showing input from a video camera in the video grabber window."
>> "Use the revStopPreviewingVideo command to stop showing video input."
>> "When you stop previewing video, the video grabber window shows a
>> blank screen."
>> When I try this (rev 4.0 or later, on MacOS X 10.6) it doesn't show a
>> blank screen, instead I'm left with a still of the last frame. The
>> only way to make it go away is to execute revCloseVideoGrabber.
>> Is this a known bug? Am I doing something wrong? Does anyone else
>> experience this, or conversely has anyone experience of it working as
>> documented?
>> TIA,
>> Ben

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