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#1 Posted : Thursday, June 5, 2008 4:31:16 AM(UTC)

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I am working on a webcam snapshot program in Delphi using LeadTools Multimedia Eval 15. The goal is to use show a preview from the webcam, let the user take a snapshot, display the snapshot, and allow the user to either save or retake the snapshot.

The first issue is that the process of ltmmCaptureCtrl1.StartCapture has a noticable delay. There is an option for the user to change the video device they are using/previewing but this involves a call to StopCapture and StartCapture again.

The second issue is how to display the snapshot. Currently I save a bitmap to a temp file using ltmmCaptureCtrl1.SaveStillBitmap, and then load it into a TImage using Image1.Picture.LoadFromFile. While this works, I would prefer to do this within memory rather than writing and reading to the harddrive.



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#2 Posted : Sunday, June 8, 2008 2:23:49 AM(UTC)

Qasem Lubani  

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There will be a delay in preparing the capture device after you selected the device and the output filename. To minimize this, applications are typically doing something like this:

* select the device and the output filename
* call ReadyCapture (this will take some time, depending on the device)
* bring up a message box, asking the user when you start the capture
* call StartCapture (now the capture will start immediately, because ReadyCapture prepared the capture graph)

You cannot eliminate the initialization time for the capture device. But you can make it less annoying with the above technique.

As for saving the image to memory, you can use the GetStillPicture method.

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