View Full Version : Text Overlay

May 13, 2002, 19:03:44
Hi there,

I’m looking for an VFW SDK that will allow me to create an application that can grab images at 1 fps and overlay text on those images and then store the images in a sequential video file.

Basically I’m setting up a surveillance system that monitors events over a geographical range. So the image taken would be in a different geographic position everytime. Therefore it would be nice to have GPS data overlayed on the video image.

It would be nice to then review the captured images as one file - perhaps in AVI format of MotionJPEG. I'm using VB as the development platform.

Another thing is that I will need to have the capture application load the video codec automatically instead of going through a video compression/codec dialog each and every time.

Any ideas on how to implement this? Would IC Imaging controls work in this scenario?

Sorry for the wholloping post - but if IC imaging will do the trick then I can stop myself from attending a stress management class :)


Willem Buitendyk

This message was originally posted by Willem Buitendyk in the old IC Imaging Control Support Forum.

May 24, 2002, 15:57:31
First of all, I would like to point out that IC Imaging Control can be used only with WDM streaming compliant devices. VfW devices do not allow the realisation of IC Imaging Controls core functionality (like changing the parameters of a video capture device with your own program). Therefore VfW devices are not supported. Today, most devices have a WDM streaming driver in addition to a VfW driver and can be used with IC Imaging Control.

With IC Imaging Control, you are able to write a video stream to an AVI file using a codec. It is also possible to set the parameters of a codec by software (no need to display a parameter dialog all the time). But there is currently no way to render an overlay in the frames that are written to an AVI file. We plan to integrate this feature in the next version.

With version 1.3, the solution to the problem is the following:
1) Start the live video in single grab mode and grab one image every second.
2) Render the overlay inforamtion in every image buffer and write the buffer to disk as a bmp file. There is a sample program in source code that shows how to render text into an image buffer.

3) Use a tool (i.e. QuickTime for Windows contains such a tool) to convert the bmp files to an AVI file.

If you are used to Windows API programming in VB, you could write your own AVI saving function and pass the image buffers to this function. But I have to admit that this way takes a lot of experiance in Windows API programming.

Best regards
IC Support

This message was originally posted by IC Support in the old IC Imaging Control Support Forum.