Re: How to Access hardware buffers thru DShow Interfaces / other Apis?
- From: "Max Paklin" <mpaklin@xxxxxxxxxxx>
- Date: Tue, 25 Jul 2006 13:29:31 -0700
Why is it a problem? From what I can understand everything appears to be
working as designed.
The thing is that the driver that keeps the settings your application
applied is loaded all the time while the hardware is connected. So that fact
that you exited your application doesn't mean anything to the driver. The
driver has the single instance of its data and that equals to the state of
hardware. It is not per application.
-- Max.
"courierpt" <courierpt@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:16FEBD23-26C1-49E7-9277-612A2954FDE2@xxxxxxxxxxxxxxxx
Hi,
I am a newbie to DirectShow. Recently I am developing an Image Acquisition
software for a microscope. I use IAMVideoProAmp to Get/Set the properties
to
control the video display. I get the properties and save them in an ini
file.
I found a question:
1. I set the ColorEnable property to be the Auto mode to obtain a correct
color display;
2. then I switch the ColorEnable Item to be the Manual mode(after this,the
video display does not change the color);
3. now I save all the properties that I can get from IAMVideoProAmp.
4. However, when I restart my program to read the ini file to set the
saved
properties to the camera, the color display is not the original one.
The same procedures are taken by using vidcap32 except that the properties
can not be saved. Namely,
1. open the video source dialog to set the ColorEnable item to be the auto
mode to obtain a correct color display;
2. then switch it to manual mode (after this,the video display does not
change the color);
3. close the vidcap32.
4. If I restart the vidcap32, the color display remains the same as it was
before I close the vidcap32.
If the USB camera is connected to the PC or the PC is not turned off, no
matter how many times I restart the vidcap32 or my program, the display
will
not be changed(the ColorEnable property is manual mode); however, if the
camera is pluged off or the PC is restarted, the display color will be
shifted. I have checked the Registry but I did not find any solution.
Therefore, I guess that some properties that compensate the color display
are
buffered in the hardware rather than stored in the Registry to control the
display. How to get those parameters or access the related hardware
buffers
thru directshow interfaces?
Because I found a third software that is not specially designed for my
camera
can store the parameters to obtain the correct color display. I am curious
about how it achieves this.
Any comments should be appreciated!
.
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