please help ..The New DDE_USB is giving compilation errors...

Dirk Vogt dvogt at
Fri Apr 10 17:44:04 CEST 2009


> 1) For usb camera a dope has started and a small menu has came showing
> "usbcam" and "exit". But it is not showing anything when I am clicking
> on usbcam.

That's the normal behavior of usbcam, when it does not find a usbcam.

However you should see in the debugging console that usbcore and have
usbcam are initialized. 

When usbcam recognizes a new cam, a new button video0 will appear. By
clicking this button usbcam will start the video capture.

> 2) For usbhid , we have connected a usb mouse . But it was not
> working. Here is the menu.lst , I have used for usb mouse.

It seems you forgot to put usbcore into your menu.lst.  Remember, DDEUSB
uses a client/server approach to offer USB functionality.  The usbcore
is the only one to touch the host-controller hardware and thus needed
for all other USB drivers. 

> Please know that we have a plan to add support for new webcams .
> Please let us know following information :
> 1) Please provide us the menu.lst which you have used for usbcam and usbhid.

They do not differ much from yours. 

> 2) I have found following files under directory
> "/home/tapas/10AprilUserbuild/source/pkg/usb/examples/usbcam/src"
> main.c , support.c , usbcam.c  and libv4lconvert (directory)

Actually usbcam.c is just containing the gui and the v4l and v4l2
capturing code. The first should be documented somewhere in the dope
package and for the second there is plenty of documentation including
small examples spread all over the world wide web.

the libv4lconvert was taken from libv4l [1] and was needed to convert
the data from the video device from e.g. jpeg to the vscreen's pixel
format.  Further, support.c implements some functions the were needed by
linux kernel part of V4L. 
If you have a look at the makefile, you can probably see how to add
support for new usbcams.

Good luck,


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