On 6/1/06, pratapg <[EMAIL PROTECTED]> wrote: > I am Pratap.G from PUNE IIIT and I am currently working on the web > camera based digital image acquisition system. I havent choosen vendor for > web camera and I need multiple cameras to have the multiple views of the > image in visual monitoring systems.
Pratap, You mentioned needing multiple cameras for image acquisition. Webcams are probably not your best choice for doing this. It's cheaper and probably more efficient to use any BT878 based PCI card. These are well supported in linux. A typical BT878 board will cost you around RS1000 (USD$25) and provide a minimum of 4 camera inputs which you can then feed with the cheap BNC cameras that you'll find used in typical CCTV solutions. > I am working on RH linux2.4. Please kindly suggest how to start the I would highly recommend first switching over to something more recent like 2.6.1x which most current distributions carry. > work for writing USB web cam drivers. > You mentioned you haven't chosen a webcam yet. If you really have to use webcams, I would first recommend picking one of the webcams that already has linux support. Look here for a list of the drivers in the mainline kernel: http://www.linux-m32r.org/lxr/http/source/drivers/media/video/ Mauro's tree has several drivers which are not mainline yet: http://www.linuxtv.org/hg/v4l-dvb If your goal is still to write a usb webcam driver for a webcam that's not yet supported, then here's what I recommend: 1. Read LDD3 chapter on USB, http://lwn.net/Kernel/LDD3/ 2. Get the webcam working on windows with a simple testapp, then use a usb sniffer like usbsnoop to trace the usb transfers between the webcam and windows (unless of course you are fortunate enough to have chip specifications) 3. Identify the important parts of that trace that setup the camera, these will tend to be a sequence of register read/writes that are done on initialization 4. Identify the image portion of the usb transfers, this will typically be RGB or Bayer format data, or maybe JPEG/MJPEG in more recent models. Worst case it'll be some unusual proprietary compression in which case, study the pwc drivers, I think. 5. Write a driver for it based on examples in the directory mentioned above. Make sure to use V4L2 rather than V4L1 since V4L1 is to be end-of-lifed soon. Enjoy, jayakumar _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
