Emulating a WebCamera
in [Device Drivers]
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From: pradeep_TP on 11 Jan 2006 08:06 Hi all, Recently I came across a software that can emulate a web camera. It is by the name virtualcamera and seems to be a very famous software. I did not find any other software which can do the same thing. It seems its some kind of magic!. I have installed a TV Tuner Card and Web cam on my PC. My yahoo messenger detects both these as valid WebCams. When i installed virtualWebCam i saw yahoo nicely detected that as well. I want to create a similar software on my own and want to know how far i can get with it. Does anyone have any good suggestions for me about where to start. I will drop the idea altogher if you say upfront that it can only be created by big companies with 'black box' information on the same. I am want an honest reply from expereinced developers about this. My summarised questions are as follows 1) whether is it possible for a single developer for me to do this. 2) I have fair knowledge of Visual C++ and good knowledge of C#. 3) Is it a task in the context of device driver programming. Thanks all pradeep_tp
From: Cat on 11 Jan 2006 13:24 1) Anything is possible. 2) It will probably be a bit of a challenge, then. 3) It's one way of doing it, but I don't think it is the only way. In fact, I wouldn't do it that way myself. My experience with something like this is limited, but what I have done is create a program that can capture the uncompressed Webcam video streams right before it is compressed for transmission over the network. (This was done by hooking VFW.) I can suggest that before you attempt to emulate a webcam, that you try to use one. As far as I can see, there are two main interfaces used nowadays for Webcams under Windows: VFW (Video for Windows) and DirectShow. VFW is somewhat old and deprecated, but still present in Windows and used by some applications. I found a couple example capture programs on Codeproject: With DirectShow: http://www.codeproject.com/directx/LiveVideo.asp http://www.codeproject.com/csharp/webcamservice.asp (C#) http://www.codeproject.com/audio/DXCapture.asp With VFW: http://www.codeproject.com/webservices/webcam.asp (take a look at the "Server" component, CWebCap.cpp) Good luck, -Cat
From: pradeep_TP on 12 Jan 2006 00:10 Hello Cat, Thank you for showing interest in this thread. I have already gone through all the codes that are available in codeproject, but all of them only discuss about how to capture the images from the video. None of the articles discusses about creating something like a web cam on device driver level. Why i m emphasizing on the device driver part is because when i checked the files installed by the software, i find that there is a file with extension .sys which is a driver file. Moreover I can see it installed as a driver in the dever drivers list under "sound, video, game controls". I am interested in that part, i.e how do you emulate a device. Even though a web camera is not present physically, the software has been able to emulate the device and other applications, like yahoo IM, detected it as a device which can give video outputs. Thanks pradeep_tp "Cat" wrote: > 1) Anything is possible. > 2) It will probably be a bit of a challenge, then. > 3) It's one way of doing it, but I don't think it is the only way. In > fact, I wouldn't do it that way myself. > > My experience with something like this is limited, but what I have done > is create a program that can capture the uncompressed Webcam video > streams right before it is compressed for transmission over the > network. (This was done by hooking VFW.) > > I can suggest that before you attempt to emulate a webcam, that you try > to use one. As far as I can see, there are two main interfaces used > nowadays for Webcams under Windows: VFW (Video for Windows) and > DirectShow. VFW is somewhat old and deprecated, but still present in > Windows and used by some applications. I found a couple example capture > programs on Codeproject: > With DirectShow: > http://www.codeproject.com/directx/LiveVideo.asp > http://www.codeproject.com/csharp/webcamservice.asp (C#) > http://www.codeproject.com/audio/DXCapture.asp > > With VFW: > http://www.codeproject.com/webservices/webcam.asp (take a look at the > "Server" component, CWebCap.cpp) > > Good luck, > -Cat > >
From: Anonymous on 12 Jan 2006 07:33 In the ddk you will find usbintel, this is source code of intel webcam. If you can understand this code then you are plain sailing to write the emulator. "pradeep_TP" <pradeepTP(a)discussions.microsoft.com> wrote in message news:1A9CDCD4-F2A4-42FE-9C08-49F188D935C5(a)microsoft.com... > Hello Cat, > > Thank you for showing interest in this thread. I have already gone through > all the codes that are available in codeproject, but all of them only discuss > about how to capture the images from the video. None of the articles > discusses about creating something like a web cam on device driver level. Why > i m emphasizing on the device driver part is because when i checked the files > installed by the software, i find that there is a file with extension .sys > which is a driver file. Moreover I can see it installed as a driver in the > dever drivers list under "sound, video, game controls". > > I am interested in that part, i.e how do you emulate a device. Even though a > web camera is not present physically, the software has been able to emulate > the device and other applications, like yahoo IM, detected it as a device > which can give video outputs. > > Thanks > pradeep_tp > > "Cat" wrote: > > > 1) Anything is possible. > > 2) It will probably be a bit of a challenge, then. > > 3) It's one way of doing it, but I don't think it is the only way. In > > fact, I wouldn't do it that way myself. > > > > My experience with something like this is limited, but what I have done > > is create a program that can capture the uncompressed Webcam video > > streams right before it is compressed for transmission over the > > network. (This was done by hooking VFW.) > > > > I can suggest that before you attempt to emulate a webcam, that you try > > to use one. As far as I can see, there are two main interfaces used > > nowadays for Webcams under Windows: VFW (Video for Windows) and > > DirectShow. VFW is somewhat old and deprecated, but still present in > > Windows and used by some applications. I found a couple example capture > > programs on Codeproject: > > With DirectShow: > > http://www.codeproject.com/directx/LiveVideo.asp > > http://www.codeproject.com/csharp/webcamservice.asp (C#) > > http://www.codeproject.com/audio/DXCapture.asp > > > > With VFW: > > http://www.codeproject.com/webservices/webcam.asp (take a look at the > > "Server" component, CWebCap.cpp) > > > > Good luck, > > -Cat > > > >
From: Cat on 12 Jan 2006 15:35
Generally, I stay away from kernel-mode as much as possible, the reason being that crashes in kernel-mode are a lot more time-consuming to debug than in usermode, where you can simply attach a debugger, terminate the process, etc. That's why I was pointing toward a user-mode solution. If, however, you genuinely need the device to show up in Device Manager, etc., etc., then indeed kernel-mode seems like the only solution. Good luck, -Cat |