View and capture webcam input

[Sebastian-Nicolae Matei]

Hello,

I started working with the InfTee to preview and capture the input of a
webcam. Somehow I didn't manage getting it to work.
This is what I have up to now:

private IBaseFilter FindCaptureDevice()
{
UCOMIEnumMoniker classEnum = null;
UCOMIMoniker moniker = new UCOMIMoniker;
object source = null;
ICreateDevEnum devEnum = (ICreateDevEnum)(new CreateDevEnum());
int hr = devEnum.CreateClassEnumerator(FilterCategory.VideoInputDevice, out
classEnum, CDef.None);
DsError.ThrowExceptionForHR(hr);
Marshal.ReleaseComObject(devEnum);

if (classEnum == null)
{
throw new ApplicationException("No video capture device was
detected.\r\n\r\n" + "This sample requires a video capture device, such as
a USB WebCam,\r\nto be installed and working properly. The sample will now
close.");
}

int none = 0;

if (classEnum.Next(moniker.Length, moniker, out none) == 0)
{
Guid iid = typeof(IBaseFilter).GUID;
moniker.BindToObject(null, null, ref iid, out source);
}
else
{
throw new ApplicationException("Unable to access video capture device!");
}

Marshal.ReleaseComObject(moniker);
Marshal.ReleaseComObject(classEnum);

return (IBaseFilter)source;
}
The function posted above gives me the webcam I use for input. Then I want to
start previewing and save the file to harddisk by calling CaptureVideo()

private void CaptureVideo()
{
int hr = 0;
IBaseFilter sourceFilter = null;
try
{
sourceFilter = FindCaptureDevice();
this.graphBuilder = (IGraphBuilder)(new FilterGraph());
this.captureGraphBuilder = (ICaptureGraphBuilder2)(new
CaptureGraphBuilder2());
this.mediaControl = (IMediaControl)this.graphBuilder;
this.videoWindow = (IVideoWindow)this.graphBuilder;
this.mediaEventEx = (IMediaEventEx)this.graphBuilder;

graphBuilder.AddFilter((IBaseFilter)tee, "Tee");

IPin teeInput = DsFindPin.ByDirection((IBaseFilter)tee, PinDirection.Input,
0);
IPin vidOutput = DsFindPin.ByDirection(sourceFilter, PinDirection.Output, 0);

hr = graphBuilder.Connect(vidOutput, teeInput);
DsError.ThrowExceptionForHR(hr);

hr = this.mediaEventEx.SetNotifyWindow(this.Handle, WM_GRAPHNOTIFY,
IntPtr.Zero);

DsError.ThrowExceptionForHR(hr);
bool enregistrerLaVideo = false;
IPin teeOutput2 = DsFindPin.ByDirection((IBaseFilter)tee, PinDirection.Output,
0);
IBaseFilter MultiplexerF;
IFileSinkFilter FileSinkWriter;

string sFileName = "D:/result.avi";
hr = captureGraphBuilder.SetOutputFileName(MediaSubType.Avi, sFileName, out
MultiplexerF, out FileSinkWriter);
DsError.ThrowExceptionForHR(hr);

if (enregistrerLaVideo)
{
hr = captureGraphBuilder.RenderStream(null, MediaType.Video, teeOutput2, null,
MultiplexerF);
DsError.ThrowExceptionForHR(hr);
}

hr = this.captureGraphBuilder.SetFiltergraph(this.graphBuilder);
DsError.ThrowExceptionForHR(hr);

IVideoWindow videoWindow = captureGraphBuilder as IVideoWindow;
hr = videoWindow.put_Owner(this.Handle);
DsError.ThrowExceptionForHR(hr);

hr = videoWindow.put_WindowStyle(WindowStyle.Child |
WindowStyle.ClipChildren);
DsError.ThrowExceptionForHR(hr);

hr = videoWindow.put_Visible(OABool.True);
DsError.ThrowExceptionForHR(hr);
}
catch (Exception ex)
{
MessageBox.Show("An unrecoverable error has occurred.\r\n" + ex.ToString());
}
}

The problem is, that I get an exception with the code 0x8004025F when I want
the graphBuilder to connect teeInput with vidOutput.

Why?

Greetings,
Sebastian.

[Drew]

Have you looked at the DXWebCam sample? This shows how to do what you are
doing as well as a samplegrabber for the video.

[Sebastian-Nicolae Matei]

Hello,

I compiled that example right now, but do not get it running. If I enter
LOCALHOST as server name or the name of the computer hosting the webcam, I
get: "No connection possible. Connection was refused by target system."
(Translated from the german error message I get).

[Drew]

I think from memory that you need to run the server app from the exe and then
the client app from ide.

Though, isn't the samplegrabber capture part the main bit your after?

[Drew]

Sorry the other way around. just tested by compiling and running the server.
then running the client exe. I only put the ip address of my machine.

[Sebastian-Nicolae Matei]

If I try running the service by calling WebCamService.exe as admin I get the
error that the service cannot run and needs to be installed first. If I set
the WebCamService-2005 as startup project, it compiles and exits immediately.
Hmm...

[Drew]

The service is just that. it runs in the background and captures frames from
your webcam. the client just receives the packets and shows them as jpegs. Run
the service from your compile/run and the client from the exe.

[Sebastian-Nicolae Matei]

That's what I did, but like I said before, the compiler stops immediately
after having compiled the project and enters back to the development
environment.

[Drew]

Mmm.

Maybe try to add a breakpoint where it looks for your cam device. Might be
something there not finding your cam. If you add breakpoints all the way down
the buildgraph, you might see where it's falling over.

[Sebastian-Nicolae Matei]

I will try that. Are you sure I do not need to register it as a service if I
want to run it by calling the .exe?

[snarfle]

Sounds like a firewall problem? Also, try using the machine's actual IP
address instead of using localhost.