how to disconnect from the webcame using directshow

Question

4.00/5 (1 vote)

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hello everyone,

I'm using DirectShow.net to capture images from a webCame,after searching the web I got this code and it works fine:

to see the original full code kindly follow the link below

bool SetupGraph()
       {
           int hr;
           try
           {
               hr = capGraph.SetFiltergraph(graphBuilder);
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               hr = graphBuilder.AddFilter(capFilter, "Ds.NET Video Capture Device");
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               DsUtils.ShowCapPinDialog(capGraph, capFilter, this.Handle);

               AMMediaType media = new AMMediaType();
               media.majorType = MediaType.Video;
               media.subType = MediaSubType.RGB24;
               media.formatType = FormatType.VideoInfo;        // ???
               hr = sampGrabber.SetMediaType(media);
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               hr = graphBuilder.AddFilter(baseGrabFlt, "Ds.NET Grabber");
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               Guid cat = PinCategory.Preview;
               Guid med = MediaType.Video;
               hr = capGraph.RenderStream(ref cat, ref med, capFilter, null, null); // baseGrabFlt
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               cat = PinCategory.Capture;
               med = MediaType.Video;
               hr = capGraph.RenderStream(ref cat, ref med, capFilter, null, baseGrabFlt); // baseGrabFlt
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               media = new AMMediaType();
               hr = sampGrabber.GetConnectedMediaType(media);
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);
               if ((media.formatType != FormatType.VideoInfo) || (media.formatPtr == IntPtr.Zero))
                   throw new NotSupportedException("صيغه غير معروفه");

               videoInfoHeader = (VideoInfoHeader)Marshal.PtrToStructure(media.formatPtr, typeof(VideoInfoHeader));
               Marshal.FreeCoTaskMem(media.formatPtr); media.formatPtr = IntPtr.Zero;

               hr = sampGrabber.SetBufferSamples(false);
               if (hr == 0)
                   hr = sampGrabber.SetOneShot(false);
               if (hr == 0)
                   hr = sampGrabber.SetCallback(null, 0);
               if (hr < 0)
                   Marshal.ThrowExceptionForHR(hr);

               return true;
           }
           catch (Exception ee)
           {
               MessageBox.Show(this, "Could not setup graph\r\n" + ee.Message, "DirectShow.NET", MessageBoxButtons.OK, MessageBoxIcon.Stop);
               return false;
           }
       }

my problem is when I call this form from another form for a second time it gives me this error: "Value does not fall within the expected range" when the compiler comes to this section:
hr = capGraph.RenderStream(ref cat, ref med, capFilter, null, null);

actually i discovered that the problem disappear when I unplug the web-came physically and plug it again, so I concluded that i need to unplug it using code
so please if u know tell me how to do it or if u have any better idea please tell me

you can access the original code on
http://www.codeproject.com/script/Content/ViewAssociatedFile.aspx?rzp=%2FKB%2Fdotnet%2FROTEsys%2Frotesys_src.zip&zep=Tracking.cs&obid=9401&obtid=2&ovid=1[^]

thank you for ur time and patience

Posted 6-Apr-11 15:27pm

tofa111

Updated 6-Apr-11 15:58pm

v2

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Comments

walterhevedeich 6-Apr-11 21:40pm

This is a long post. Only few will have the patience to view this question. Update your post to contain only the relevant parts.

tofa111 6-Apr-11 22:06pm

i modified it thank you

4 solutions

Solution 1

I having exactly same problem,
I am still researching, will post the solution once i find it

Posted 16-May-11 17:46pm

asaab

Comments

tofa111 17-May-11 1:10am

you don't need to do this, there is a better library I found.
here the link:

http://sites.google.com/site/webcamlibrarydotnet/winfrom-and-csharp-sample-code-and-download[^]

you just need to download the files in the bottom of the page then add the DLL to your solution and see the example in the other file to know how to use, believe me it's the easiest library I found
good luck

Solution 2

you don't need to do this, there is a better library I found.
here the link:

http://sites.google.com/site/webcamlibrarydotnet/winfrom-and-csharp-sample-code-and-download[^]

you just need to download the files in the bottom of the page then add the DLL to your solution and see the example in the other file to know how to use, believe me it's the easiest library I found
good luck

Posted 16-May-11 19:09pm

tofa111

Solution 3

that's pretty simple and easy to use.
unfortunately, I am stuck with DirectShow,
I can use the webcam component for the second viewer, but the main viewer has to use DS.

Posted 17-May-11 5:17am

asaab

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lucindom · Accepted Answer · 2015-03-06T07:44:00

In CloseInterfases method, add the next Lines:

C#

if (graphBuilder != null)
 {
     graphBuilder.RemoveFilter(capFilter);
 }
 baseGrabFlt = null;
 if (sampGrabber != null)
     Marshal.ReleaseComObject(sampGrabber); sampGrabber = null;

 if (capGraph != null)
     Marshal.ReleaseComObject(capGraph); capGraph = null;

 if (graphBuilder != null)
     Marshal.ReleaseComObject(graphBuilder); graphBuilder = null;

 if (capFilter != null)
     Marshal.ReleaseComObject(capFilter); capFilter = null;

 if (capDevices != null)
 {
     foreach (DsDevice d in capDevices)
         d.Dispose();
     capDevices = null;
 }