Question

i am recording video from webcam using DirectshowLib2005.dll in C#.net..i have this code to startVideoRecoding as below..

try
        {
            IBaseFilter capFilter = null;
            IBaseFilter asfWriter = null;
            IFileSinkFilter pTmpSink = null;
            ICaptureGraphBuilder2 captureGraph = null;
            GetVideoDevice();
            if (availableVideoInputDevices.Count > 0)
            {
                //
                //init capture graph
                //
                graphBuilder = (IFilterGraph2)new FilterGraph();
                captureGraph = (ICaptureGraphBuilder2)new CaptureGraphBuilder2();
                //
                //sets filter object from graph
                //
                captureGraph.SetFiltergraph(graphBuilder);
                //
                //which device will use graph setting
                //
                graphBuilder.AddSourceFilterForMoniker(AvailableVideoInputDevices.First().Mon, null, AvailableVideoInputDevices.First().Name, out capFilter);
                captureDeviceName = AvailableVideoInputDevices.First().Name;
                //
                //check saving path is exsist or not;if not then create
                //
                if (!Directory.Exists(ConstantHelper.RootDirectoryName + "\\Assets\\Video\\"))
                {
                    Directory.CreateDirectory(ConstantHelper.RootDirectoryName + "\\Assets\\Video\\");
                }
                #region WMV                   
                //
                //sets output file name,and file type
                //
                captureGraph.SetOutputFileName(MediaSubType.Asf, ConstantHelper.RootDirectoryName + "\\Assets\\Video\\" + videoFilename + ".wmv", out asfWriter, out pTmpSink);                    
                //
                //configure which video setting is used by graph
                //                
                IConfigAsfWriter lConfig = asfWriter as IConfigAsfWriter;
                Guid asfFilter = new Guid("8C45B4C7-4AEB-4f78-A5EC-88420B9DADEF");
                lConfig.ConfigureFilterUsingProfileGuid(asfFilter);
                #endregion
                //
                //render the stram to output file using graph setting
                //
                captureGraph.RenderStream(null, null, capFilter, null, asfWriter);
                m_mediaCtrl = graphBuilder as IMediaControl;
                m_mediaCtrl.Run();
                isVideoRecordingStarted = true;
                VideoStarted(m_mediaCtrl, null);
            }
            else
            {
                isVideoRecordingStarted = false;
            }
        }
        catch (Exception Ex)
        {               
           ErrorLogging.WriteErrorLog(Ex);
        }

if you observe this lines of code

//
                //configure which video setting is used by graph
                //                
                IConfigAsfWriter lConfig = asfWriter as IConfigAsfWriter;
                Guid asfFilter = new Guid("8C45B4C7-4AEB-4f78-A5EC-88420B9DADEF");
                lConfig.ConfigureFilterUsingProfileGuid(asfFilter);

it will apply video setting which is described on that GUID i got this GUID from file located at “C:\windows\WMSysPr9.prx”..

so my question is how create my own video setting with format,resolutions and all?

How to Record video using webcam in black and white mode or in grayscale?

Answer 1

so my question is how create my own video setting with format,resolutions and all?

GUID based profiles are deprecated, though you can still use them. You can build custom profile in code using WMCreateProfileManager and friends (you start with empty profile and add video and/or audio streams at your discretion). This is C++ API, and I suppose that WindowsMedia.NET, a sister project to DirectShowLib you are already using, provides you interface into .NET code.

Windows SDK WMGenProfile sample both shows how to build profile manually and provides you a tool to build it interactively and save into .PRX file you can use in your application.

$(WindowsSDK)\Samples\multimedia\windowsmediaformat\wmgenprofile

How to Record video using webcam in black and white mode or in grayscale?

The camera gives you a picture, then it goes through pipeline up to recording through certain processing. Ability to make it greyscale is not something inherent.

There are two things you might want to think of. First of all, if the camera is capable of stripping color information on capture, you can leverage this. Check it out – if its settings have Saturation slider, then you just put it input minimal value position and the camera gives you greyscale.

In code, you use IAMVideoProcAmp interface for this.

Another option, including if the camera is missing mentioned capability, is to apply post processing filter or effect that converts to greyscale. There is no stock solution for this, and otherwise there are several ways to achieve the effect:

• use third party filter that strips color
• export from DirectShow pipeline, convert data in code using Color Control Transform DSP (available starting Win Vista) or GDI functions
• use Sample Grabber in the streaming pipeline and update image bits directly