[vtkusers] capturing video

[Mark E Roberts]

Narjes,

For a project that I am working on, I have some video coming in through an S-video cable. I sent out an e-mail to the mailing group and got a response back from David Gobbi, who gave me some example code in TCL. I changed it to C++ and have included it below.

I've also included the CMakeFile that I use below the code. Watch out for the file that you are going to use and change it if necessary in the ADD_EXECUTABLE. 

I believe you also have to turn on VTK_USE_VIDEO_FOR_WINDOWS when compiling VTK with CMAKE. So, if you didn't turn that on when compiling VTK, you are going to need to go back and fix that. 

If you have any questions, please feel free to e-mail me back.

Mark Roberts

/******************************
Example Code
******************************/

// First include the required header files for the VTK classes we are using.

#include <stdlib.h>
#include "vtkRenderWindowInteractor.h"
#include "vtkWin32VideoSource.h"
#include "vtkImageViewer.h"
#include "vtkCallbackCommand.h"
#include "vtkCommand.h"

vtkWin32VideoSource *grabber = NULL;
vtkImageViewer *viewer = NULL;
vtkRenderWindowInteractor *iren = NULL;

class vtkMyCallback : public vtkCommand
{
public:
	static vtkMyCallback *New()
	{return new vtkMyCallback;}
	virtual void Execute(vtkObject *caller, unsigned long, void*)
	{
		//re-grab and image and render		
		grabber->Grab();
		viewer->Render();
				
		//update the timer so it will trigger again
		//VTKI_TIMER_UPDATE = 1
		iren->CreateTimer(VTKI_TIMER_UPDATE);
}
};

int main()
{	
	
	//Add the video source here
	grabber = vtkWin32VideoSource::New();
	grabber->SetFrameSize(740, 480, 1);
	grabber->VideoSourceDialog();
	grabber->VideoFormatDialog();
	grabber->Grab();				//grab a single frame from the video

	viewer = vtkImageViewer::New();
	viewer->SetInput(grabber->GetOutput());   //set image to the render and window
	viewer->SetColorWindow(255);
	viewer->SetColorLevel(127.5);
	viewer->SetZSlice(0);
	
	//Create the interactor that handles the event loop
	iren = vtkRenderWindowInteractor::New();
	iren->SetRenderWindow(viewer->GetRenderWindow());
	viewer->SetupInteractor(iren);

	viewer->Render();	//must be called after iren and viewer are linked
	//or there will be problems
	
	//establish timer event and create timer
	vtkMyCallback *call = vtkMyCallback::New();
	iren->AddObserver(vtkCommand::TimerEvent, call);
	iren->CreateTimer(VTKI_TIMER_FIRST);		//VTKI_TIMER_FIRST = 0

	//iren must be initialized so that it can handle events
	iren->Initialize();
	iren->Start();
	
	//delete all instances and release the hold the win32videosource
	//has on the pci card
	grabber->ReleaseSystemResources();
	grabber->Delete();
	viewer->Delete();
	iren->Delete();

}

/************************
CMakeFile
************************/
PROJECT (Step1)

FIND_PACKAGE(VTK REQUIRED)
IF(NOT VTK_USE_RENDERING)
  MESSAGE(FATAL_ERROR "Example ${PROJECT_NAME} requires VTK_USE_RENDERING.")
ENDIF(NOT VTK_USE_RENDERING)
INCLUDE(${VTK_USE_FILE})

# Check if vfw32 supports the video capture functions
  IF(VTK_USE_VIDEO_FOR_WINDOWS)
    IF("VTK_VFW_SUPPORTS_CAPTURE" MATCHES "^VTK_VFW_SUPPORTS_CAPTURE$")
      MESSAGE(STATUS "Checking if vfw32 supports video capture")
      TRY_COMPILE(VTK_VFW_SUPPORTS_CAPTURE
        ${VTK_BINARY_DIR}/CMakeTmp
        ${VTK_CMAKE_DIR}/vtkTestvfw32Capture.cxx
        CMAKE_FLAGS "-DLINK_LIBRARIES:STRING=vfw32"
        OUTPUT_VARIABLE OUTPUT)
      IF(VTK_VFW_SUPPORTS_CAPTURE)
        MESSAGE(STATUS "Checking if vfw32 supports video capture -- yes")
        SET(VTK_VFW_SUPPORTS_CAPTURE 1 CACHE INTERNAL "Enable using Video for Windows (vfw32) for video capture.")
        WRITE_FILE(${CMAKE_BINARY_DIR}/CMakeFiles/CMakeOutput.log
          "Checking if vfw32 supports video capture "
          "passed with the following output:\n"
          "${OUTPUT}\n" APPEND)
      ELSE(VTK_VFW_SUPPORTS_CAPTURE)
        MESSAGE(STATUS "Checking if vfw32 supports video capture -- no")
        SET(VTK_VFW_SUPPORTS_CAPTURE 0 CACHE INTERNAL "Enable using Video for Windows (vfw32) for video capture.")
        WRITE_FILE(${CMAKE_BINARY_DIR}/CMakeFiles/CMakeOutput.log
          "Checking if vfw32 supports video capture "
          "failed with the following output:\n"
          "${OUTPUT}\n" APPEND)
      ENDIF(VTK_VFW_SUPPORTS_CAPTURE)
    ENDIF("VTK_VFW_SUPPORTS_CAPTURE" MATCHES "^VTK_VFW_SUPPORTS_CAPTURE$")
  ELSE(VTK_USE_VIDEO_FOR_WINDOWS)
    SET(VTK_VFW_SUPPORTS_CAPTURE 0)
  ENDIF(VTK_USE_VIDEO_FOR_WINDOWS)
ENDIF(VTK_USE_RENDERING AND WIN32)

ADD_EXECUTABLE(Cone Win32c.cxx)
TARGET_LINK_LIBRARIES(Cone vtkRendering vtkHybrid)

/********************************************
End of .cxx code and CMAKE
********************************************/


> Hey VTK
> 
> I have a real time video and i want to capture and save it . But i'm a new
> user of VTK with zero experience, so unfortunately i have no idea where
> to start from. Any help would be really appreciated
> 
> Thanx in advance narjes
> 
> 
> --------------------------------- Be a better sports nut! Let your teams
> follow you with Yahoo Mobile. Try it now.


-- 
Mark Roberts
Masters of Science, Project Student
CER Lab
Carnegie Mellon University

301-806-6529

MRoberts at andrew.cmu.edu
MeerkyJ at gmail.com