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Merged
hjmjohnson merged 4 commits into from
Apr 1, 2026
Merged

COMP: Migrate OpenCV Video Bridge from legacy C API to C++ API #5994

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3c255e8
COMP: Fix OpenCVBasicTypeBridge Matrix specialization for OpenCV 3/4
hjmjohnson Mar 31, 2026
fc98d0d
COMP: Migrate OpenCV Video IO from legacy C API to C++ API
hjmjohnson Mar 31, 2026
9cb4845
COMP: Replace legacy OpenCV C API in Video test files
hjmjohnson Mar 31, 2026
80a4883
BUG: Fix OpenWriter() to check isOpened() before setting m_WriterOpen
hjmjohnson Apr 1, 2026
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10 changes: 7 additions & 3 deletions Modules/Video/BridgeOpenCV/include/itkOpenCVBasicTypeBridge.h
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Original file line number Diff line number Diff line change
Expand Up @@ -161,10 +161,14 @@ struct OpenCVBasicTypeBridge<itk::Size<2>, cv::Size>
}
};

template <typename T, unsigned int VRows, unsigned int VColumns>
struct OpenCVBasicTypeBridge<itk::Matrix<T, VRows, VColumns>, cv::Matx<T, VRows, VColumns>>
// cv::Matx uses int template params; itk::Matrix uses unsigned int.
// Using int for VRows/VColumns (matching OpenCV) with a cast in the ITK
// pattern allows the compiler to deduce both sides correctly.
template <typename T, int VRows, int VColumns>
struct OpenCVBasicTypeBridge<itk::Matrix<T, static_cast<unsigned int>(VRows), static_cast<unsigned int>(VColumns)>,
cv::Matx<T, VRows, VColumns>>
{
using ITKDataType = itk::Matrix<T, VRows, VColumns>;
using ITKDataType = itk::Matrix<T, static_cast<unsigned int>(VRows), static_cast<unsigned int>(VColumns)>;
using OpenCVDataType = cv::Matx<T, VRows, VColumns>;

static ITKDataType
Expand Down
73 changes: 28 additions & 45 deletions Modules/Video/BridgeOpenCV/include/itkOpenCVVideoCapture.hxx
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Original file line number Diff line number Diff line change
Expand Up @@ -20,18 +20,8 @@

#include "itkNumericTraits.h"

#include "opencv2/core/version.hpp"
#if !defined(CV_VERSION_EPOCH) // OpenCV >= 3.0
# include "opencv2/videoio.hpp"
# include "opencv2/imgproc/types_c.h" // CV_RGB2BGR, CV_BGR2GRAY, ...
# include "opencv2/imgproc/imgproc_c.h"
# if CV_VERSION_MAJOR > 3 // OpenCV 4.x
# include "opencv2/videoio/legacy/constants_c.h"
# endif
#else
// OpenCV 2.4.x
# include "cv.h"
#endif
#include "opencv2/videoio.hpp"
#include "opencv2/imgproc.hpp"

namespace itk
{
Expand All @@ -50,7 +40,7 @@ OpenCVVideoCapture<TVideoStream>::OpenCVVideoCapture()
m_FpS = 24;

// Default to mp4.2
m_FourCC = CV_FOURCC('M', 'P', '4', '2');
m_FourCC = cv::VideoWriter::fourcc('M', 'P', '4', '2');
}

//
Expand All @@ -65,7 +55,7 @@ OpenCVVideoCapture<TVideoStream>::OpenCVVideoCapture(TVideoStream * videoStream)
m_FpS = 24;

// Default to mp4.2
m_FourCC = CV_FOURCC('M', 'P', '4', '2');
m_FourCC = cv::VideoWriter::fourcc('M', 'P', '4', '2');
}


Expand Down Expand Up @@ -121,7 +111,7 @@ OpenCVVideoCapture<TVideoStream>::grab()

// Move the current frame forward by 1
SizeValueType currentFrame = m_VideoStream->GetRequestedTemporalRegion().GetFrameStart();
return set(CV_CAP_PROP_POS_FRAMES, currentFrame + 1);
return set(cv::CAP_PROP_POS_FRAMES, currentFrame + 1);
}

//
Expand Down Expand Up @@ -162,35 +152,28 @@ OpenCVVideoCapture<TVideoStream>::retrieve(cv::Mat & image, int itkNotUsed(chann
unsigned int channels = itk::NumericTraits<PixelType>::MeasurementVectorType::Dimension;
int matrixType = CV_MAKETYPE(depth, channels);

// Copy the pixels -- There is probably a faster way to do this
// Copy the pixels using cv::Mat (no IplImage needed)

// Currently only support mono and RGB (unsigned) char pixels
IplImage * iplImg = cvCreateImage(cvSize(size[0], size[1]), IPL_DEPTH_8U, channels);
// cv::Mat(rows, cols, type, data): rows=height=size[1], cols=width=size[0]
cv::Mat srcMat(static_cast<int>(size[1]),
static_cast<int>(size[0]),
matrixType,
reinterpret_cast<char *>(frame->GetBufferPointer()));
if (matrixType == CV_8UC1 || matrixType == CV_8SC1)
{
// Insert the buffer into iplImg
cvSetData(iplImg, reinterpret_cast<char *>(frame->GetBufferPointer()), iplImg->widthStep);
srcMat.copyTo(image);
}
else if (matrixType == CV_8UC3 || matrixType == CV_8SC3)
{
// Place the contents of the buffer into an OpenCV image
IplImage * tempImg = cvCreateImage(cvSize(size[0], size[1]), IPL_DEPTH_8U, channels);

// Insert the buffer into tempImg
cvSetData(tempImg, reinterpret_cast<char *>(frame->GetBufferPointer()), tempImg->widthStep);

// Convert to BGR
cvCvtColor(tempImg, iplImg, CV_RGB2BGR);
// Convert ITK RGB to OpenCV BGR
cv::cvtColor(srcMat, image, cv::COLOR_RGB2BGR);
}
else
{
itkExceptionStringMacro("itk::OpenCVVideoCaptures -> Pixel type not supported");
}

// Pass off to the Mat
image.create(size[0], size[1], matrixType);
image = cv::cvarrToMat(iplImg, true);

// Return success
return true;
}
Expand Down Expand Up @@ -255,12 +238,12 @@ OpenCVVideoCapture<TVideoStream>::set(int propId, double value)
switch (propId)
{
// Figure out the frame numbers from the value -- This is not currently supported
case CV_CAP_PROP_POS_MSEC:
case cv::CAP_PROP_POS_MSEC:
itkExceptionStringMacro("OpenCVVideoCapture: Video Pipeline does not currently support RealTime");
break;

// Set the frame start of the requested region and update the pipeline
case CV_CAP_PROP_POS_FRAMES:
case cv::CAP_PROP_POS_FRAMES:

// Get the largest temporal region and make sure it has some duration
m_VideoStream->UpdateOutputInformation();
Expand Down Expand Up @@ -293,25 +276,25 @@ OpenCVVideoCapture<TVideoStream>::set(int propId, double value)
break;

// Figure out the frame number from the AVI ratio and set accordingly
case CV_CAP_PROP_POS_AVI_RATIO:
case cv::CAP_PROP_POS_AVI_RATIO:

// Compute the new frame
m_VideoStream->UpdateOutputInformation();
largestPossible = m_VideoStream->GetLargestPossibleTemporalRegion();
ratioFrameOffset = (SizeValueType)(static_cast<double>(largestPossible.GetFrameDuration()) * value);
newFrame = largestPossible.GetFrameStart() + ratioFrameOffset;

// Use the CV_CAP_PROP_POS_FRAMES property to update
set(CV_CAP_PROP_POS_FRAMES, newFrame);
// Use the cv::CAP_PROP_POS_FRAMES property to update
set(cv::CAP_PROP_POS_FRAMES, newFrame);
break;

// Set FourCC
case CV_CAP_PROP_FOURCC:
case cv::CAP_PROP_FOURCC:
m_FourCC = static_cast<int>(value);
break;

// Set FpS
case CV_CAP_PROP_FPS:
case cv::CAP_PROP_FPS:
m_FpS = value;
break;

Expand Down Expand Up @@ -347,16 +330,16 @@ OpenCVVideoCapture<TVideoStream>::get(int propId)
switch (propId)
{
// Figure out the frame numbers from the value -- This is not currently supported
case CV_CAP_PROP_POS_MSEC:
case cv::CAP_PROP_POS_MSEC:
itkExceptionStringMacro("OpenCVVideoCapture: Video Pipeline does not currently support RealTime");
break;

// Get the frame start of the requested region and update the pipeline
case CV_CAP_PROP_POS_FRAMES:
case cv::CAP_PROP_POS_FRAMES:
return frameNum;

// Figure out the frame number from the AVI ratio and set accordingly
case CV_CAP_PROP_POS_AVI_RATIO:
case cv::CAP_PROP_POS_AVI_RATIO:

// Compute the frame number from the ratio
m_VideoStream->UpdateOutputInformation();
Expand All @@ -366,20 +349,20 @@ OpenCVVideoCapture<TVideoStream>::get(int propId)
return static_cast<double>(currentOffset) / static_cast<double>(largest.GetFrameDuration());

// Get FourCC
case CV_CAP_PROP_FOURCC:
case cv::CAP_PROP_FOURCC:
return m_FourCC;

// Set FpS
case CV_CAP_PROP_FPS:
case cv::CAP_PROP_FPS:
return m_FpS;

// Get Frame Width
case CV_CAP_PROP_FRAME_WIDTH:
case cv::CAP_PROP_FRAME_WIDTH:
m_VideoStream->UpdateOutputInformation();
return m_VideoStream->GetFrameLargestPossibleSpatialRegion(frameNum).GetSize()[0];

// Get Frame Height
case CV_CAP_PROP_FRAME_HEIGHT:
case cv::CAP_PROP_FRAME_HEIGHT:
m_VideoStream->UpdateOutputInformation();
return m_VideoStream->GetFrameLargestPossibleSpatialRegion(frameNum).GetSize()[1];

Expand Down
22 changes: 5 additions & 17 deletions Modules/Video/BridgeOpenCV/include/itkOpenCVVideoIO.h
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Original file line number Diff line number Diff line change
Expand Up @@ -20,17 +20,7 @@

#include "itkVideoIOBase.h"

#include "opencv2/core/version.hpp"
#if !defined(CV_VERSION_EPOCH)
// OpenCV 3.x
# include "opencv2/videoio/videoio.hpp"
# include "opencv2/videoio/videoio_c.h"
# include "opencv2/imgproc/imgproc_c.h"
#else
// OpenCV 2.4.x
# include "cv.h"
# include "highgui.h"
#endif
#include "opencv2/videoio.hpp"

#include "ITKVideoBridgeOpenCVExport.h"

Expand Down Expand Up @@ -194,12 +184,10 @@ class ITKVideoBridgeOpenCV_EXPORT OpenCVVideoIO : public VideoIOBase
OpenWriter();

private:
private:
IplImage * m_CVImage{};
IplImage * m_TempImage{};
CvCapture * m_Capture{};
CvVideoWriter * m_Writer{};
int m_FourCC{};
cv::Mat m_CVImage{};
cv::VideoCapture m_Capture{};
cv::VideoWriter m_Writer{};
int m_FourCC{};

int m_CameraIndex{};
};
Expand Down
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