jrpharis's profile - activity

I am using the sample code video-write.cpp(included below for convenience) to learn how to use videos with OpenCV.

#include <iostream> // for standard I/O
#include <string>   // for strings

#include <opencv2 core="" core.hpp="">        // Basic OpenCV structures (cv::Mat)
#include <opencv2 highgui="" highgui.hpp="">  // Video write

using namespace std;
using namespace cv;

static void help()
{
    cout
        << "------------------------------------------------------------------------------" << endl
        << "This program shows how to write video files."                                   << endl
        << "You can extract the R or G or B color channel of the input video."              << endl
        << "Usage:"                                                                         << endl
        << "./video-write inputvideoName [ R | G | B] [Y | N]"                              << endl
        << "------------------------------------------------------------------------------" << endl
        << endl;
}

int main(int argc, char *argv[])
{
    help();

    if (argc != 4)
    {
        cout << "Not enough parameters" << endl;
        return -1;
    }

    const string source      = argv[1];           // the source file name
    const bool askOutputType = argv[3][0] =='Y';  // If false it will use the inputs codec type

    VideoCapture inputVideo(source);              // Open input
    if (!inputVideo.isOpened())
    {
        cout  << "Could not open the input video: " << source << endl;
        return -1;
    }

    string::size_type pAt = source.find_last_of('.');                  // Find extension point
    const string NAME = source.substr(0, pAt) + argv[2][0] + ".avi";   // Form the new name with container
    int ex = static_cast<int>(inputVideo.get(CV_CAP_PROP_FOURCC));     // Get Codec Type- Int form

    // Transform from int to char via Bitwise operators
    char EXT[] = {(char)(ex & 0XFF) , (char)((ex & 0XFF00) >> 8),(char)((ex & 0XFF0000) >> 16),(char)((ex & 0XFF000000) >> 24), 0};

    Size S = Size((int) inputVideo.get(CV_CAP_PROP_FRAME_WIDTH),    // Acquire input size
                  (int) inputVideo.get(CV_CAP_PROP_FRAME_HEIGHT));

    VideoWriter outputVideo;                                        // Open the output
    if (askOutputType)
        outputVideo.open(NAME, ex=-1, inputVideo.get(CV_CAP_PROP_FPS), S, true);
    else
        outputVideo.open(NAME, ex, inputVideo.get(CV_CAP_PROP_FPS), S, true);

    if (!outputVideo.isOpened())
    {
        cout  << "Could not open the output video for write: " << source << endl;
        return -1;
    }

    cout << "Input frame resolution: Width=" << S.width << "  Height=" << S.height
         << " of nr#: " << inputVideo.get(CV_CAP_PROP_FRAME_COUNT) << endl;
    cout << "Input codec type: " << EXT << endl;

    int channel = 2; // Select the channel to save
    switch(argv[2][0])
    {
    case 'R' : channel = 2; break;
    case 'G' : channel = 1; break;
    case 'B' : channel = 0; break;
    }
    Mat src, res;
    vector<mat> spl;

    for(;;) //Show the image captured in the window and repeat
    {
        inputVideo >> src;              // read
        if (src.empty()) break;         // check if at end

        split(src, spl);                // process - extract only the correct channel
        for (int i =0; i < 3; ++i)
            if (i != channel)
                spl[i] = Mat::zeros(S, spl[0].type());
       merge(spl, res);

       //outputVideo.write(res); //save or
       outputVideo << res;
    }

    cout << "Finished writing" << endl;
    return 0;
}

However, once the program starts to write to the output file, 3 lines from the bottom of the code, I get the error below. I get the same error using either output method, and if I try to just put the src straight back to the output(outputVideo << src).

I found another sample program(http://opencv.willowgarage.com/wiki/documentation/cpp/highgui/VideoWriter) that opens the default camera(my built-in webcam), it is able to output just fine. This code is below.

    
    #include "opencv\cv.h"
#include "opencv\highgui.h"

using namespace cv;

int main(int, char**)
{
    VideoCapture capture(1); // open the default camera

    if ...

I am having trouble passing IplImage* parameters in functions. This is for a school project and unfortunately am not supposed to edit the files doing the calling to my filter functions. In the main, the image is brought in as a command line parameter, then a copy of this is made and passed to the correct filter function, as such:

IplImage * floating = cvCreateImage (cvSize (img->width, img->height), IPL_DEPTH_32F, 3);
cvConvertScale (img, floating, 1/255., 0);

IplImage * filtered;

switch (filter.ImageFormat)
{
  case YUV24:
    filtered = cvCreateImage (cvSize (floating->width, floating->height), IPL_DEPTH_32F, 3);
    cvCvtColor (floating, filtered, CV_BGR2YCrCb);
    break;
  case BGR24:
    filtered = cvCloneImage (floating);
    break;
  case Gray:
    filtered = cvCreateImage (cvSize (floating->width, floating->height), IPL_DEPTH_32F, 1);
    cvCvtColor (floating, filtered, CV_BGR2GRAY);
    break;
}

cvNamedWindow ("original", CV_WINDOW_AUTOSIZE);
cvShowImage ("original", img);

filter.ImageFilter (filtered, p);

if (filter.ImageFormat == YUV24)
{
  cvCvtColor (filtered, filtered, CV_YCrCb2BGR);
}

cvNamedWindow (filterName.c_str(), CV_WINDOW_AUTOSIZE);
cvShowImage (filterName.c_str(), filtered);

And here is the code from one of my filters:

void median (IplImage * image, int k){
  Mat matImage(image);        //convert IplImage to Mat for work
  vector<Mat> bgr_channels;   //vector to hold each channel
  int i,j,m,n;                //row/column indeces
  int kernelSize = (2*k+1)*(2*k+1);
  vector<float> vals(kernelSize); //kernelSized vector to hold all values of image
                                  //within kernel centered at a given pixel
  int vecIndex = 0;   //then sorted to get the median
  int chanIndex = 0;  //index used to for each channel

  //add padding to account for border issues with convolution
  copyMakeBorder( matImage, matImage, k, k, k, k, BORDER_REPLICATE);
  //split channes to do work on individual channels
  split(matImage, bgr_channels);

  for(chanIndex=0; chanIndex < matImage.channels(); chanIndex++){
    //outer loop for scanning entire image
    for(i=k; i<matImage.rows-k; i++)/*image row index*/{
      for(j=k; j<matImage.cols-k; j++)/*image column index*/{
        //inner loop for scanning image only in kernel boundaries
        vecIndex = 0;   //reset vecIndex at start of each kernel loop
        for(m=i-k; m<(i+k+1); m++)/*kernel row index*/{
          for(n=j-k; n<(j+k+1); n++)/*kernel column index*/{                      
            vals[vecIndex++] = bgr_channels[chanIndex].at<float>(m,n);
          }
        }
        insertionSort(vals, 0, vals.size()-1);
        bgr_channels[chanIndex].at<float>(i,j) = vals[vals.size()/2]; 
          //new value chosen from middle element of sorted vector
      }
    }
  }

  merge(bgr_channels, matImage);      //merge channels together
  imshow("Median: Mat", matImage);    //left this in because the original doesn't get modified                                
                                      //when converting the Mat back to an IplImage 
  image = cvCloneImage(&(IplImage)matImage);  //convert backto IplImage for DesktopMain
}

The problem is, that the filtered image shown in the main, does not reflect the actual image. It only shows the original image. When I output put the Mat style image matImage in my filter function, it shows the filtered image. Immediately after I convert back to IplImage and set the IplImage* input parameter equal to the the converted, filtered version. But the changes do not reflect the image displayed in the main function.

This is making it hard to create some of my other filters such as Gaussian and Sobel, because those filters themselves make calls ... (more)