#dotnet – Display a video file🎥 in Winform using #OpenCV and #net5

2023-01-16T02:06:19-05:00

hello Sir

I hope you are well. I am new to openCvSharp. I am facing a problem from past couple of days and the problem is i am able to capture a video from device but absolutely no video from file may it be a mp4 or a sdp.
using
OpenCvSharp 4.6 version
OpenCvSharp.runtime.win 4.6

I have installed latest OpenCV 4.7 on my System my OS is windows. I have added its path to bin folder path to my system and Enviromental variables.

visual studio 2019. i am sharing my code,

namespace cvsharpwebcam
{
public partial class Form1 : Form
{
VideoCapture capture;
Mat frame;
Bitmap image;
public string _videoFile = “d:\video.mp4”;
public Form1()
{
InitializeComponent();
frame = new Mat();

        capture = new VideoCapture();


        //capture.Open("d://srtp.sdp", VideoCaptureAPIs.FFMPEG);
        capture.Open(_videoFile, VideoCaptureAPIs.ANY);

        if (!capture.IsOpened())
        {
            MessageBox.Show(" not capturing");
        }
    }

    public delegate void delegateShow(Bitmap b);

    private void SetPicture(Bitmap img)
    {
        //try
        //{
            if (pictureBox1.InvokeRequired)
            {
                pictureBox1.Invoke(new MethodInvoker(
                delegate ()
                {
                    pictureBox1.Image = img;
                }));
            }
            else
            {
                pictureBox1.Image = img;
            }
        //}
        //catch(Exception ex)
        //{
        //    ;
        //}
    }


    private void button1_Click(object sender, EventArgs e)
    {

        Thread t = new Thread(new ParameterizedThreadStart(ShowVideo));
        t.Start("");



    }

    private void ShowVideo(object ob)
    {
        while (true)
        {
            if (capture.IsOpened())
            {
                capture.Read(frame);
                image = BitmapConverter.ToBitmap(frame);
                if (pictureBox1.Image != null)
                {
                    pictureBox1.Image.Dispose();
                }

                SetPicture(image);

                //pictureBox1.Image = image;
            }
        }

    }
}

}

Above is my whole code which works fine for my videocapture from webcam but not from file.

can you kindly guide me what I am doing wrong. Why videocapture is not working for files. I am clueless . please please any help will be greatly appreciated.
i will be truly grateful.

Best Regards,
Sarah

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	using System;
	using System.Threading;
	using System.Windows.Forms;
	using OpenCvSharp;
	using OpenCvSharp.Extensions;
	using Size = OpenCvSharp.Size;

	namespace Demo13_WinFormVideoFromFile
	{
	public partial class Form1 : Form
	{
	private bool _run = false;
	private VideoCapture _capture;
	private Mat _image;
	private Thread _cameraThread;
	private string _videoFile = "4K camera example for Traffic Monitoring (Road).mp4";

	private delegate void SafeCallDelegate(string text);

	public Form1()
	{
	InitializeComponent();
	Load += Form1_Load;
	Closed += Form1_Closed;
	}

	private void Form1_Closed(object sender, EventArgs e)
	{
	_cameraThread.Interrupt();
	_capture.Release();
	}

	private void btnStart_Click(object sender, EventArgs e)
	{
	_capture = new VideoCapture(_videoFile);
	_run = true;
	}

	private void btnStop_Click(object sender, EventArgs e)
	{
	_run = false;
	}

	private void Form1_Load(object sender, EventArgs e)
	{
	_image = new Mat();
	_cameraThread = new Thread(new ThreadStart(CaptureCameraCallback));
	_cameraThread.Start();
	}

	private void CaptureCameraCallback()
	{
	while (true)
	{
	if (!_run) continue;
	var startTime = DateTime.Now;

	_capture.Read(_image);
	if (_image.Empty()) return;
	var imageRes = new Mat();
	Cv2.Resize(_image, imageRes, new Size(320, 240));

	var bmpWebCam = BitmapConverter.ToBitmap(imageRes);
	pictureBoxWebCam.Image = bmpWebCam;
	}
	}
	}
	}

#dotnet – Display a video file🎥 in Winform using #OpenCV and #net5

How to open and process a video frame by frame

References

Net 5 and OpenCV

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How to open and process a video frame by frame

References

Net 5 and OpenCV

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