Emgucv(二)Emgucv和Aforge录制视频

一、Emgucv录制视频

　　Emgucv中的Capture类可以完成视频文件的读取，利用EmguCV播放视频的原理是：将视频看作图片，用capture获取抓取通道，通过不断的调用｛frame =
capture.QueryFrame();imageBox1.Image = frame;｝语句实现图像的实时显示。

　　录制视频时用到了VideoWriter()这个函数，它有两种构造方法，分别为VideoWriter(string fileName, int compressionCode, int fps, int width, int height, bool isColor)和VideoWriter(string fileName, int fps, int width, int height, bool isColor)，其中：

　　fileName：文件的保存路径；

　　compressionCode：视频的编码方式；

　　fps：录制视频的帧率；

　　width：视频的宽度；

　　height：视频的高度；

　　isColor：是否是彩色；

最后调用WriteFrame()方法录制视频

　　首先我们要做的第一步就是打开电脑自带的摄像头，其代码为:

 private Capture capture;
         private void btnStart_Click(object sender, EventArgs e)
         {
             capture = new Capture();
             Application.Idle += new EventHandler(processfram);
         }
         private void processfram(object sender, EventArgs arg)
         {
             frame = capture.QueryFrame();
             imageBox1.Image = frame;
         }

　　接下来再录制视频，其关键代码为：

 vw = new VideoWriter("E:\\1.avi", CvInvoke.CV_FOURCC('M', 'J', 'P', 'G'), ,(int)CvInvoke.cvGetCaptureProperty(capture, Emgu.CV.CvEnum.CAP_PROP.CV_CAP_PROP_FRAME_WIDTH), (int)CvInvoke.cvGetCaptureProperty(capture, Emgu.CV.CvEnum.CAP_PROP.CV_CAP_PROP_FRAME_HEIGHT), true);
                     Application.Idle += new EventHandler(processfram);

　　其完整代码为：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Windows.Forms;
 using Emgu.CV;
 using Emgu.CV.Structure;

 namespace test
 {
     public partial class Form1 : Form
     {
         public Form1()
         {
             InitializeComponent();
         }
         private Capture capture;
         Image<Bgr, Byte> frame;
         VideoWriter vw;
         bool flag = false;
         private void btnStart_Click(object sender, EventArgs e)
         {
             btnRecord.Enabled = true;
             capture = new Capture();
             Application.Idle += new EventHandler(processfram);
         }
         private void processfram(object sender, EventArgs arg)
         {
             frame = capture.QueryFrame();
             imageBox1.Image = frame;
             if(flag)
                 vw.WriteFrame(frame);
         }

         private void btnRecord_Click(object sender, EventArgs e)
         {
             if (btnRecord.Text == "录制")
             {
                 if (MessageBox.Show("开始录制吗？", "Information", MessageBoxButtons.OKCancel, MessageBoxIcon.Information) == DialogResult.OK)
                 {
                     flag = true;
                     vw = new VideoWriter("E:\\1.avi", CvInvoke.CV_FOURCC('M', 'J', 'P', 'G'), ,(int)CvInvoke.cvGetCaptureProperty(capture, Emgu.CV.CvEnum.CAP_PROP.CV_CAP_PROP_FRAME_WIDTH), (int)CvInvoke.cvGetCaptureProperty(capture, Emgu.CV.CvEnum.CAP_PROP.CV_CAP_PROP_FRAME_HEIGHT), true);
                     Application.Idle += new EventHandler(processfram);
                     btnRecord.Text = "暂停";
                 }
             }
             else
             {
                 if (MessageBox.Show("停止录制吗？", "Information", MessageBoxButtons.OKCancel, MessageBoxIcon.Information) == DialogResult.OK)
                 {
                     flag = false;
                     Application.Idle -= new EventHandler(processfram);
                     vw.Dispose();
                     btnRecord.Text = "录制";
                 }
             }
         }
     }
 }

二、Aforge录制视频(在上一篇博客的基础上，所以在此之前先看完上一篇博客)

　　Aforge录制视频调用的是AVIWriter()函数，所以在此之前先要引入AForge.Video.VFW.dll程序集，其具体步骤如下：

　　（1）先new一个AVIWriter对象，如AVIWriter writer = new AVIWriter("wmv3")，此代表的是录制的事avi格式的视频，但是必须先要装个插件，下载地址http://blog.csdn.net/wletv/article/details/9188417，唯一的缺点就是不能64位的系统下运行；如果不加“wmv3”则没有这个问题，可是录制几秒就有一两百兆了，十分的不可取（如果谁有更好的解决办法请及时告诉我哦:））；

　　（2）接着调用其Open方法，如writer.Open(string fileName, int width, int height)，其中fileName为路径，width为宽度，height为高度；

　　（3）写入视频文件，调用AddFrame方法；

完整代码为：

 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
 using System.Drawing;
 using System.Linq;
 using System.Text;
 using System.Windows.Forms;
 using AForge.Video.DirectShow;
 using AForge.Video;
 using System.Diagnostics;
 using AForge.Video.VFW;

 namespace Aforge调用摄像头
 {
     public partial class Form1 : Form
     {
         private FilterInfoCollection videoDevices;
         private VideoCaptureDevice videoSource;
         AVIWriter writer = new AVIWriter();
         private Bitmap bitmap,img;
         public Form1()
         {
             InitializeComponent();
         }

         private void Form1_Load(object sender, EventArgs e)
         {
             try
             {
                 videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);//枚举所有的视频输入设备
                 if (videoDevices.Count == )
                     throw new ApplicationException();
                 foreach (FilterInfo device in videoDevices)
                 {
                     cbCapture.Items.Add(device.Name);//把所有的视频设备添加到下拉框中
                 }
                 cbCapture.SelectedIndex = ;
                 videoSource = new VideoCaptureDevice(videoDevices[cbCapture.SelectedIndex].MonikerString);//摄像头的名称
                 videoSource.DesiredFrameSize = new Size(, );//设置大小
                 videoSource.DesiredFrameRate = ;//设置帧率
                 videoSource.NewFrame += new NewFrameEventHandler(video_NewFrame);
                 videoSource.Start();
             }
             catch (Exception ex)
             {
                 MessageBox.Show(ex.Message);
             }
         }
         private void btnStart_Click(object sender, EventArgs e)
         {
             videoSource.Stop();
             videoSource = new VideoCaptureDevice(videoDevices[cbCapture.SelectedIndex].MonikerString);//摄像头的名称
             videoSource.DesiredFrameSize = new Size(, );//设置大小
             videoSource.DesiredFrameRate = ;//设置帧率
             videoSource.NewFrame += new NewFrameEventHandler(video_NewFrame);
             videoSource.Start();
         }
         private void video_NewFrame(object sender, NewFrameEventArgs eventArgs)
         {
             bitmap = (Bitmap)eventArgs.Frame.Clone();
             pictureBox1.Image = bitmap;
         }

         private void btnConfig_Click(object sender, EventArgs e)
         {
             if ((videoSource != null) && (videoSource is VideoCaptureDevice))
             {
                 try
                 {
                     ((VideoCaptureDevice)videoSource).DisplayPropertyPage(this.Handle);
                 }
                 catch (NotSupportedException ex)
                 {
                     MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                 }
             }
         }

         private void Form1_FormClosing(object sender, FormClosingEventArgs e)
         {
             Process p = Process.GetCurrentProcess();
             if (p.HasExited == false)
             {
                 p.Kill();
             }
         }
         private void btnRecord_Click(object sender, EventArgs e)
         {
             if (btnRecord.Text == "录制")
             {
                 if (MessageBox.Show("Start Recording?", "Information", MessageBoxButtons.OKCancel, MessageBoxIcon.Information) == DialogResult.OK)
                 {
                     writer = new AVIWriter("wmv3");
                     writer.Open("E:\\1.avi", bitmap.Width, bitmap.Height);
                     videoSource.NewFrame += new NewFrameEventHandler(video_NewFrames);
                     btnRecord.Text = "停止";
                 }
             }
             else
             {
                 if (MessageBox.Show("Stop Recording?", "Information", MessageBoxButtons.OKCancel, MessageBoxIcon.Information) == DialogResult.OK)
                 {
                     writer.Dispose();//不dispose掉会报错，不能是close
                     btnRecord.Text = "录制";
                 }
             }
         }
         private void video_NewFrames(object sender, NewFrameEventArgs eventArgs)
         {
             img = (Bitmap)eventArgs.Frame.Clone();
             writer.AddFrame(img);
         }
     }
 }