WPF 展示视频修改为WriteableBitmap
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接着上一篇,进行WriteableBitmap性能优化
修改后运行对比如下:
前(CPU与内存不稳定):
后:
使用NuGet如下:
01
—
代码如下
一、创建MainWindow.xaml代码如下。
<ws:Window x:Class="OpenCVSharpExample.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:ws="https://github.com/WPFDevelopersOrg.WPFDevelopers.Minimal"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:OpenCVSharpExample"
Icon="OpenCV_Logo.png"
mc:Ignorable="d" WindowStartupLocation="CenterScreen"
Title="OpenCVSharpExample https://github.com/WPFDevelopersOrg" Height="450" Width="800">
<Grid Margin="4">
<Grid.ColumnDefinitions>
<ColumnDefinition/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Image Grid.Row="0" Name="imgViewport"/>
<GroupBox Header="Operation" Grid.Column="1" Margin="0,0,4,0">
<Grid>
<Grid.RowDefinitions>
<RowDefinition/>
<RowDefinition/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<StackPanel Grid.Row="0" HorizontalAlignment="Center">
<CheckBox IsChecked="Binding IsSave,RelativeSource=RelativeSource AncestorType=local:MainWindow"
VerticalAlignment="Center" Content="Save" Margin="0,4"/>
<ComboBox Name="ComboBoxCamera" ItemsSource="Binding CameraArray,RelativeSource=RelativeSource AncestorType=local:MainWindow"
SelectedIndex="Binding CameraIndex,RelativeSource=RelativeSource AncestorType=local:MainWindow"
SelectionChanged="ComboBoxCamera_SelectionChanged"/>
</StackPanel>
<StackPanel Orientation="Horizontal" Grid.Row="2" HorizontalAlignment="Center">
<Button Name="btPlay" Content="Play" Style="StaticResource PrimaryButton" Click="btPlay_Click" IsEnabled="False"/>
<Button Name="btStop" Click="btStop_Click" Content="Stop" Margin="4,0"/>
</StackPanel>
</Grid>
</GroupBox>
</Grid>
</ws:Window>
二、MainWindow.xaml.cs代码如下。
using OpenCvSharp;
using OpenCvSharp.Extensions;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Management;
using System.Threading;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media.Imaging;
using System.Windows.Threading;
namespace OpenCVSharpExample
/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow
private VideoCapture capCamera;
private VideoWriter videoWriter;
private Mat matImage = new Mat();
private Thread cameraThread;
private Thread writerThread;
private CascadeClassifier haarCascade;
private WriteableBitmap writeableBitmap;
private Rectangle rectangle;
public List<string> CameraArray
get return (List<string>)GetValue(CameraArrayProperty);
set SetValue(CameraArrayProperty, value);
public static readonly DependencyProperty CameraArrayProperty =
DependencyProperty.Register("CameraArray", typeof(List<string>), typeof(MainWindow), new PropertyMetadata(null));
public int CameraIndex
get return (int)GetValue(CameraIndexProperty);
set SetValue(CameraIndexProperty, value);
public static readonly DependencyProperty CameraIndexProperty =
DependencyProperty.Register("CameraIndex", typeof(int), typeof(MainWindow), new PropertyMetadata(0));
public bool IsSave
get return (bool)GetValue(IsSaveProperty);
set SetValue(IsSaveProperty, value);
public static readonly DependencyProperty IsSaveProperty =
DependencyProperty.Register("IsSave", typeof(bool), typeof(MainWindow), new UIPropertyMetadata(IsSaveChanged));
private static void IsSaveChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
var mainWindow = d as MainWindow;
if (e.NewValue != null)
var save = (bool) e.NewValue;
if (save)
mainWindow.StartRecording();
else
mainWindow.StopRecording();
public MainWindow()
InitializeComponent();
Width = SystemParameters.WorkArea.Width / 1.5;
Height = SystemParameters.WorkArea.Height / 1.5;
this.Loaded += MainWindow_Loaded;
private void MainWindow_Loaded(object sender, RoutedEventArgs e)
InitializeCamera();
private void ComboBoxCamera_SelectionChanged(object sender, SelectionChangedEventArgs e)
if (CameraArray.Count - 1 < CameraIndex)
return;
if (capCamera != null && cameraThread != null)
cameraThread.Abort();
StopDispose();
CreateCamera();
writeableBitmap = new WriteableBitmap(capCamera.FrameWidth, capCamera.FrameHeight, 0, 0, System.Windows.Media.PixelFormats.Bgra32, null);
imgViewport.Source = writeableBitmap;
private void InitializeCamera()
CameraArray = GetAllConnectedCameras();
List<string> GetAllConnectedCameras()
var cameraNames = new List<string>();
using (var searcher = new ManagementObjectSearcher("SELECT * FROM Win32_PnPEntity WHERE (PNPClass = 'Image' OR PNPClass = 'Camera')"))
foreach (var device in searcher.Get())
cameraNames.Add(device["Caption"].ToString());
return cameraNames;
void CreateCamera()
capCamera = new VideoCapture(CameraIndex);
capCamera.Fps = 30;
cameraThread = new Thread(PlayCamera);
cameraThread.Start();
private void PlayCamera()
while (capCamera != null && !capCamera.IsDisposed)
capCamera.Read(matImage);
if (matImage.Empty()) break;
//Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() =>
//
// var converted = Convert(BitmapConverter.ToBitmap(matImage));
// imgViewport.Source = converted;
//));
using (var img = BitmapConverter.ToBitmap(matImage))
var now = DateTime.Now;
var g = Graphics.FromImage(img);
var brush = new SolidBrush(System.Drawing.Color.Red);
g.DrawString($"北京时间: now.ToString("yyyy年MM月dd日 HH:mm:ss")", new System.Drawing.Font("Arial", 18), brush, new PointF(5, 5));
rectangle = new Rectangle(0, 0, img.Width, img.Height);
brush.Dispose();
g.Dispose();
Dispatcher.Invoke(new Action(() =>
WriteableBitmapHelper.BitmapCopyToWriteableBitmap(img, writeableBitmap, rectangle, 0, 0, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
));
;
Thread.Sleep(100);
private void StartRecording()
if (capCamera == null)
WPFDevelopers.Minimal.Controls.MessageBox.Show("未开启摄像机","提示",MessageBoxButton.OKCancel,MessageBoxImage.Error);
return;
var videoFile = System.IO.Path.Combine(System.Environment.CurrentDirectory, "Video");
if (!System.IO.Directory.Exists(videoFile))
System.IO.Directory.CreateDirectory(videoFile);
var currentTime = System.IO.Path.Combine(videoFile, $"DateTime.Now.ToString("yyyyMMddHHmmsshh").avi");
videoWriter = new VideoWriter(currentTime, FourCCValues.XVID, capCamera.Fps, new OpenCvSharp.Size(capCamera.FrameWidth, capCamera.FrameHeight));
writerThread = new Thread(AddCameraFrameToRecording);
writerThread.Start();
private void StopRecording()
if (videoWriter != null && !videoWriter.IsDisposed)
videoWriter.Release();
videoWriter.Dispose();
videoWriter = null;
private void AddCameraFrameToRecording()
var waitTimeBetweenFrames = 1_000 / capCamera.Fps;
var lastWrite = DateTime.Now;
while (!videoWriter.IsDisposed)
if (DateTime.Now.Subtract(lastWrite).TotalMilliseconds < waitTimeBetweenFrames)
continue;
lastWrite = DateTime.Now;
videoWriter.Write(matImage);
private void btStop_Click(object sender, RoutedEventArgs e)
StopDispose();
btStop.IsEnabled = false;
void StopDispose()
if (capCamera != null && capCamera.IsOpened())
capCamera.Dispose();
capCamera = null;
if (videoWriter != null && !videoWriter.IsDisposed)
videoWriter.Release();
videoWriter.Dispose();
videoWriter = null;
btPlay.IsEnabled = true;
GC.Collect();
void CreateRecord()
cameraThread = new Thread(PlayCamera);
cameraThread.Start();
BitmapImage Convert(Bitmap src)
System.Drawing.Image img = src;
var now = DateTime.Now;
var g = Graphics.FromImage(img);
var brush = new SolidBrush(System.Drawing.Color.Red);
g.DrawString($"北京时间: now.ToString("yyyy年MM月dd日 HH:mm:ss")", new System.Drawing.Font("Arial", 18), brush, new PointF(5, 5));
brush.Dispose();
g.Dispose();
var writeableBitmap = WriteableBitmapHelper.BitmapToWriteableBitmap(src);
return WriteableBitmapHelper.ConvertWriteableBitmapToBitmapImage(writeableBitmap);
protected override void OnClosing(CancelEventArgs e)
if(WPFDevelopers.Minimal.Controls.MessageBox.Show("是否关闭系统?", "询问", MessageBoxButton.OKCancel, MessageBoxImage.Question) != MessageBoxResult.OK)
e.Cancel = true;
return;
protected override void OnClosed(EventArgs e)
StopDispose();
private void btPlay_Click(object sender, RoutedEventArgs e)
btPlay.IsEnabled = false;
btStop.IsEnabled = true;
CreateCamera();
三、WriteableBitmapHelper.cs代码如下。
using System.IO;
using System.Windows;
using System.Windows.Media.Imaging;
namespace OpenCVSharpExample
public class WriteableBitmapHelper
//将Bitmap 转换成WriteableBitmap
public static WriteableBitmap BitmapToWriteableBitmap(System.Drawing.Bitmap src)
var wb = CreateCompatibleWriteableBitmap(src);
System.Drawing.Imaging.PixelFormat format = src.PixelFormat;
if (wb == null)
wb = new WriteableBitmap(src.Width, src.Height, 0, 0, System.Windows.Media.PixelFormats.Bgra32, null);
format = System.Drawing.Imaging.PixelFormat.Format32bppArgb;
BitmapCopyToWriteableBitmap(src, wb, new System.Drawing.Rectangle(0, 0, src.Width, src.Height), 0, 0, format);
return wb;
//创建尺寸和格式与Bitmap兼容的WriteableBitmap
public static WriteableBitmap CreateCompatibleWriteableBitmap(System.Drawing.Bitmap src)
System.Windows.Media.PixelFormat format;
switch (src.PixelFormat)
case System.Drawing.Imaging.PixelFormat.Format16bppRgb555:
format = System.Windows.Media.PixelFormats.Bgr555;
break;
case System.Drawing.Imaging.PixelFormat.Format16bppRgb565:
format = System.Windows.Media.PixelFormats.Bgr565;
break;
case System.Drawing.Imaging.PixelFormat.Format24bppRgb:
format = System.Windows.Media.PixelFormats.Bgr24;
break;
case System.Drawing.Imaging.PixelFormat.Format32bppRgb:
format = System.Windows.Media.PixelFormats.Bgr32;
break;
case System.Drawing.Imaging.PixelFormat.Format32bppPArgb:
format = System.Windows.Media.PixelFormats.Pbgra32;
break;
case System.Drawing.Imaging.PixelFormat.Format32bppArgb:
format = System.Windows.Media.PixelFormats.Bgra32;
break;
default:
return null;
return new WriteableBitmap(src.Width, src.Height, 0, 0, format, null);
//将Bitmap数据写入WriteableBitmap中
public static void BitmapCopyToWriteableBitmap(System.Drawing.Bitmap src, WriteableBitmap dst, System.Drawing.Rectangle srcRect, int destinationX, int destinationY, System.Drawing.Imaging.PixelFormat srcPixelFormat)
var data = src.LockBits(new System.Drawing.Rectangle(new System.Drawing.Point(0, 0), src.Size), System.Drawing.Imaging.ImageLockMode.ReadOnly, srcPixelFormat);
dst.WritePixels(new Int32Rect(srcRect.X, srcRect.Y, srcRect.Width, srcRect.Height), data.Scan0, data.Height * data.Stride, data.Stride, destinationX, destinationY);
src.UnlockBits(data);
public static BitmapImage ConvertWriteableBitmapToBitmapImage(WriteableBitmap wbm)
BitmapImage bmImage = new BitmapImage();
using (MemoryStream stream = new MemoryStream())
PngBitmapEncoder encoder = new PngBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(wbm));
encoder.Save(stream);
bmImage.BeginInit();
bmImage.CacheOption = BitmapCacheOption.OnLoad;
bmImage.StreamSource = stream;
bmImage.EndInit();
bmImage.Freeze();
return bmImage;
02
—
效果预览
鸣谢素材提供者 - 李付华
源码地址如下
Github:https://github.com/WPFDevelopersOrg
https://github.com/WPFDevelopersOrg/OpenCVSharpExample
Gitee:https://gitee.com/WPFDevelopersOrg
WPF开发者QQ群: 340500857
Github:https://github.com/WPFDevelopersOrg
出处:https://www.cnblogs.com/yanjinhua
版权:本作品采用「署名-非商业性使用-相同方式共享 4.0 国际」许可协议进行许可。
转载请著名作者 出处 https://github.com/WPFDevelopersOrg
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