WPF 展示视频修改为WriteableBitmap

Posted 2022-02-28 dotNET跨平台

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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：

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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;

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效果预览