系統狀态:
1, Windows10 1909(内部版本 18363.778)
2,Visual Studio Community 2017 (Version 15.9.16)
3,已安裝Windows 10 SDK
4,.Net Framework 4.8
網上介紹有幾個方法:Nuget的WPFMediaKit、MediaCaptureWPF以及.Net自帶的MediaCapture、CameraCaptureUI
WPFMediaKit好像預設隻能将camera的畫面儲存成為image file不能直接讀取目前幀的資料;MediaCaptureWPF無法build成為any cpu platform;CameraCaptureUI會使用預設的UWP UI。。。
是以我們隻能用MediaCapture,官方教程:https://docs.microsoft.com/en-us/windows/uwp/audio-video-camera/basic-photo-video-and-audio-capture-with-mediacapture
因為我們的是WPF App,是以無法直接調用UWP API。
有三個方法可以讓WPF程式,調用UWP API:
1,NuGet下載下傳UwpDesktop(強烈不建議!它支援的API太久沒更新,實際使用的時候經常有各種問題)
2,在安裝Windows10 SDK之後,手動在project references裡添加以下兩個檔案的引用:
C:\Program Files (x86)\Windows Kits\10\UnionMetadata\Windows.winmd
C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v4.5\System.Runtime.WindowsRuntime.dll
3,.Net 4.6+或者.Net Core3.0+,并且Windows10是1803版本之後,可以NuGet下載下傳Microsoft.Windows.SDK.Contracts
以上方式,最好都自動将 NuGet 包的引用方式從 packages.config 更新為 PackageReference。否則運作時可能會出錯。
準備好讓WPF調用WinRT API之後,為了讓WPF顯示攝像頭畫面,我們還需要在NuGet下載下傳MMaitre.MediaCaptureWPF。
但是這玩意不能編譯成為any CPU,是以隻能将項目轉為x64。
準備妥當,代碼就很容易了:
using MediaCaptureWPF;
using System;
using System.Windows;
using Windows.Media.Capture;
------------------------------------
private MediaCapture captureManager;
private async void Window_Loaded(object sender, RoutedEventArgs e)
{
captureManager = new MediaCapture();
await captureManager.InitializeAsync();
var preview = new CapturePreview(captureManager);
this.webCamImage.Source = preview; //XAML頁面的一個Image控件
await preview.StartAsync();
}
這樣,當程式跑起來,就能在UI界面看到攝像頭的實時畫面了。
如果想擷取攝像頭某一時刻的byte data,就有點麻煩:
var lowLagCapture = await captureManager.PrepareLowLagPhotoCaptureAsync(ImageEncodingProperties.CreateUncompressed(MediaPixelFormat.Bgra8));
var capturedPhoto = await lowLagCapture.CaptureAsync();
using (var softwareBitmap = capturedPhoto.Frame.SoftwareBitmap)
{
Task<byte[]> bytes = await GetPixelBytesFromSoftwareBitmapAsync(softwareBitmap));
}
await lowLagCapture.FinishAsync();
------------------------------------------------------
public static async Task<byte[]> GetPixelBytesFromSoftwareBitmapAsync(SoftwareBitmap softwareBitmap)
{
using (InMemoryRandomAccessStream stream = new InMemoryRandomAccessStream())
{
Windows.Graphics.Imaging.BitmapEncoder encoder = await Windows.Graphics.Imaging.BitmapEncoder.CreateAsync(Windows.Graphics.Imaging.BitmapEncoder.JpegEncoderId, stream);
encoder.SetSoftwareBitmap(softwareBitmap);
await encoder.FlushAsync();
// Read the pixel bytes from the memory stream
using (var reader = new DataReader(stream.GetInputStreamAt(0)))
{
var bytes = new byte[stream.Size];
await reader.LoadAsync((uint)stream.Size);
reader.ReadBytes(bytes);
return bytes;
}
}
}