我正在尝试制作一款使用相机录制视频并处理视频图像的应用.这就是我想要的.首先,我的应用程序使用Torch录制了10秒的视频.其次,我使用一种方法来播放视频以查看我录制的内容.
我坚持三件事.
如何将视频转换为单独的帧(图像)？
是否有可能在录制视频时异步转换视频？
当我将视频转换为单独的帧时,如何使用它们？它们是JPEG吗？我可以简单地将它们显示为图像吗？等等.
主要代码:
using System;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
namespace App3
{
public sealed partial class MainPage : Page
{
DispatcherTimer D;
double basetimer = 0;
public MainPage()
{
this.InitializeComponent();
this.NavigationCacheMode = NavigationCacheMode.Required;
D = new DispatcherTimer();
D.Interval = new TimeSpan(0, 0, 1);
D.Tick += timer_Tick;
txt.Text = basetimer.ToString();
Play.IsEnabled = false;
}
public Library Library = new Library();
public object PreviewImage { get; private set; }
void timer_Tick(object sender, object e)
{
basetimer = basetimer - 1;
txt.Text = basetimer.ToString();
if (basetimer == 0)
{
D.Stop();
Preview.Source = null;
Library.Stop();
Record.IsEnabled = false;
Play.IsEnabled = true;
Clear.IsEnabled = true;
if (Library._tc.Enabled)
{
Library._tc.Enabled = false;
}
}
}
private void Record_Click(object sender, RoutedEventArgs e)
{
if (Library.Recording)
{
Preview.Source = null;
Library.Stop();
Record.Icon = new SymbolIcon(Symbol.Video);
}
else
{
basetimer = 11;
D.Start();
//D.Tick += timer_Tick;
Display.Source = null;
Library.Record(Preview);
Record.Icon = new SymbolIcon(Symbol.VideoChat);
Record.IsEnabled = false;
Play.IsEnabled = false;
}
}
private async void Play_Click(object sender, RoutedEventArgs e)
{
await Library.Play(Dispatcher, Display);
//Extract_Image_From_Video(Library.buffer);
}
private void Clear_Click(object sender, RoutedEventArgs e)
{
Display.Source = null;
Record.Icon = new SymbolIcon(Symbol.Video);
txt.Text = "0";
basetimer= 0;
Play.IsEnabled = false;
Record.IsEnabled =true;
if (Library.capture != null)
{
D.Stop();
Library.Recording = false;
Preview.Source = null;
Library.capture.Dispose();
Library.capture = null;
basetimer = 11;
}
}
}
}
图书馆类:
using System;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Windows.Devices.Enumeration;
using Windows.Media.Capture;
using Windows.Media.Devices;
using Windows.Media.MediaProperties;
using Windows.Storage;
using Windows.Storage.Streams;
using Windows.UI.Core;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media.Imaging;
using Windows.Graphics.Imaging;
using Emgu.CV.Structure;
using Emgu.CV;
using System.Collections.Generic;
public class Library
{
private const string videoFilename = "video.mp4";
private string filename;
public MediaCapture capture;
public InMemoryRandomAccessStream buffer;
public static bool Recording;
public TorchControl _tc;
public int basetimer ;
public async Task init()
{
if (buffer != null)
{
buffer.Dispose();
}
buffer = new InMemoryRandomAccessStream();
if (capture != null)
{
capture.Dispose();
}
try
{
if (capture == null)
{
var allVideoDevices = await DeviceInformation.FindAllAsync(DeviceClass.VideoCapture);
DeviceInformation cameraDevice =
allVideoDevices.FirstOrDefault(x => x.EnclosureLocation != null &&
x.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Back);
capture = new MediaCapture();
var mediaInitSettings = new MediaCaptureInitializationSettings { VideoDeviceId = cameraDevice.Id };
// Initialize
try
{
await capture.InitializeAsync(mediaInitSettings);
var videoDev = capture.VideoDeviceController;
_tc = videoDev.TorchControl;
Recording = false;
_tc.Enabled = false;
}
catch (UnauthorizedAccessException)
{
Debug.WriteLine("UnauthorizedAccessExeption>>");
}
catch (Exception ex)
{
Debug.WriteLine("Exception when initializing MediaCapture with {0}: {1}", cameraDevice.Id, ex.ToString());
}
}
capture.Failed += (MediaCapture sender, MediaCaptureFailedEventArgs errorEventArgs) =>
{
Recording = false;
_tc.Enabled = false;
throw new Exception(string.Format("Code: {0}. {1}", errorEventArgs.Code, errorEventArgs.Message));
};
}
catch (Exception ex)
{
if (ex.InnerException != null && ex.InnerException.GetType() == typeof(UnauthorizedAccessException))
{
throw ex.InnerException;
}
throw;
}
return true;
}
public async void Record(CaptureElement preview)
{
await init();
preview.Source = capture;
await capture.StartPreviewAsync();
await capture.StartRecordToStreamAsync(MediaEncodingProfile.CreateMp4(VideoEncodingQuality.Auto), buffer);
if (Recording) throw new InvalidOperationException("cannot excute two records at the same time");
Recording = true;
_tc.Enabled = true;
}
public async void Stop()
{
await capture.StopRecordAsync();
Recording = false;
_tc.Enabled = false;
}
public async Task Play(CoreDispatcher dispatcher, MediaElement playback)
{
IRandomAccessStream video = buffer.CloneStream();
if (video == null) throw new ArgumentNullException("buffer");
StorageFolder storageFolder = Windows.ApplicationModel.Package.Current.InstalledLocation;
if (!string.IsNullOrEmpty(filename))
{
StorageFile original = await storageFolder.GetFileAsync(filename);
await original.DeleteAsync();
}
await dispatcher.RunAsync(CoreDispatcherPriority.Normal, async () =>
{
StorageFile storageFile = await storageFolder.CreateFileAsync(videoFilename, CreationCollisionOption.GenerateUniqueName);
filename = storageFile.Name;
using (IRandomAccessStream fileStream = await storageFile.OpenAsync(FileAccessMode.ReadWrite))
{
await RandomAccessStream.CopyAndCloseAsync(video.GetInputStreamAt(0), fileStream.GetOutputStreamAt(0));
await video.FlushAsync();
video.Dispose();
}
IRandomAccessStream stream = await storageFile.OpenAsync(FileAccessMode.Read);
playback.SetSource(stream, storageFile.FileType);
playback.Play();
});
}
Brendan Kend.. 10
在与Accord遇到许多麻烦之后，我最终使用MediaToolkit解决了类似的问题。
我需要为视频的每一秒保存一个图像：
using (var engine = new Engine())
{
var mp4 = new MediaFile { Filename = mp4FilePath };
engine.GetMetadata(mp4);
var i = 0;
while (i < mp4.Metadata.Duration.Seconds)
{
var options = new ConversionOptions { Seek = TimeSpan.FromSeconds(i) };
var outputFile = new MediaFile { Filename = string.Format("{0}\\image-{1}.jpeg", outputPath, i) };
engine.GetThumbnail(mp4, outputFile, options);
i++;
}
}
希望有一天能对某人有所帮助。
在与Accord遇到许多麻烦之后，我最终使用MediaToolkit解决了类似的问题。
我需要为视频的每一秒保存一个图像：
using (var engine = new Engine())
{
var mp4 = new MediaFile { Filename = mp4FilePath };
engine.GetMetadata(mp4);
var i = 0;
while (i < mp4.Metadata.Duration.Seconds)
{
var options = new ConversionOptions { Seek = TimeSpan.FromSeconds(i) };
var outputFile = new MediaFile { Filename = string.Format("{0}\\image-{1}.jpeg", outputPath, i) };
engine.GetThumbnail(mp4, outputFile, options);
i++;
}
}
希望有一天能对某人有所帮助。
我昨天才知道这件事.
这是一个完整且易于理解的示例,它选择视频文件并在第一秒视频中保存快照.
您可以拍摄适合您项目的部分并更改其中一些(即从相机获取视频分辨率)
1)和3)
TimeSpan timeOfFrame = new TimeSpan(0, 0, 1);
//pick mp4 file
var picker = new Windows.Storage.Pickers.FileOpenPicker();
picker.SuggestedStartLocation = Windows.Storage.Pickers.PickerLocationId.VideosLibrary;
picker.FileTypeFilter.Add(".mp4");
StorageFile pickedFile = await picker.PickSingleFileAsync();
if (pickedFile == null)
{
return;
}
///
//Get video resolution
List encodingPropertiesToRetrieve = new List();
encodingPropertiesToRetrieve.Add("System.Video.FrameHeight");
encodingPropertiesToRetrieve.Add("System.Video.FrameWidth");
IDictionary encodingProperties = await pickedFile.Properties.RetrievePropertiesAsync(encodingPropertiesToRetrieve);
uint frameHeight = (uint)encodingProperties["System.Video.FrameHeight"];
uint frameWidth = (uint)encodingProperties["System.Video.FrameWidth"];
///
//Use Windows.Media.Editing to get ImageStream
var clip = await MediaClip.CreateFromFileAsync(pickedFile);
var composition = new MediaComposition();
composition.Clips.Add(clip);
var imageStream = await composition.GetThumbnailAsync(timeOfFrame, (int)frameWidth, (int)frameHeight, VideoFramePrecision.NearestFrame);
///
//generate bitmap
var writableBitmap = new WriteableBitmap((int)frameWidth, (int)frameHeight);
writableBitmap.SetSource(imageStream);
//generate some random name for file in PicturesLibrary
var saveAsTarget = await KnownFolders.PicturesLibrary.CreateFileAsync("IMG" + Guid.NewGuid().ToString().Substring(0, 4) + ".jpg");
//get stream from bitmap
Stream stream = writableBitmap.PixelBuffer.AsStream();
byte[] pixels = new byte[(uint)stream.Length];
await stream.ReadAsync(pixels, 0, pixels.Length);
using (var writeStream = await saveAsTarget.OpenAsync(FileAccessMode.ReadWrite))
{
var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, writeStream);
encoder.SetPixelData(
BitmapPixelFormat.Bgra8,
BitmapAlphaMode.Premultiplied,
(uint)writableBitmap.PixelWidth,
(uint)writableBitmap.PixelHeight,
96,
96,
pixels);
await encoder.FlushAsync();
using (var outputStream = writeStream.GetOutputStreamAt(0))
{
await outputStream.FlushAsync();
}
}
如果要在xaml Image中显示帧,则应使用imageStream
BitmapImage bitmapImage = new BitmapImage(); bitmapImage.SetSource(imageStream); XAMLImage.Source = bitmapImage;
如果你想提取更多帧,也有 composition.GetThumbnailsAsync
2)当你的计时器滴答作响时,使用你的mediaCapture
使用ffmpeg并安装Accord.Video.FFMPEG
using (var vFReader = new VideoFileReader())
{
vFReader.Open("video.mp4");
for (int i = 0; i < vFReader.FrameCount; i++)
{
Bitmap bmpBaseOriginal = vFReader.ReadVideoFrame();
}
vFReader.Close();
}
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