using System;
using System.Diagnostics;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Runtime.InteropServices;
using DirectShowLib;
using System.Windows.Forms;
using System.Collections.Generic;
namespace Polkan.DataSource
{
internal class WmvAdapter : ISampleGrabberCB, IDisposable
{
#region Fields
//public Image img;
private IFilterGraph2 _filterGraph;
private IMediaControl _mediaCtrl;
private IMediaEvent _mediaEvent;
private int _width;
private int _height;
private readonly string _outFolder;
private int _frameId;
#endregion
#region Constructors and Destructors
public WmvAdapter(string file, string outFolder)
{
_outFolder = outFolder;
try
{
SetupGraph(file);
}
catch
{
Dispose();
MessageBox.Show("A codec is required to load this video file. Please use http://www.headbands.com/gspot/ or search the web for the correct codec");
throw;
}
}
~WmvAdapter()
{
CloseInterfaces();
}
#endregion
public void Dispose()
{
CloseInterfaces();
}
public void Start()
{
int hr = _mediaCtrl.Run();
WaitUntilDone();
DsError.ThrowExceptionForHR(hr);
}
public void WaitUntilDone()
{
int hr;
const int eAbort = unchecked((int)0x80004004);
do
{
System.Windows.Forms.Application.DoEvents();
EventCode evCode;
hr = _mediaEvent.WaitForCompletion(100, out evCode);
} while
(hr == eAbort);
DsError.ThrowExceptionForHR(hr);
}
/// <summary> build the capture graph for grabber. </summary>
private void SetupGraph(string file)
{
ISampleGrabber sampGrabber = null;
IBaseFilter capFilter = null;
IBaseFilter nullrenderer = null;
_filterGraph = (IFilterGraph2)new FilterGraph();
_mediaCtrl = (IMediaControl)_filterGraph;
_mediaEvent = (IMediaEvent)_filterGraph;
var mediaFilt = (IMediaFilter)_filterGraph;
try
{
// Add the video source
int hr = _filterGraph.AddSourceFilter(file, "Ds.NET FileFilter", out capFilter);
DsError.ThrowExceptionForHR(hr);
// Get the SampleGrabber interface
sampGrabber = new SampleGrabber() as ISampleGrabber;
var baseGrabFlt = sampGrabber as IBaseFilter;
ConfigureSampleGrabber(sampGrabber);
// Add the frame grabber to the graph
hr = _filterGraph.AddFilter(baseGrabFlt, "Ds.NET Grabber");
DsError.ThrowExceptionForHR(hr);
// ---------------------------------
// Connect the file filter to the sample grabber
// Hopefully this will be the video pin, we could check by reading it's mediatype
IPin iPinOut = DsFindPin.ByDirection(capFilter, PinDirection.Output, 0);
// Get the input pin from the sample grabber
IPin iPinIn = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Input, 0);
hr = _filterGraph.Connect(iPinOut, iPinIn);
DsError.ThrowExceptionForHR(hr);
// Add the null renderer to the graph
nullrenderer = new NullRenderer() as IBaseFilter;
hr = _filterGraph.AddFilter(nullrenderer, "Null renderer");
DsError.ThrowExceptionForHR(hr);
// ---------------------------------
// Connect the sample grabber to the null renderer
iPinOut = DsFindPin.ByDirection(baseGrabFlt, PinDirection.Output, 0);
iPinIn = DsFindPin.ByDirection(nullrenderer, PinDirection.Input, 0);
hr = _filterGraph.Connect(iPinOut, iPinIn);
DsError.ThrowExceptionForHR(hr);
// Turn off the clock. This causes the frames to be sent
// thru the graph as fast as possible
hr = mediaFilt.SetSyncSource(null);
DsError.ThrowExceptionForHR(hr);
// Read and cache the image sizes
SaveSizeInfo(sampGrabber);
}
finally
{
if (capFilter != null)
{
Marshal.ReleaseComObject(capFilter);
}
if (sampGrabber != null)
{
Marshal.ReleaseComObject(sampGrabber);
}
if (nullrenderer != null)
{
Marshal.ReleaseComObject(nullrenderer);
}
GC.Collect();
}
}
private void SaveSizeInfo(ISampleGrabber sampGrabber)
{
// Get the media type from the SampleGrabber
var media = new AMMediaType();
int hr = sampGrabber.GetConnectedMediaType(media);
DsError.ThrowExceptionForHR(hr);
if ((media.formatType != FormatType.VideoInfo) || (media.formatPtr == IntPtr.Zero))
{
throw new NotSupportedException("Unknown Grabber Media Format");
}
// Grab the size info
var videoInfoHeader = (VideoInfoHeader)Marshal.PtrToStructure(media.formatPtr, typeof(VideoInfoHeader));
_width = videoInfoHeader.BmiHeader.Width;
_height = videoInfoHeader.BmiHeader.Height;
DsUtils.FreeAMMediaType(media);
GC.Collect();
}
private void ConfigureSampleGrabber(ISampleGrabber sampGrabber)
{
var media = new AMMediaType
{
majorType = MediaType.Video,
subType = MediaSubType.RGB24,
formatType = FormatType.VideoInfo
};
int hr = sampGrabber.SetMediaType(media);
DsError.ThrowExceptionForHR(hr);
DsUtils.FreeAMMediaType(media);
GC.Collect();
hr = sampGrabber.SetCallback(this, 1);
DsError.ThrowExceptionForHR(hr);
}
private void CloseInterfaces()
{
try
{
if (_mediaCtrl != null)
{
_mediaCtrl.Stop();
_mediaCtrl = null;
}
}
catch (Exception ex)
{
Debug.WriteLine(ex);
}
if (_filterGraph != null)
{
Marshal.ReleaseComObject(_filterGraph);
_filterGraph = null;
}
GC.Collect();
}
int ISampleGrabberCB.SampleCB(double sampleTime, IMediaSample pSample)
{
Marshal.ReleaseComObject(pSample);
return 0;
}
//add a boolean property to indicate the save-mode
public bool SaveToDisc { get; set; }
//the list for the bitmaps
public List<Bitmap> Images { get; set; }
int ISampleGrabberCB.BufferCB(double sampleTime, IntPtr pBuffer, int bufferLen)
{
using (var bitmap = new Bitmap(_width, _height, _width * 3, PixelFormat.Format24bppRgb, pBuffer))
{
bitmap.RotateFlip(RotateFlipType.Rotate180FlipX);
if (SaveToDisc)
{
String tempFile = _outFolder + _frameId + ".bmp";
if (File.Exists(tempFile))
{
}
else
{
bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp"));
}
_frameId++;
}
else
{
if (Images == null)
Images = new List<Bitmap>();
Images.Add((Bitmap)bitmap.Clone());
}
}
return 0;
}
}
}
该类正在将视频文件中的帧提取到硬盘。
在我的例子中，例如硬盘上的47个文件。
在类的底部我正在保存到硬盘：
bitmap.Save(Path.Combine(_outFolder, _frameId.ToString("D6") + ".bmp"));
在课堂上面有一个叫做WaitUntillDone（）的函数，帮助我。
我想要的是，当它完成将所有文件提取到硬盘时，它会给我一个messagebox.show或只是标签上的消息或者说“过程已经完成”
在Form1按钮中，使用如下所示的类单击事件：
wmv = new Polkan.DataSource.WmvAdapter(@"d:\VIDEO0040.3gp", sf);
wmv.SaveToDisc = true;
wmv.Start();
视频名称，sf是在硬盘上提取的目录。
然后是的，所以它会将它保存到硬盘而不是内存帧。
然后开始。
我也可以在按钮点击事件wmv.WaitUntillDone（）中的Form1中执行;但它完成后不会抛出任何信息或其他东西。
答案 0 :(得分：1)
您需要使用事件来告诉您的UI组件该流程已完成：
public event EventHandler ProcessFinished;
在你的方法中，当它完成时让它引发事件：
if(ProcessFinished != null)
ProcessFinished(this, EventArgs.Empty);
最后，在调用该过程的类中：
wmv = new Polkan.DataSource.WmvAdapter(@"d:\VIDEO0040.3gp", sf);
wmv.SaveToDisc = true;
wmv.ProcessFinished += OnProcessFinished;
wmv.Start();
OnProcessFinished的位置如下：
public void OnProcessFinished(object sender, EventArgs e){
MessageBox.Show("done!");
}
希望它有所帮助。
答案 1 :(得分：1)
您已经实现了自己的使用DoEvents（）的WaitUntil方法。这很棘手，很难做到。
将相关代码移动到Backgoundworker要简单得多。然后使用Completed事件来表示结束。
答案 2 :(得分：0)
WaitUntilDone循环让您的UI响应，直到整个文件播放完毕，您的所有通话都会为每个视频帧而烦恼。您可以将MessageBox.Show添加到WaitUntilDone的底部。
为了避免这种循环而不对外部消息循环产生控制，应用程序通常以不同的方式进行。他们使用IMediaEventEx.SetNotifyWindow订阅过滤器图形事件，并在播放完成时收到一条窗口消息。也就是说，一旦文件处理完成，您就会收到一条消息，您的处理程序有机会完成它必须做的事情。
这里可能更简单的选择是不执行任何WaitUntilDone而是使用计时器进行轮询，例如每秒一次，使用IMediaEvent.WaitForCompletion(0, ...来查看处理是否已完成。