用c#写的directshow简易视频播放器

很久没动directshow了，现在一直用c#写程序，突然看到directshow在.net下也有library，于是想试试在.net下的directshow。这个播放器是参照directshownet library中的例子改的，自己加了一些控制方面的。
先来看看效果图：

先说一下directshownet，这是一个用c#写的directshow类库，是一个开源项目，sourceforge主页：http://directshownet.sourceforge.net/ 不过这个项目关注的人不是很多，代码也很久没更新了，毕竟使用directshow的大都是c++项目，实现起来也是c++更高效。在.net里也可以调用VB的directshow类库来实现，不过我觉得这样太麻烦了，还是用directshownet这个现成的类库来的快。

首先从上面的sourceforge主页里下载directshownet library，现在最新的版本是2.1（还是2010的，汗），加入c#项目的引用中，然后using DirectShowLib,就可以使用其中的类了。

上完整代码：

1. using System;
2. using System.Collections.Generic;
3. using System.ComponentModel;
4. using System.Data;
5. using System.Drawing;
6. using System.Linq;
7. using System.Text;
8. using System.Windows.Forms;
9. using DirectShowLib;
10. using System.Threading;
11. using System.Runtime.InteropServices;
13. namespace DirectShow
14. {
15. public partial class Form1 : Form
16. {
17. private const int WMGraphNotify = 0x0400 + 13;
18. private Thread t = null;
19. private IGraphBuilder graphBuilder = null;
20. private IMediaControl mediaControl = null;
21. private IMediaEventEx mediaEventEx = null;
22. private IVideoWindow videoWindow = null;
23. private IBasicAudio basicAudio = null;
24. private IBasicVideo basicVideo = null;
25. private IMediaSeeking mediaSeeking = null;
26. private IMediaPosition mediaPosition = null;
27. private IVideoFrameStep frameStep = null;
29. public Form1()
30. {
31. InitializeComponent();
32. trackBar2.SetRange(-1000, 0);
33. }
35. private void updateTimeBar(double current)
36. {
38. }
40. private void updateTimeBarThread()
41. {
42. double time;
43. int volu;
44. while (true)
45. {
46. mediaPosition.get_CurrentPosition(out time);
47. Console.WriteLine(time);
48. basicAudio.get_Volume(out volu);
49. Console.WriteLine(volu);
50. this.BeginInvoke(new MethodInvoker(() =>
51. {
52. trackBar1.Value = (int)time;
53. }));
54. Thread.Sleep(1000);
55. }
56. }
58. private void button1_Click(object sender, EventArgs e)
59. {
60. int hr = 0;
61. if (this.graphBuilder == null)
62. {
63. String filename = textBox1.Text;
65. this.graphBuilder = (IGraphBuilder)new FilterGraph();
67. // Have the graph builder construct its the appropriate graph automatically
68. hr = this.graphBuilder.RenderFile(filename, null);
69. DsError.ThrowExceptionForHR(hr);
71. // QueryInterface for DirectShow interfaces
72. this.mediaControl = (IMediaControl)this.graphBuilder;
73. this.mediaEventEx = (IMediaEventEx)this.graphBuilder;
74. this.mediaSeeking = (IMediaSeeking)this.graphBuilder;
75. this.mediaPosition = (IMediaPosition)this.graphBuilder;
77. // Query for video interfaces, which may not be relevant for audio files
78. this.videoWindow = this.graphBuilder as IVideoWindow;
79. this.basicVideo = this.graphBuilder as IBasicVideo;
81. // Query for audio interfaces, which may not be relevant for video-only files
82. this.basicAudio = this.graphBuilder as IBasicAudio;
84. hr = this.mediaEventEx.SetNotifyWindow(this.Handle, WMGraphNotify, IntPtr.Zero);
85. DsError.ThrowExceptionForHR(hr);
86. // Setup the video window
87. hr = this.videoWindow.put_Owner(this.Handle);
88. DsError.ThrowExceptionForHR(hr);
90. hr = this.videoWindow.put_WindowStyle(WindowStyle.Child |
91. WindowStyle.ClipSiblings | WindowStyle.ClipChildren);
92. DsError.ThrowExceptionForHR(hr);
94. this.Focus();
96. hr = InitVideoWindow(1, 1);
97. DsError.ThrowExceptionForHR(hr);
98. double time;
99. mediaPosition.get_Duration(out time);
100. trackBar1.SetRange(0, (int)time);
101. t = new Thread(new ThreadStart(updateTimeBarThread));
102. t.IsBackground = true;
103. t.Start();
104. }
105. if (button1.Text.Equals("播放"))
106. {
107. // Run the graph to play the media file
108. hr = this.mediaControl.Run();
109. DsError.ThrowExceptionForHR(hr);
110. button1.Text = "暂停";
112. }
113. else
114. {
115. hr = this.mediaControl.Pause();
116. DsError.ThrowExceptionForHR(hr);
117. button1.Text = "播放";
118. }
120. }
122. private int InitVideoWindow(int nMultiplier, int nDivider)
123. {
124. int hr = 0;
125. int lHeight, lWidth;
127. if (this.basicVideo == null)
128. return 0;
130. // Read the default video size
131. hr = this.basicVideo.GetVideoSize(out lWidth, out lHeight);
132. if (hr == DsResults.E_NoInterface)
133. return 0;
135. // Account for requests of normal, half, or double size
136. lWidth = lWidth * nMultiplier / nDivider;
137. lHeight = lHeight * nMultiplier / nDivider;
139. this.ClientSize = new Size(lWidth, lHeight + 75);
140. Application.DoEvents();
142. hr = this.videoWindow.SetWindowPosition(0, 30, lWidth, lHeight);
144. return hr;
145. }
147. private void closeVideo()
148. {
149. int hr = 0;
151. // Stop media playback
152. if (this.mediaControl != null)
153. hr = this.mediaControl.Stop();
155. // Free DirectShow interfaces
156. CloseInterfaces();
157. button1.Text = "播放";
158. }
160. private void CloseInterfaces()
161. {
162. int hr = 0;
164. try
165. {
166. lock (this)
167. {
168. // Relinquish ownership (IMPORTANT!) after hiding video window
170. hr = this.videoWindow.put_Visible(OABool.False);
171. DsError.ThrowExceptionForHR(hr);
172. hr = this.videoWindow.put_Owner(IntPtr.Zero);
173. DsError.ThrowExceptionForHR(hr);
176. if (this.mediaEventEx != null)
177. {
178. hr = this.mediaEventEx.SetNotifyWindow(IntPtr.Zero, 0, IntPtr.Zero);
179. DsError.ThrowExceptionForHR(hr);
180. }
182. // Release and zero DirectShow interfaces
183. if (this.mediaEventEx != null)
184. this.mediaEventEx = null;
185. if (this.mediaSeeking != null)
186. this.mediaSeeking = null;
187. if (this.mediaPosition != null)
188. this.mediaPosition = null;
189. if (this.mediaControl != null)
190. this.mediaControl = null;
191. if (this.basicAudio != null)
192. this.basicAudio = null;
193. if (this.basicVideo != null)
194. this.basicVideo = null;
195. if (this.videoWindow != null)
196. this.videoWindow = null;
197. if (this.frameStep != null)
198. this.frameStep = null;
199. if (this.graphBuilder != null)
200. Marshal.ReleaseComObject(this.graphBuilder); this.graphBuilder = null;
202. GC.Collect();
203. }
204. }
205. catch
206. {
207. }
208. }
210. private void buttonStop_Click(object sender, EventArgs e)
211. {
212. closeVideo();
213. t.Abort();
214. }
216. private void trackBar1_ValueChanged(object sender, EventArgs e)
217. {
219. }
221. private void trackBar1_Scroll(object sender, EventArgs e)
222. {
223. if (mediaPosition != null)
224. {
225. mediaPosition.put_CurrentPosition(trackBar1.Value);
226. }
228. }
230. private void trackBar2_Scroll(object sender, EventArgs e)
231. {
232. if (basicAudio != null)
233. {
234. basicAudio.put_Volume(trackBar2.Value);
235. }
236. }
237. }
238. }

开头的成员变量都是directshow的接口，接触过directshow的一看他们的名字就应该知道他们的作用，我就不多说了。在点击开始播放按键后，接口实例化，然后我开启了一个线程——用于更新进度条。停止键就是开始键的反过程了，销毁接口和线程。
能力有限写的很简单，还有很多用法可以参考他自带的sample，都是很实用的demo。

from：https://wuyuans.com/2012/09/simple-media-player-using-csharp