TVideoCapture类的源码，继承TCustomPanel，用于视频捕获（用到了SendMessage和SetWindowPos等API）good

1. unit VideoCapture;
2. interface
3. uses
4. Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
5. Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Vcl.ExtCtrls, Vcl.Imaging.jpeg;
6. type
7. TVideoCapture = class(TCustomPanel)
8. private
9. hWndC: THandle;
10. CapturingAVI: bool;
11. procedure WMSize(var Message: TWMSize); message WM_SIZE;
12. protected
13. { Protected declarations }
14. public
15. constructor Create(AOwner: TComponent); override;
16. destructor Destroy; override;
17. procedure OpenVideo(handle: THandle);
18. procedure CloseVideo;
19. procedure GrabFrame;
20. procedure StartVideo;
21. procedure StopVideo;
22. procedure SaveBitMap(filename: TFileName);
23. procedure SaveJpeg(filename: TFileName; compressibility: Integer);
24. procedure SavetoJpegStream(var JpegStream: TMemoryStream; compressibility: Integer);
25. function StartAvi(filename: TFileName): Boolean;
26. procedure StopAvi;
27. procedure SetVideoFormat;
28. procedure SetSource;
29. procedure SetStretch(TrueorFalse: Boolean = true);
30. procedure SetCompression;
31. published
32. property Align;
33. end;
34. procedure Register;
35. implementation
36. const
37. WM_CAP_START = WM_USER;
38. WM_CAP_GET_CAPSTREAMPTR = (WM_CAP_START + 1);
39. WM_CAP_SET_CALLBACK_ERROR = (WM_CAP_START + 2);
40. WM_CAP_SET_CALLBACK_STATUS = (WM_CAP_START + 3);
41. WM_CAP_SET_CALLBACK_YIELD = (WM_CAP_START + 4);
42. WM_CAP_SET_CALLBACK_FRAME = (WM_CAP_START + 5);
43. WM_CAP_SET_CALLBACK_VIDEOSTREAM = (WM_CAP_START + 6);
44. WM_CAP_SET_CALLBACK_WAVESTREAM = (WM_CAP_START + 7);
45. WM_CAP_GET_USER_DATA = (WM_CAP_START + 8);
46. WM_CAP_SET_USER_DATA = (WM_CAP_START + 9);
47. WM_CAP_DRIVER_CONNECT = (WM_CAP_START + 10);
48. WM_CAP_DRIVER_DISCONNECT = (WM_CAP_START + 11);
49. WM_CAP_DRIVER_GET_NAME = (WM_CAP_START + 12);
50. WM_CAP_DRIVER_GET_VERSION = (WM_CAP_START + 13);
51. WM_CAP_DRIVER_GET_CAPS = (WM_CAP_START + 14);
52. WM_CAP_FILE_SET_CAPTURE_FILE = (WM_CAP_START + 20);
53. WM_CAP_FILE_GET_CAPTURE_FILE = (WM_CAP_START + 21);
54. WM_CAP_FILE_ALLOCATE = (WM_CAP_START + 22);
55. WM_CAP_FILE_SAVEAS = (WM_CAP_START + 23);
56. WM_CAP_FILE_SET_INFOCHUNK = (WM_CAP_START + 24);
57. WM_CAP_FILE_SAVEDIB = (WM_CAP_START + 25);
58. WM_CAP_EDIT_COPY = (WM_CAP_START + 30);
59. WM_CAP_SET_AUDIOFORMAT = (WM_CAP_START + 35);
60. WM_CAP_GET_AUDIOFORMAT = (WM_CAP_START + 36);
61. WM_CAP_DLG_VIDEOFORMAT = (WM_CAP_START + 41);
62. WM_CAP_DLG_VIDEOSOURCE = (WM_CAP_START + 42);
63. WM_CAP_DLG_VIDEODISPLAY = (WM_CAP_START + 43);
64. WM_CAP_GET_VIDEOFORMAT = (WM_CAP_START + 44);
65. WM_CAP_SET_VIDEOFORMAT = (WM_CAP_START + 45);
66. WM_CAP_DLG_VIDEOCOMPRESSION = (WM_CAP_START + 46);
67. WM_CAP_SET_PREVIEW = (WM_CAP_START + 50);
68. WM_CAP_SET_OVERLAY = (WM_CAP_START + 51);
69. WM_CAP_SET_PREVIEWRATE = (WM_CAP_START + 52);
70. WM_CAP_SET_SCALE = (WM_CAP_START + 53);
71. WM_CAP_GET_STATUS = (WM_CAP_START + 54);
72. WM_CAP_SET_SCROLL = (WM_CAP_START + 55);
73. WM_CAP_GRAB_FRAME = (WM_CAP_START + 60);
74. WM_CAP_GRAB_FRAME_NOSTOP = (WM_CAP_START + 61);
75. WM_CAP_SEQUENCE = (WM_CAP_START + 62);
76. WM_CAP_SEQUENCE_NOFILE = (WM_CAP_START + 63);
77. WM_CAP_SET_SEQUENCE_SETUP = (WM_CAP_START + 64);
78. WM_CAP_GET_SEQUENCE_SETUP = (WM_CAP_START + 65);
79. WM_CAP_SET_MCI_DEVICE = (WM_CAP_START + 66);
80. WM_CAP_GET_MCI_DEVICE = (WM_CAP_START + 67);
81. WM_CAP_STOP = (WM_CAP_START + 68);
82. WM_CAP_ABORT = (WM_CAP_START + 69);
83. WM_CAP_SINGLE_FRAME_OPEN = (WM_CAP_START + 70);
84. WM_CAP_SINGLE_FRAME_CLOSE = (WM_CAP_START + 71);
85. WM_CAP_SINGLE_FRAME = (WM_CAP_START + 72);
86. WM_CAP_PAL_OPEN = (WM_CAP_START + 80);
87. WM_CAP_PAL_SAVE = (WM_CAP_START + 81);
88. WM_CAP_PAL_PASTE = (WM_CAP_START + 82);
89. WM_CAP_PAL_AUTOCREATE = (WM_CAP_START + 83);
90. WM_CAP_PAL_MANUALCREATE = (WM_CAP_START + 84);
91. function capCreateCaptureWindowA(lpszWindowName: PCHAR;
92. dwStyle: longint;
93. x: integer;
94. y: integer;
95. nWidth: integer;
96. nHeight: integer;
97. ParentWin: HWND;
98. nId: integer): HWND; stdcall; external 'avicap32.dll';
99. procedure Register;
100. begin
101. RegisterComponents('FstiCtl', [TVideoCapture]);
102. end;
103. { TVideoCapture }
104. constructor TVideoCapture.Create(AOwner: TComponent);
105. begin
106. inherited Create(AOwner);
107. CapturingAVI := false;
108. Color := clBlack;
109. BevelOuter := bvNone;
110. Width := 320;
111. Height := 240;
112. hWndC := 0;
113. end;
114. destructor TVideoCapture.Destroy;
115. begin
116. if CapturingAVI then StopAvi;
117. if hWndC <> 0 then CloseVideo;
118. hWndC := 0;
119. inherited;
120. end;
121. procedure TVideoCapture.OpenVideo(handle: THandle);
122. begin
123. hWndC := capCreateCaptureWindowA('Video Capture Window',
124. WS_CHILD or WS_VISIBLE,
125. Left,
126. Top,
127. Width,
128. Height,
129. Handle,
130. 0);
131. if hWndC <> 0 then
132. SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0);
133. end;
134. procedure TVideoCapture.CloseVideo;
135. begin
136. if hWndC <> 0 then begin
137. SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
138. SendMessage(hWndC, WM_CLOSE, 0, 0);
139. hWndC := 0;
140. end;
141. end;
142. procedure TVideoCapture.GrabFrame;
143. begin
144. if hWndC <> 0 then
145. SendMessage(hWndC, WM_CAP_GRAB_FRAME, 0, 0);
146. end;
147. procedure TVideoCapture.SaveBitMap(filename: TFileName);
148. begin
149. SendMessage(hWndC, WM_CAP_FILE_SAVEDIB, 0, longint(pchar(FileName)));
150. end;
151. function TVideoCapture.StartAvi(filename: TFileName): Boolean;
152. begin
153. if hWndC <> 0 then begin
154. CapturingAVI := true;
155. SendMessage(hWndC,
156. WM_CAP_FILE_SET_CAPTURE_FILE,
157. 0,
158. Longint(pchar(FileName)));
159. SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
160. end;
161. end;
162. procedure TVideoCapture.StopAvi;
163. begin
164. if hWndC <> 0 then begin
165. SendMessage(hWndC, WM_CAP_STOP, 0, 0);
166. CapturingAVI := false;
167. end;
168. end;
169. procedure TVideoCapture.SaveJpeg(filename: TFileName;
170. compressibility: Integer);
171. var
172. bmp: TBitMap;
173. jpg: TJpegimage;
174. begin
175. try
176. SaveBitMap('tmp.bmp');
177. bmp := TBitmap.Create;
178. jpg := TJpegImage.Create;
179. bmp.LoadFromFile('tmp.bmp');
180. jpg.Assign(bmp);
181. jpg.CompressionQuality := compressibility;
182. jpg.Compress;
183. jpg.SaveToFile(filename);
184. DeleteFile('tmp.bmp');
185. except
186. end;
187. bmp.free;
188. jpg.free;
189. end;
190. procedure TVideoCapture.SetVideoFormat;
191. begin
192. SendMessage(hWndC, WM_CAP_DLG_VIDEOFORMAT, 0, 0);
193. end;
194. procedure TVideoCapture.SetSource;
195. begin
196. SendMessage(hWndC, WM_CAP_DLG_VIDEOSOURCE, 0, 0);
197. end;
198. procedure TVideoCapture.StartVideo;
199. begin
200. SendMessage(hWndC, WM_CAP_SET_PREVIEW, -1, 0);
201. SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 100, 0);
202. SendMessage(hWndC, WM_CAP_SET_SCALE, -1, 0);
203. end;
204. procedure TVideoCapture.StopVideo;
205. begin
206. SendMessage(hWndC, WM_CAP_SET_PREVIEW, 0, 0);
207. end;
208. procedure TVideoCapture.WMSize(var Message: TWMSize);
209. begin
210. SetWindowPos(hWndC, HWND_BOTTOM, 0, 0, Width, Height, SWP_NOMOVE or SWP_NOACTIVATE);
211. end;
212. procedure TVideoCapture.SetStretch(TrueorFalse: Boolean);
213. begin
214. end;
215. procedure TVideoCapture.SetCompression;
216. begin
217. SendMessage(hWndC, WM_CAP_DLG_VIDEOCOMPRESSION, 0, 0)
218. end;
219. procedure TVideoCapture.SavetoJpegStream(var JpegStream: TMemoryStream; compressibility: Integer);
220. var
221. bmp: TBitMap;
222. jpg: TJpegimage;
223. begin
224. try
225. SaveBitMap('tmp.bmp');
226. bmp := TBitmap.Create;
227. jpg := TJpegImage.Create;
228. bmp.LoadFromFile('tmp.bmp');
229. jpg.Assign(bmp);
230. jpg.CompressionQuality := compressibility;
231. jpg.Compress;
232. jpg.SaveToStream(JpegStream);
233. DeleteFile('tmp.bmp');
234. except
235. end;
236. bmp.free;
237. jpg.free;
238. end;
239. end.

 

http://blog.csdn.net/huang_xw/article/details/8638309