Delphi - 利用DLL编程控制摄像头实现拍照、录制视频

青春永不散 發表於 2019-9-20 09:15:00

Delphi - 利用DLL编程控制摄像头实现拍照、录制视频

Delphi利用avicap32.dll编程控制摄像头实现拍照、录制视频
项目需求：平板电脑（Windows系统）一维/二维码扫描功能；
需求分析：
需要扫描一维/二维码时，分两步实现。
第一步，avicap32.dll或者dspack技术实现静默打开摄像头拍照、保存BMP图片。
第二步，ZXing技术实现对一维/二维码的解析，最终获取到码值。
本篇是利用avicap32.dll技术实现拍照/录制视频的测试Demo。
请看代码：
<div class="cnblogs_code">
<pre>1 unit uMain;
2
3 interface
4
5 uses
6 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
7 Dialogs, ExtCtrls, StdCtrls, RzPanel, RzButton;
8
9 type
 10 TFrmMain = class(TForm)
 11 gbScreen: TRzGroupBox;
 12 gbOperation: TRzGroupBox;
 13 btnStart: TRzBitBtn;
 14 btnStop: TRzBitBtn;
 15 btnSaveBMP: TRzBitBtn;
 16 btnStartR: TRzBitBtn;
 17 btnSaveAVI: TRzBitBtn;
 18 pMain: TPanel;
 19 procedure btnStartClick(Sender: TObject);
 20 procedure FormClose(Sender: TObject; var Action: TCloseAction);
 21 procedure btnStopClick(Sender: TObject);
 22 procedure btnSaveBMPClick(Sender: TObject);
 23 procedure btnStartRClick(Sender: TObject);
 24 procedure btnSaveAVIClick(Sender: TObject);
 25 private
 26 { Private declarations }
 27 hWndC: THandle;
 28 public
 29 { Public declarations }
 30 end;
 31
 32 var
 33 FrmMain: TFrmMain;
 34 const WM_CAP_START = WM_USER;
 35 const WM_CAP_STOP = WM_CAP_START + 68;
 36 const WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10;
 37 const WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11;
 38 const WM_CAP_SAVEDIB = WM_CAP_START + 25;
 39 const WM_CAP_GRAB_FRAME = WM_CAP_START + 60;
 40 const WM_CAP_SEQUENCE = WM_CAP_START + 62;
 41 const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20;
 42 const WM_CAP_SEQUENCE_NOFILE = WM_CAP_START + 63;
 43 const WM_CAP_SET_OVERLAY = WM_CAP_START + 51;
 44 const WM_CAP_SET_PREVIEW = WM_CAP_START + 50;
 45 const WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START + 6;
 46 const WM_CAP_SET_CALLBACK_ERROR = WM_CAP_START + 2;
 47 const WM_CAP_SET_CALLBACK_STATUSA = WM_CAP_START + 3;
 48 const WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START + 5;
 49 const WM_CAP_SET_SCALE = WM_CAP_START + 53;
 50 const WM_CAP_SET_PREVIEWRATE = WM_CAP_START + 52;
 51
 52 function capCreateCaptureWindowA(lpszWindowName: PCHAR;
 53 dwStyle: longint; x: integer; y: integer; nWidth: integer;
 54 nHeight: integer; ParentWin: HWND; nId: integer): HWND;
 55 STDCALL EXTERNAL 'AVICAP32.DLL';
 56
 57 implementation
 58
 59 {$R *.dfm}
 60
 61 procedure TFrmMain.btnStartClick(Sender: TObject);
 62 begin
 63 //开始拍摄
 64 hWndC := capCreateCaptureWindowA('My Own Capture Window', WS_CHILD or WS_VISIBLE, pMain.Left, pMain.Top, pMain.Width, pMain.Height, FrmMain.Handle, 0);
 65 if hWndC <> 0 then
 66 begin
 67 SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0);
 68 SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0);
 69 SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0);
 70 SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0);
 71 SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0);
 72 SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0);
 73 SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);
 74 SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0);
 75 end;
 76 end;
 77
 78 procedure TFrmMain.FormClose(Sender: TObject; var Action: TCloseAction);
 79 begin
 80 //程序退出时，自动关闭摄像头
 81 if hWndC <> 0 then
 82 begin
 83 SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
 84 end;
 85 end;
 86
 87 procedure TFrmMain.btnStopClick(Sender: TObject);
 88 begin
 89 //关闭摄像头
 90 if hWndC <> 0 then
 91 begin
 92 SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
 93 hWndC := 0;
 94 end;
 95 end;
 96
 97 procedure TFrmMain.btnSaveBMPClick(Sender: TObject);
 98 begin
 99 //保存BMP
100 if hWndC <> 0 then
101 begin
102 SendMessage(hWndC, WM_CAP_SAVEDIB, 0, longint(pchar('D:/1.bmp')));
103 end;
104 end;
105
106 procedure TFrmMain.btnStartRClick(Sender: TObject);
107 begin
108 //开始录制AVI视频
109 if hWndC <> 0 then
110 begin
111 SendMessage(hWndC, WM_CAP_FILE_SET_CAPTURE_FILEA, 0, Longint(pchar('c:/test.avi')));
112 SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
113 end;
114 end;
115
116 procedure TFrmMain.btnSaveAVIClick(Sender: TObject);
117 begin
118 //停止录制并保存AVI视频
119 if hWndC <> 0 then
120 begin
121 SendMessage(hWndC, WM_CAP_STOP, 0, 0);
122 end;
123 end;
124
125 end.</pre>
</div>
运行效果：
<img src="https://img2018.cnblogs.com/blog/1335881/201909/1335881-20190920091357878-502149683.png" alt="">
 
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来源：https://www.cnblogs.com/jeremywucnblog/p/11554872.html

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Delphi - 利用DLL编程控制摄像头实现拍照、录制视频