Delphi - 利用DLL编程控制摄像头实现拍照、录制视频

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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：

  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.

运行效果：

 

  作者：Jeremy.Wu
  出处：https://www.cnblogs.com/jeremywucnblog/
  本文版权归作者和博客园共有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。

来源：https://www.cnblogs.com/jeremywucnblog/p/11554872.html