利用Delphi編程式控制制網路攝影機(圖)

你的電腦有沒有網路攝影機？看到別人用QQ玩視屏你會不會去想怎麼實現的？這裡介紹使用DELPHI使用MS的
AVICAP32.DLL就可輕鬆的實現對網路攝影機編程，如果再加上你的網路編程水平，實現一個視屏聊天就不成什麼問題了。

　　看看下面代
碼的代碼：

const WM_CAP_START = WM_USER; const WM_CAP_STOP = WM_CAP_START + 68; const WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10; const WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11; const WM_CAP_SAVEDIB = WM_CAP_START + 25; const WM_CAP_GRAB_FRAME = WM_CAP_START + 60; const WM_CAP_SEQUENCE = WM_CAP_START + 62; const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20; const WM_CAP_SEQUENCE_NOFILE =WM_CAP_START+ 63 const WM_CAP_SET_OVERLAY =WM_CAP_START+ 51 const WM_CAP_SET_PREVIEW =WM_CAP_START+ 50 const WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6; const WM_CAP_SET_CALLBACK_ERROR=WM_CAP_START +2; const WM_CAP_SET_CALLBACK_STATUSA= WM_CAP_START +3; const WM_CAP_SET_CALLBACK_FRAME= WM_CAP_START +5; const WM_CAP_SET_SCALE=WM_CAP_START+ 53 const WM_CAP_SET_PREVIEWRATE=WM_CAP_START+ 52 function capCreateCaptureWindowA(lpszWindowName : PCHAR; dwStyle : longint; x : integer; y : integer;nWidth : integer;nHeight : integer;ParentWin : HWND; nId : integer): HWND;STDCALL EXTERNAL 'AVICAP32.DLL';

　
　上面的代碼就是我們主要用到的一個函數和常量的定義。

　　好了，開啟你的Delphi，建立一個工程，將上面的定義加上吧。

　
　建立一個視窗，放個Panel上去，添加一個按鈕，Caption設定為"開始"這裡需要定義一個全域變數，var hWndC : THandle;
開始按鈕代碼如下：

begin hWndC := capCreateCaptureWindowA('My Own Capture Window',WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0); hWndC := capCreateCaptureWindowA('My Own Capture Window',WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0); if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0); SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0); SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0); SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0); SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0); SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0); SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0); SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0); end; 　　按F9運行一下，怎麼樣，是不是可以看到網路攝影機的視屏了？那怎麼停下來？再加個按鈕caption設定成" 停止" 。代碼如下： if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0); hWndC := 0; end;

　
　視屏截到了，怎麼把它給儲存下來呢？下面按兩種方式儲存，一個是BMP靜態圖，一個是AVI動畫。

　　再放三個按鈕到表單上
去，caption分別設定成"儲存BMP"、"開始錄影"、"停止錄影"，三個按鈕的代碼分別如下：

//儲存BMP if hWndC <> 0 then begin SendMessage(hWndC,WM_CAP_SAVEDIB,0,longint(pchar('c:/test.bmp'))); end; // 開始錄影 if hWndC <> 0 then begin SendMessage(hWndC,WM_CAP_FILE_SET_CAPTURE_FILEA,0, Longint(pchar('c:/test.avi'))); SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0); end; //停止錄影 if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_STOP, 0, 0); end;

　　再運行看看吧。。
可以儲存幾張圖看看，也可以錄成AVI以後慢慢欣賞。

　　程式運行效果：

完整的程式碼如下：

unit Unit1; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls; type TForm1 = class(TForm) Panel1: TPanel; Button1: TButton; Button2: TButton; Button3: TButton; Button4: TButton; Button5: TButton; procedure Button1Click(Sender: TObject); procedure Button2Click(Sender: TObject); procedure Button3Click(Sender: TObject); procedure Button4Click(Sender: TObject); procedure Button5Click(Sender: TObject); procedure FormClose(Sender: TObject; var Action: TCloseAction); private hWndC : THandle; public { Public declarations } end; var Form1: TForm1; const WM_CAP_START = WM_USER; const WM_CAP_STOP = WM_CAP_START + 68; const WM_CAP_DRIVER_CONNECT = WM_CAP_START + 10; const WM_CAP_DRIVER_DISCONNECT = WM_CAP_START + 11; const WM_CAP_SAVEDIB = WM_CAP_START + 25; const WM_CAP_GRAB_FRAME = WM_CAP_START + 60; const WM_CAP_SEQUENCE = WM_CAP_START + 62; const WM_CAP_FILE_SET_CAPTURE_FILEA = WM_CAP_START + 20; const WM_CAP_SEQUENCE_NOFILE =WM_CAP_START+ 63 const WM_CAP_SET_OVERLAY =WM_CAP_START+ 51 const WM_CAP_SET_PREVIEW =WM_CAP_START+ 50 const WM_CAP_SET_CALLBACK_VIDEOSTREAM = WM_CAP_START +6; const WM_CAP_SET_CALLBACK_ERROR=WM_CAP_START +2; const WM_CAP_SET_CALLBACK_STATUSA= WM_CAP_START +3; const WM_CAP_SET_CALLBACK_FRAME= WM_CAP_START +5; const WM_CAP_SET_SCALE=WM_CAP_START+ 53 const WM_CAP_SET_PREVIEWRATE=WM_CAP_START+ 52 function capCreateCaptureWindowA(lpszWindowName : PCHAR; dwStyle : longint;x : integer;y : integer;nWidth : integer; nHeight : integer;ParentWin : HWND;nId : integer): HWND; STDCALL EXTERNAL 'AVICAP32.DLL'; implementation {$R *.dfm} procedure TForm1.Button1Click(Sender: TObject); begin hWndC := capCreateCaptureWindowA('My Own Capture Window',WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0); hWndC := capCreateCaptureWindowA('My Own Capture Window',WS_CHILD or WS_VISIBLE ,Panel1.Left,Panel1.Top,Panel1.Width,Panel1.Height,Form1.Handle,0); if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_SET_CALLBACK_VIDEOSTREAM, 0, 0); SendMessage(hWndC, WM_CAP_SET_CALLBACK_ERROR, 0, 0); SendMessage(hWndC, WM_CAP_SET_CALLBACK_STATUSA, 0, 0); SendMessage(hWndC, WM_CAP_DRIVER_CONNECT, 0, 0); SendMessage(hWndC, WM_CAP_SET_SCALE, 1, 0); SendMessage(hWndC, WM_CAP_SET_PREVIEWRATE, 66, 0); SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0); SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0); end; end; procedure TForm1.Button2Click(Sender: TObject); begin if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0); hWndC := 0; end; end; procedure TForm1.Button3Click(Sender: TObject); begin if hWndC <> 0 then begin SendMessage(hWndC,WM_CAP_SAVEDIB,0,longint(pchar('c:/test.bmp'))); end; end; procedure TForm1.Button4Click(Sender: TObject); begin if hWndC <> 0 then begin SendMessage(hWndC,WM_CAP_FILE_SET_CAPTURE_FILEA,0, Longint(pchar('c:/test.avi'))); SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0); end; end; procedure TForm1.Button5Click(Sender: TObject); begin if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_STOP, 0, 0); end; end; procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction); begin if hWndC <> 0 then begin SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0); end; end; end.

　
　如果電腦沒有網路攝影機，但又想看看程式的效果，可以嗎？

　　當然可以，找個虛擬網路攝影機不就搞定，大家可以試試SoftCam這個軟體，它
是一個名副其實的軟體攝像機，能類比成為“真實的”攝像機，提醒一下各位，大家可不要用這個東東用在QQ，MSN等聊天軟體上欺騙MM或GG啊。

　
　關於網路攝影機編程，大家也可以看看這組VCL組件：DSPack，DSPack是一套使用微軟Direct
Show和DirectX技術的類和組件，設計工作於DirectX 9，支援系統Win9X, ME, 2000和Windows XP。

　
　好了，就介紹這些了，至於視屏聊天怎麼實現，就看你的了，無非是把資料壓縮傳輸給對方，顯示出來，不過話又說回來，看似簡單，實現起來還有些難度的。