Delphi 控制摄像头操作

DELPHI控制摄像头操作可以使用TVideoCap控件，或直接使用MS的AVICAP32.DLL就可轻松的实现对摄像头编程。

首先常量定义和函数定义：

implementation
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';
{$R *.dfm}

打开Delphi，添加Panel1到Form1上，定义一个全局变量，var hWndC : THandle; 添加button1 ，caption为激活摄像头：

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);
if hWndC <> 0 then
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_SEQUENCE_NOFILE, 1, 0);
SendMessage(hWndC, WM_CAP_SET_OVERLAY, 1, 0);
SendMessage(hWndC, WM_CAP_SET_PREVIEW, 1, 0);
end;

添加button2 ，caption为关闭摄像头：

procedure TForm1.Button2Click(Sender: TObject);
begin
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_DRIVER_DISCONNECT, 0, 0);
hWndC := 0;
end;
end;

添加button3 ，caption为保存为BMP图像：

procedure TForm1.Button3Click(Sender: TObject);
begin
if hWndC <> 0 then begin
SendMessage(hWndC,WM_CAP_SAVEDIB,0,longint(pchar('c:\\test.bmp')));
end;
end;

添加button4 ，caption为开始录像：

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;

添加button5 ，caption为停止录像：

procedure TForm1.Button5Click(Sender: TObject);
begin
if hWndC <> 0 then begin
SendMessage(hWndC, WM_CAP_STOP, 0, 0);
end;
end;

添加button6，caption为退出：

procedure TForm1.Button6Click(Sender: TObject);
begin
close;
end;

可以添加MediaPlayer和opendialog控件

添加button7，caption为加载视频：

procedure TForm1.Button7Click(Sender: TObject);
begin
openDialog1.DefaultExt := 'avi';
openDialog1.Filter := 'avi files (*.avi)|*.avi';

if OpenDialog1.Execute then
begin
if (MediaPlayer1.DeviceID<>0) then
begin
if (MediaPlayer1.Mode=mpplaying) then MediaPlayer1.Stop;
end;

MediaPlayer1.FileName:=openDialog1.FileName;
//MediaPlayer1.DisplayRect.Top:=panel2.Top;
//MediaPlayer1.DisplayRect.Left:=panel2.left;
//MediaPlayer1.DisplayRect.Right:=panel2.Height;
//MediaPlayer1.DeviceType :=dtAutoSelect;
Mediaplayer1.Open;
MediaPlayer1.Play;
end;
end;

如果电脑没有摄像头，panel就会黑黑的，可以尝试安装SoftCam虚拟摄像头。

关于摄像头编程，大家也可以看看这组VCL组件：DSPack，DSPack是一套使用微软Direct Show和DirectX技术的类和组件，设计工作于DirectX 9，支持系统Win9X, ME, 2000和Windows XP。

视屏聊天按数据压缩传输给对方，显示出来，不是那么简单。

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls, MPlayer;

type
TForm1 = class(TForm)
    Button1: TButton;
    Panel1: TPanel;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    Button6: TButton;
    Button7: TButton;
    OpenDialog1: TOpenDialog;
    MediaPlayer1: TMediaPlayer;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button7Click(Sender: TObject);
    procedure Button6Click(Sender: TObject);
private

{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
hWndC : THandle;