unit1.pas

在delphi开发环境下基于vfw 的视频传输系统

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, IdBaseComponent, IdComponent,IdUDPBase,vfw, IdUDPClient, ExtCtrls,
  StdCtrls,jpeg;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Panel1: TPanel;
    IdUDPClient1: TIdUDPClient;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  CapWnd:THandle; //定义捕捉窗句柄
CapParms:TcaptureParms; //用于设置设备属性的结构变量
BMPINFO:TBitmapInfo; //BMP图像信息
implementation

{$R *.dfm}
//function
//FrameCallBack(hWnd:   HWND;   lpVHdr:   PVIDEOHDR):   LongInt;stdcall;

function FrameCallBack(hWnd: HWND; lpVHdr: PVIDEOHDR): DWORD;stdcall;
var hd:Thandle;
jpg:TJpegImage;
memStream :TMemoryStream;
Bitmap:TBitmap;
begin //将数据显在Image， 
Bitmap:=TBitmap.Create;
Bitmap.Width :=BMPINFO.bmiHeader.biWidth;
// New size of Bitmap 
Bitmap.Height:=BMPINFO.bmiHeader.biHeight; 
hd:= DrawDibOpen; 
DrawDibDraw(hd,Bitmap.canvas.handle,0,0,BMPINFO.BmiHeader.biwidth,BMPINFO.bmiheader.biheight,@BMPINFO.bmiHeader,lpVHdr^.lpData,0,0,BMPINFO.bmiHeader.biWidth,BMPINFO.bmiHeader.biheight,0);
DrawDibClose(hd);
//发送数据 
memStream := TMemoryStream.Create;
jpg := TJpegImage.Create; jpg.Assign(Bitmap);
jpg.CompressionQuality := 40; 
//jpg压缩质量 
jpg.JPEGNeeded; 
jpg.Compress;
jpg.SaveToStream(memStream);
jpg.Free;
//因为UDP数据包有大小限制，这里如果超出部分，就没有传输，完全可以发几次发出去
Form1.IdUDPClient1.BroadcastEnabled:=true;//用广播功能
if memStream.Size>Form1.IdUDPClient1.BufferSize then 
 //向192.168.0.X网段广播，端口 9001
 Form1.IdUDPClient1.SendBuffer('192.168.0.255',9001,memStream.Memory^,Form1.IdUDPClient1.BufferSize)
else
 Form1.IdUDPClient1.SendBuffer('192.168.0.255',9001,memStream.Memory^,memStream.Size);
 memStream.Free;
 Bitmap.Free;
end;


procedure TForm1.Button1Click(Sender: TObject);
begin
CapWnd   :=   capCreateCaptureWindow('我的窗口',   WS_VISIBLE   or   WS_CHILD,//窗口样式
          0,   //X坐标
          0,   //Y坐标   
          panel1.Width,   //窗口宽   
          panel1.Height,   //窗口高   
          panel1.handle,   //窗口句柄   
          0);   //通常为0   
          if   CapWnd   =   0   then   exit;   //定义帧捕捉回调函数   
       CapSetCallbackOnFrame(CapWnd,FrameCallBack);
         // CapSetCallbackOnFrame (ghCapWnd,LongInt(@VideoStreamCallBack));

          CapParms.dwRequestMicroSecPerFrame:=1;
          CapParms.fLimitEnabled:=FALSE;   
          CapParms.fCaptureAudio:=FALSE;   
          CapParms.fMCIControl:=FALSE;   
          CapParms.fYield:=TRUE;   
          CapParms.vKeyAbort:=VK_ESCAPE;   
          CapParms.fAbortLeftMouse:=False;   
          CapParms.fAbortRightMouse:=FALSE;   //让设置生效   
          CapCaptureSetSetup(capWnd,@CapParms,sizeof(TCAPTUREPARMS));   
          CapPreviewRate(capWnd,33);   //设置预览视频的频率   
          CapCaptureSequenceNoFile(capWnd);   //如果要捕捉视频流，则要使用函数来指定不生成文件，不然会自动生成AVI文件   
          CapDriverConnect(CapWnd,0);   //连接摄像头设备，第二个参数是个序号，当系统中装有多个显示驱动程序时，其值分别依次为0到总个数如果有多个摄像头，那么就是0->1->2
           capGetVideoFormat(capWnd,   @BMPINFO,sizeof(TBitmapInfo));   //取得视频图像数据头   
          CapPreviewScale(capWnd,TRUE);   //是否缩放
          CapOverlay(capWnd,true);   //指定是否使用叠加模式，true为使用，否则为false
          CapPreview(capWnd,true);
          end;


procedure TForm1.Button2Click(Sender: TObject);
begin
capCaptureAbort(CapWnd); //停止捕捉
capDriverDisconnect(CapWnd); //将捕捉窗同驱动器断开
end;

end.