Как получить картинку с видео источника

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Panel1: TPanel;
    OpenVideo: TButton;
    CloseVideo: TButton;
    GrabFrame: TButton;
    SaveBMP: TButton;
    StartAVI: TButton;
    StopAVI: TButton;
    SaveDialog1: TSaveDialog;
    procedure FormCreate(Sender: TObject);
    procedure OpenVideoClick(Sender: TObject);
    procedure CloseVideoClick(Sender: TObject);
    procedure GrabFrameClick(Sender: TObject);
    procedure SaveBMPClick(Sender: TObject);
    procedure StartAVIClick(Sender: TObject);
    procedure StopAVIClick(Sender: TObject);
  private
    { Private declarations }
    hWndC: THandle;
    CapturingAVI: bool;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

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;

function capCreateCaptureWindowA(lpszWindowName: PCHAR;
  dwStyle: longint;
  x: integer;
  y: integer;
  nWidth: integer;
  nHeight: integer;
  ParentWin: HWND;
  nId: integer): HWND;
  stdcall external 'AVICAP32.DLL';

procedure TForm1.FormCreate(Sender: TObject);
begin
  CapturingAVI := false;
  hWndC := 0;
  SaveDialog1.Options :=
    [ofHideReadOnly, ofNoChangeDir, ofPathMustExist]
end;

procedure TForm1.OpenVideoClick(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_DRIVER_CONNECT, 0, 0);
end;

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

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

procedure TForm1.SaveBMPClick(Sender: TObject);
begin
  if hWndC <> 0 then
  begin
    SaveDialog1.DefaultExt := 'bmp';
    SaveDialog1.Filter := 'Bitmap files (*.bmp)|*.bmp';
    if SaveDialog1.Execute then
      SendMessage(hWndC,
        WM_CAP_SAVEDIB,
        0,
        longint(pchar(SaveDialog1.FileName)));
  end;
end;

procedure TForm1.StartAVIClick(Sender: TObject);
begin
  if hWndC <> 0 then
  begin
    SaveDialog1.DefaultExt := 'avi';
    SaveDialog1.Filter := 'AVI files (*.avi)|*.avi';
    if SaveDialog1.Execute then
    begin
      CapturingAVI := true;
      SendMessage(hWndC,
        WM_CAP_FILE_SET_CAPTURE_FILEA,
        0,
        Longint(pchar(SaveDialog1.FileName)));
      SendMessage(hWndC, WM_CAP_SEQUENCE, 0, 0);
    end;
  end;
end;

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

end.