Getting a snapshot from a webcam with Delphi - delphi

Question

I need to get a regular snapshot from a webcam in Delphi. Speed is not a problem (once a second is fine). I have tried demo code from based on stuff from http://delphi.pjh2.de but I can't get it to work. It compiles and runs OK but the callback function never fires.
I don't have a real webcam but am running instead a simulator. The simulator works (I can see the video using Skype) but not with the test app. I don't really know where to start looking...
Can anyone be bothered to try this code? (Apologies for the voluminous post - couldn't find how or if you can attach files - a zip file is available here.)
Alternatively, any webcam demo code would be appreciated, preferably with a known good EXE as well as source.
program WebCamTest;
uses
Forms,
WebCamMainForm in 'WebCamMainForm.pas' {Form1},
yuvconverts in 'yuvconverts.pas';
{$R *.res}
begin
Application.Initialize;
Application.CreateForm(TForm1, Form1);
Application.Run;
end.
unit WebCamMainForm;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs, ExtCtrls, YUVConverts, StdCtrls, JPeg {, TntStdCtrls} ;
const
WM_CAP_START = WM_USER;
WM_CAP_DRIVER_CONNECT = WM_CAP_START+ 10;
WM_CAP_SET_PREVIEW = WM_CAP_START+ 50;
WM_CAP_SET_OVERLAY = WM_CAP_START+ 51;
WM_CAP_SET_PREVIEWRATE = WM_CAP_START+ 52;
WM_CAP_GRAB_FRAME_NOSTOP = WM_CAP_START+ 61;
WM_CAP_SET_CALLBACK_FRAME = WM_CAP_START+ 5;
WM_CAP_GET_VIDEOFORMAT = WM_CAP_START+ 44;
WM_CAP_DLG_VIDEOFORMAT = WM_CAP_START+ 41;
PICWIDTH= 640;
PICHEIGHT= 480;
SUBLINEHEIGHT= 18;
EXTRAHEIGHT= 400;
type
TVIDEOHDR= record
lpData: Pointer; // address of video buffer
dwBufferLength: DWord; // size, in bytes, of the Data buffer
dwBytesUsed: DWord; // see below
dwTimeCaptured: DWord; // see below
dwUser: DWord; // user-specific data
dwFlags: DWord; // see below
dwReserved1, dwReserved2, dwReserved3: DWord; // reserved; do not use
end;
TVIDEOHDRPtr= ^TVideoHDR;
DWordDim= array[1..PICWIDTH] of DWord;
TForm1 = class(TForm)
Timer1: TTimer;
Panel1: TPanel;
procedure FormDestroy(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormActivate(Sender: TObject);
procedure Timer1Timer(Sender: TObject);
private
FCapHandle: THandle;
FCodec: TVideoCodec;
FBuf1, FBuf2: array[1..PICHEIGHT] of DWordDim;
FBitmap: TBitmap;
FJpeg: TJPegImage;
{ Private-Deklarationen }
public
{ Public-Deklarationen }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
function capCreateCaptureWindow(lpszWindowName: LPCSTR;
dwStyle: DWORD;
x, y,
nWidth,
nHeight: integer;
hwndParent: HWND;
nID: integer): HWND; stdcall;
external 'AVICAP32.DLL' name 'capCreateCaptureWindowA';
function FrameCallbackFunction(AHandle: hWnd; VIDEOHDR: TVideoHDRPtr): bool; stdcall;
var
I: integer;
begin
result:= true;
with form1 do begin
try
ConvertCodecToRGB(FCodec, VideoHDR^.lpData, #FBuf2, PICWIDTH, PICHEIGHT);
for I:= 1 to PICHEIGHT do FBuf1[I]:= FBuf2[PICHEIGHT- (I- 1)];
SetBitmapBits(FBitmap.Handle, PICWIDTH* PICHEIGHT* SizeOf(DWord), #FBuf1);
FBitmap.Canvas.Brush.Color:= clWhite;
FBitmap.Canvas.Font.Color:= clRed;
FJpeg.Assign(FBitmap);
FJpeg.CompressionQuality:= 85;
FJpeg.ProgressiveEncoding:= true;
FJpeg.SaveToFile('c:\webcam.jpg');
SendMessage(FCapHandle, WM_CAP_SET_CALLBACK_FRAME, 0, 0);
except
end;
end;
end;
//------------------------------------------------------------------------------
procedure TForm1.FormCreate(Sender: TObject);
var BitmapInfo: TBitmapInfo;
begin
Timer1.Enabled := false;
FBitmap:= TBitmap.Create;
FBitmap.Width:= PICWIDTH;
FBitmap.Height:= PICHEIGHT+ SUBLINEHEIGHT+ EXTRAHEIGHT;
FBitmap.PixelFormat:= pf32Bit;
FBitmap.Canvas.Font.Assign(Panel1.Font);
FBitmap.Canvas.Brush.Style:= bssolid;
FBitmap.Canvas.Rectangle(0, PICHEIGHT, PICWIDTH, PICHEIGHT+ SUBLINEHEIGHT);
FJpeg:= TJpegImage.Create;
FCapHandle:= capCreateCaptureWindow('Video', WS_CHILD or WS_VISIBLE, 0, 0, PICWIDTH, PICHEIGHT, Panel1.Handle, 1);
SendMessage(FCapHandle, WM_CAP_DRIVER_CONNECT, 0, 0);
SendMessage(FCapHandle, WM_CAP_SET_PREVIEWRATE, 15000, 0);
sendMessage(FCapHandle, WM_CAP_SET_OVERLAY, 1, 0);
SendMessage(FCapHandle, WM_CAP_SET_PREVIEW, 1, 0);
// SendMessage(FCapHandle, WM_CAP_DLG_VIDEOFORMAT,1,0); // -this was commented out
FillChar(BitmapInfo, SizeOf(BitmapInfo), 0);
SendMessage(FCapHandle, WM_CAP_GET_VIDEOFORMAT, SizeOf(BitmapInfo), Integer(#BitmapInfo));
FCodec:= BICompressionToVideoCodec(bitmapinfo.bmiHeader.biCompression);
if FCodec<> vcUnknown then begin
Timer1.Enabled:= true;
end;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FBitmap.Free;
FJpeg.Free;
end;
procedure TForm1.FormActivate(Sender: TObject);
begin
if FCodec= vcUnknown then
showMessage('unknown compression');
FBitmap.Height:= PICHEIGHT+ SUBLINEHEIGHT;
end;
//------------------------------------------------------------------------------
procedure TForm1.Timer1Timer(Sender: TObject);
begin
SendMessage(FCapHandle, WM_CAP_SET_CALLBACK_FRAME, 0, integer(#FrameCallbackFunction));
SendMessage(FCapHandle, WM_CAP_GRAB_FRAME_NOSTOP, 1, 0); // ist hintergrundlauff盲hig
end;
end.
object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 301
ClientWidth = 562
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
OnActivate = FormActivate
OnCreate = FormCreate
OnDestroy = FormDestroy
PixelsPerInch = 96
TextHeight = 13
object Panel1: TPanel
Left = 48
Top = 16
Width = 185
Height = 145
Caption = 'Panel1'
TabOrder = 0
end
object Timer1: TTimer
OnTimer = Timer1Timer
Left = 464
Top = 24
end
end
{**************************************************************************************************}
{ }
{ YUVConverts }
{ }
{ The contents of this file are subject to the Y Library Public License Version 1.0 (the }
{ "License"); you may not use this file except in compliance with the License. You may obtain a }
{ copy of the License at http://delphi.pjh2.de/ }
{ }
{ Software distributed under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF }
{ ANY KIND, either express or implied. See the License for the specific language governing }
{ rights and limitations under the License. }
{ }
{ The Original Code is: YUVConverts.pas, part of CapDemoC.dpr. }
{ The Initial Developer of the Original Code is Peter J. Haas (libs#pjh2.de). Portions created }
{ by Peter J. Haas are Copyright (C) 2000-2005 Peter J. Haas. All Rights Reserved. }
{ }
{ Contributor(s): }
{ }
{ You may retrieve the latest version of this file at the homepage of Peter J. Haas, located at }
{ http://delphi.pjh2.de/ }
{ }
{**************************************************************************************************}
// For history see end of file
{$ALIGN ON, $BOOLEVAL OFF, $LONGSTRINGS ON, $IOCHECKS ON, $WRITEABLECONST OFF, $OVERFLOWCHECKS OFF}
{$RANGECHECKS OFF, $TYPEDADDRESS ON, $MINENUMSIZE 1}
unit yuvconverts;
interface
uses
Windows;
type
TVideoCodec = (vcUnknown, vcRGB, vcYUY2, vcUYVY, vcBTYUV, vcYVU9, vcYUV12, vcY8, vcY211);
const
BI_YUY2 = $32595559; // 'YUY2'
BI_UYVY = $59565955; // 'UYVY'
BI_BTYUV = $50313459; // 'Y41P'
BI_YVU9 = $39555659; // 'YVU9' planar
BI_YUV12 = $30323449; // 'I420' planar
BI_Y8 = $20203859; // 'Y8 '
BI_Y211 = $31313259; // 'Y211'
function BICompressionToVideoCodec(Value: DWord): TVideoCodec;
function ConvertCodecToRGB(Codec: TVideoCodec; Src, Dst: Pointer; AWidth, AHeight: Integer): Boolean;
implementation
function BICompressionToVideoCodec(Value: DWord): TVideoCodec;
begin
case Value of
BI_RGB, BI_BITFIELDS: Result := vcRGB; // no RLE
BI_YUY2: Result := vcYUY2 ;
BI_UYVY: Result := vcUYVY ;
BI_BTYUV: Result := vcBTYUV;
BI_YVU9: Result := vcYVU9;
BI_YUV12: Result := vcYUV12;
BI_Y8: Result := vcY8;
BI_Y211: Result := vcY211;
else
Result := vcUnknown;
end;
end;
const
// RGB255 ColorFAQ
fY = 298.082 / 256;
fRU = 0;
fGU = -100.291 / 256;
fBU = 516.411 / 256;
fRV = 408.583 / 256;
fGV = -208.120 / 256;
fBV = 0;
{ // RGB219 ColorFAQ too dark
fY = 256 / 256;
fRU = 0;
fGU = -86.132 / 256;
fBU = 443.506 / 256;
fRV = 350.901 / 256;
fGV = -178.738 / 256;
fBV = 0; }
{ // Earl same like RGB255
fY = 1.164;
fRU = 0;
fGU = -0.392;
fBU = 2.017;
fRV = 1.596;
fGV = -0.813;
fBV = 0;
}
// |R| |fY fRU fRV| |Y| | 16|
// |G| = |fY fGU fGV| * |U| - |128|
// |B| |fY fBU fBV| |V| |128|
type
TYUV = packed record
Y, U, V, F1: Byte;
end;
PBGR32 = ^TBGR32;
TBGR32 = packed record
B, G, R, A: Byte;
end;
function YUVtoBGRAPixel(AYUV: DWord): DWord;
var
ValueY, ValueU, ValueV: Integer;
ValueB, ValueG, ValueR: Integer;
begin
ValueY := TYUV(AYUV).Y - 16;
ValueU := TYUV(AYUV).U - 128;
ValueV := TYUV(AYUV).V - 128;
ValueB := Trunc(fY * ValueY + fBU * ValueU); // fBV = 0
if ValueB > 255 then
ValueB := 255;
if ValueB < 0 then
ValueB := 0;
ValueG := Trunc(fY * ValueY + fGU * ValueU + fGV * ValueV);
if ValueG > 255 then
ValueG := 255;
if ValueG < 0 then
ValueG := 0;
ValueR := Trunc(fY * ValueY + fRV * ValueV); // fRU = 0
if ValueR > 255 then
ValueR := 255;
if ValueR < 0 then
ValueR := 0;
with TBGR32(Result) do begin
B := ValueB;
G := ValueG;
R := ValueR;
A := 0;
end;
end;
type
TDWordRec = packed record
case Integer of
0: (B0, B1, B2, B3: Byte);
1: (W0, W1: Word);
end;
// UYVY
// YUV 4:2:2 (Y sample at every pixel, U and V sampled at every second pixel
// horizontally on each line). A macropixel contains 2 pixels in 1 DWord.
// 16 Bits per Pixel, 4 Byte Macropixel
// U0 Y0 V0 Y1
procedure UYVYtoRGB(Src, Dst: Pointer; AWidth, AHeight: Integer);
type
PUYVY = ^TUYVY;
TUYVY = packed record
U, Y0, V, Y1: Byte;
end;
var
x, y: Integer;
w: Integer;
SrcPtr: PDWord;
DstPtr: PDWord;
SrcLineSize: Integer;
DstLineSize: Integer;
YUV: DWord;
b: Byte;
begin
SrcLineSize := AWidth * 2;
DstLineSize := AWidth * 4;
// Dst is Bottom Top Bitmap
Inc(PByte(Dst), (AHeight - 1) * DstLineSize);
w := (AWidth div 2) - 1; { TODO : bei ungeraden Breiten fehlt letztes Pixel }
for y := 0 to AHeight - 1 do begin
SrcPtr := Src;
DstPtr := Dst;
for x := 0 to w do begin
YUV := SrcPtr^;
// First Pixel
b := TDWordRec(YUV).B0;
TDWordRec(YUV).B0 := TDWordRec(YUV).B1;
TDWordRec(YUV).B1 := b;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
// Second Pixel
TDWordRec(YUV).B0 := TDWordRec(YUV).B3;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Inc(SrcPtr);
end;
Dec(PByte(Dst), DstLineSize);
Inc(PByte(Src), SrcLineSize);
end;
end;
// YUY2, YUNV, V422
// YUV 4:2:2 as for UYVY but with different component ordering within the DWord
// macropixel.
// 16 Bits per Pixel, 4 Byte Macropixel
// Y0 U0 Y1 V0
procedure YUY2toRGB(Src, Dst: Pointer; AWidth, AHeight: Integer);
var
x, y: Integer;
w: Integer;
SrcPtr: PDWord;
DstPtr: PDWord;
SrcLineSize: Integer;
DstLineSize: Integer;
YUV: DWord;
b: Byte;
begin
SrcLineSize := AWidth * 2;
DstLineSize := AWidth * 4;
// Dst is Bottom Top Bitmap
Inc(PByte(Dst), (AHeight - 1) * DstLineSize);
w := (AWidth div 2) - 1; { TODO : bei ungeraden Breiten fehlt letztes Pixel }
for y := 0 to AHeight - 1 do begin
SrcPtr := Src;
DstPtr := Dst;
for x := 0 to w do begin
YUV := SrcPtr^;
// First Pixel
b := TDWordRec(YUV).B2; // Y0 U Y1 V -> Y0 U V Y1
TDWordRec(YUV).B2 := TDWordRec(YUV).B3;
TDWordRec(YUV).B3 := b;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
// Second Pixel
TDWordRec(YUV).B0 := TDWordRec(YUV).B3;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Inc(SrcPtr);
end;
Dec(PByte(Dst), DstLineSize);
Inc(PByte(Src), SrcLineSize);
end;
end;
// BTYUV, I42P
// YUV 4:1:1 (Y sample at every pixel, U and V sampled at every fourth pixel
// horizontally on each line). A macropixel contains 8 pixels in 3 DWords.
// 16 Bits per Pixel, 12 Byte Macropixel
// U0 Y0 V0 Y1 U4 Y2 V4 Y3 Y4 Y5 Y6 Y7
procedure BTYUVtoRGB(Src, Dst: Pointer; AWidth, AHeight: Integer);
type
PBTYUVPixel = ^TBTYUVPixel;
TBTYUVPixel = packed record
U0, Y0, V0, Y1, U4, Y2, V4, Y3, Y4, Y5, Y6, Y7: Byte;
end;
var
x, y: Integer;
w: Integer;
SrcPtr: PBTYUVPixel;
DstPtr: PDWord;
SrcLineSize: Integer;
DstLineSize: Integer;
YUV: DWord;
SrcPixel: TBTYUVPixel;
begin
SrcLineSize := ((AWidth + 7) div 8) * (3 * 4);
DstLineSize := AWidth * 4;
w := AWidth - 1;
for y := 0 to AHeight - 1 do begin
SrcPtr := Src;
DstPtr := Dst;
x := w;
while x > 0 do begin
// read macropixel
SrcPixel := SrcPtr^;
// First 4 Pixel
TYUV(YUV).U := SrcPixel.U0;
TYUV(YUV).V := SrcPixel.V0;
TYUV(YUV).Y := SrcPixel.Y0;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
TYUV(YUV).Y := SrcPixel.Y1;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
TYUV(YUV).Y := SrcPixel.Y2;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
TYUV(YUV).Y := SrcPixel.Y3;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
// Second 4 Pixel
TYUV(YUV).U := SrcPixel.U4;
TYUV(YUV).V := SrcPixel.V4;
TYUV(YUV).Y := SrcPixel.Y4;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
TYUV(YUV).Y := SrcPixel.Y5;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
TYUV(YUV).Y := SrcPixel.Y6;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Dec(x);
if x <= 0 then
Break;
TYUV(YUV).Y := SrcPixel.Y7;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Inc(SrcPtr);
end;
Inc(PByte(Dst), DstLineSize);
Inc(PByte(Src), SrcLineSize);
end;
end;
// YVU9
// 8 bit Y plane followed by 8 bit 4x4 subsampled V and U planes.
// 9 Bits per Pixel, planar format
procedure YVU9toRGB(Src, Dst: Pointer; AWidth, AHeight: Integer);
var
x, y, r, l: Integer;
w: Integer;
SrcYPtr: PByte;
SrcUPtr: PByte;
SrcVPtr: PByte;
DstPtr: PDWord;
SrcYLineSize: Integer;
SrcUVLineSize: Integer;
DstLineSize: Integer;
YUV: DWord;
begin
DstLineSize := AWidth * 4;
SrcYLineSize := AWidth;
SrcUVLineSize := (AWidth + 3) div 4;
// Dst is Bottom Top Bitmap
Inc(PByte(Dst), (AHeight - 1) * DstLineSize);
SrcYPtr := Src;
SrcVPtr := PByte(LongInt(SrcYPtr) + SrcYLineSize * AHeight);
SrcUPtr := PByte(LongInt(SrcVPtr) + SrcUVLineSize * ((AHeight + 3) div 4));
w := (AWidth div 4) - 1; { TODO : bei ungeraden Breiten fehlt letztes Pixel }
for y := 0 to (AHeight div 4) - 1 do begin { TODO : bei ungeraden H枚hen fehlt letzte Reihe }
for l := 0 to 3 do begin
DstPtr := Dst;
for x := 0 to w do begin
// U and V
YUV := (SrcUPtr^ shl 8) or (SrcVPtr^ shl 16);
for r := 0 to 3 do begin
YUV := (YUV and $00FFFF00) or SrcYPtr^;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Inc(SrcYPtr);
end;
Inc(SrcUPtr);
Inc(SrcVPtr);
end;
Dec(PByte(Dst), DstLineSize);
if l < 3 then begin
Dec(SrcUPtr, SrcUVLineSize);
Dec(SrcVPtr, SrcUVLineSize);
end;
end;
end;
end;
// YUV12, I420, IYUV
// 8 bit Y plane followed by 8 bit 2x2 subsampled U and V planes.
// 12 Bits per Pixel, planar format
procedure YUV12toRGB(Src, Dst: Pointer; AWidth, AHeight: Integer); // I420, IYUV
var
x, y, l: Integer;
w: Integer;
SrcYPtr: PByte;
SrcUPtr: PByte;
SrcVPtr: PByte;
DstPtr: PDWord;
SrcYLineSize: Integer;
SrcUVLineSize: Integer;
DstLineSize: Integer;
YUV: DWord;
begin
DstLineSize := AWidth * 4;
SrcYLineSize := AWidth;
SrcUVLineSize := (AWidth + 1) div 2;
// Dst is Bottom Top Bitmap
Inc(PByte(Dst), (AHeight - 1) * DstLineSize);
SrcYPtr := Src;
SrcUPtr := PByte(LongInt(SrcYPtr) + SrcYLineSize * AHeight);
SrcVPtr := PByte(LongInt(SrcUPtr) + SrcUVLineSize * ((AHeight + 1) div 2));
w := (AWidth div 2) - 1; { TODO : bei ungeraden Breiten fehlt letztes Pixel }
for y := 0 to (AHeight div 2) - 1 do begin { TODO : bei ungeraden H枚hen fehlt letzte Reihe }
for l := 0 to 1 do begin
DstPtr := Dst;
for x := 0 to w do begin
// First Pixel
YUV := SrcYPtr^ or (SrcUPtr^ shl 8) or (SrcVPtr^ shl 16);
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Inc(SrcYPtr);
// Second Pixel
YUV := (YUV and $00FFFF00) or SrcYPtr^;
DstPtr^ := YUVtoBGRAPixel(YUV);
Inc(DstPtr);
Inc(SrcYPtr);
Inc(SrcUPtr);
Inc(SrcVPtr);
end;
Dec(PByte(Dst), DstLineSize);
if l = 0 then begin
Dec(SrcUPtr, SrcUVLineSize);
Dec(SrcVPtr, SrcUVLineSize);
end;
end;
end;
end;
// Y8, Y800
// Simple, single Y plane for monochrome images.
// 8 Bits per Pixel, planar format
procedure Y8toRGB(Src, Dst: Pointer; AWidth, AHeight: Integer);
var
x, y: Integer;
w: Integer;
SrcPtr: PByte;
DstPtr: PDWord;
SrcLineSize: Integer;
DstLineSize: Integer;
Pixel: DWord;
begin
SrcLineSize := AWidth;
DstLineSize := AWidth * 4;
// Dst is Bottom Top Bitmap
Inc(PByte(Dst), (AHeight - 1) * DstLineSize);
w := (AWidth) - 1;
for y := 0 to AHeight - 1 do begin
SrcPtr := Src;
DstPtr := Dst;
for x := 0 to w do begin
Pixel := SrcPtr^;
TDWordRec(Pixel).B1 := TDWordRec(Pixel).B0;
TDWordRec(Pixel).B2 := TDWordRec(Pixel).B0;
TDWordRec(Pixel).B3 := 0;
DstPtr^ := Pixel;
Inc(DstPtr);
Inc(SrcPtr);
end;
Dec(PByte(Dst), DstLineSize);
Inc(PByte(Src), SrcLineSize);
end;
end;
// Y211
// Packed YUV format with Y sampled at every second pixel across each line
// and U and V sampled at every fourth pixel.
// 8 Bits per Pixel, 4 Byte Macropixel
// Y0, U0, Y2, V0
procedure Y211toRGB(Src, Dst: Pointer; AWidth, AHeight: Integer);
type
PYUYV = ^TYUYV;
TYUYV = packed record
Y0, U, Y2, V: Byte;
end;
var
x, y: Integer;
w : Integer;
SrcPtr : PDWord;
DstPtr : PDWord;
SrcLineSize : Integer;
DstLineSize : Integer;
YUV: DWord;
BGR: DWord;
b: Byte;
begin
SrcLineSize := ((AWidth + 3) div 4) * 4;
DstLineSize := AWidth * 4;
// Dst is Bottom Top Bitmap
Inc(PByte(Dst), (AHeight - 1) * DstLineSize);
w := (AWidth div 4) - 1; { TODO : bei ungeraden Breiten fehlt letztes Pixel }
for y := 0 to AHeight - 1 do begin
SrcPtr := Src;
DstPtr := Dst;
for x := 0 to w do begin
// Y0 U Y2 V
YUV := SrcPtr^;
// First and second Pixel
b := TDWordRec(YUV).B2; // Y0 U Y2 V -> Y0 U V Y2
TDWordRec(YUV).B2 := TDWordRec(YUV).B3;
TDWordRec(YUV).B3 := b;
BGR := YUVtoBGRAPixel(YUV);
DstPtr^ := BGR;
Inc(DstPtr);
DstPtr^ := BGR;
Inc(DstPtr);
// third and fourth
TDWordRec(YUV).B0 := TDWordRec(YUV).B3; // Y0 U V Y2 -> Y2 U V Y2
BGR := YUVtoBGRAPixel(YUV);
DstPtr^ := BGR;
Inc(DstPtr);
DstPtr^ := BGR;
Inc(DstPtr);
Inc(SrcPtr);
end;
Dec(PByte(Dst), DstLineSize);
Inc(PByte(Src), SrcLineSize);
end;
end;
function ConvertCodecToRGB(Codec: TVideoCodec; Src, Dst: Pointer; AWidth, AHeight: Integer): Boolean;
begin
Result := True;
case Codec of
vcYUY2: YUY2toRGB (Src, Dst, AWidth, AHeight);
vcUYVY: UYVYtoRGB (Src, Dst, AWidth, AHeight);
vcBTYUV: BTYUVtoRGB(Src, Dst, AWidth, AHeight);
vcYVU9: YVU9toRGB (Src, Dst, AWidth, AHeight);
vcYUV12: YUV12toRGB(Src, Dst, AWidth, AHeight);
vcY8: Y8toRGB (Src, Dst, AWidth, AHeight);
vcY211: Y211toRGB (Src, Dst, AWidth, AHeight);
else
Result := False;
end;
end;
// History:
// 2005-02-12, Peter J. Haas
//
// 2002-02-22, Peter J. Haas
// - add YVU9, YUV12 (I420)
// - add Y211 (untested)
//
// 2001-06-14, Peter J. Haas
// - First public version
// - YUY2, UYVY, BTYUV (Y41P), Y8
end.
Some message results:
var
MsgResult : Integer ;
procedure TForm1.FormCreate(Sender: TObject);
var BitmapInfo: TBitmapInfo;
begin
Timer1.Enabled := false;
FBitmap:= TBitmap.Create;
FBitmap.Width:= PICWIDTH;
FBitmap.Height:= PICHEIGHT+ SUBLINEHEIGHT+ EXTRAHEIGHT;
FBitmap.PixelFormat:= pf32Bit;
FBitmap.Canvas.Font.Assign(Panel1.Font);
FBitmap.Canvas.Brush.Style:= bssolid;
FBitmap.Canvas.Rectangle(0, PICHEIGHT, PICWIDTH, PICHEIGHT+ SUBLINEHEIGHT);
FJpeg:= TJpegImage.Create;
FCapHandle:= capCreateCaptureWindow('Video', WS_CHILD or WS_VISIBLE, 0, 0, PICWIDTH, PICHEIGHT, Panel1.Handle, 1); // returns 2558326
MsgResult := SendMessage(FCapHandle, WM_CAP_DRIVER_CONNECT, 0, 0); // returns 0
MsgResult := SendMessage(FCapHandle, WM_CAP_SET_PREVIEWRATE, 15000, 0); // returns 1
MsgResult := sendMessage(FCapHandle, WM_CAP_SET_OVERLAY, 1, 0); // returns 0
MsgResult := SendMessage(FCapHandle, WM_CAP_SET_PREVIEW, 1, 0); // returns 0
// SendMessage(FCapHandle, WM_CAP_DLG_VIDEOFORMAT,1,0); // -this was commented out
FillChar(BitmapInfo, SizeOf(BitmapInfo), 0);
MsgResult := SendMessage(FCapHandle, WM_CAP_GET_VIDEOFORMAT, SizeOf(BitmapInfo), Integer(#BitmapInfo)); // returns 0
FCodec:= BICompressionToVideoCodec(bitmapinfo.bmiHeader.biCompression); // returns vcRGB
if FCodec<> vcUnknown then begin
Timer1.Enabled:= true;
end;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
FBitmap.Free;
FJpeg.Free;
end;
procedure TForm1.FormActivate(Sender: TObject);
begin
if FCodec= vcUnknown then
showMessage('unknown compression');
FBitmap.Height:= PICHEIGHT+ SUBLINEHEIGHT;
end;
//------------------------------------------------------------------------------
procedure TForm1.Timer1Timer(Sender: TObject);
begin
MsgResult := SendMessage(FCapHandle, WM_CAP_SET_CALLBACK_FRAME, 0, integer(#FrameCallbackFunction)); // returns 0
MsgResult := SendMessage(FCapHandle, WM_CAP_GRAB_FRAME_NOSTOP, 1, 0); // ist hintergrundlauff盲hig // returns 0
end;

Answer 1

Your program works for me on Win7 32bits with D2010.
What it does though is raising an exception:
---------------------------
Project WebCamTest.exe raised exception class EFCreateError with message
'Cannot create file "c:\webcam.jpg". Access is denied'.
---------------------------
which can be corrected by changing
FJpeg.SaveToFile('c:\webcam.jpg');
to
FJpeg.SaveToFile(TPath.GetTempPath + '\webcam.jpg');
And also, it does not display the whole available image, you'd have to enlarge your Panel, recenter or shrink the webcam output.
Update with some code modifications that would make it work per your comments...
// introducing the RGB array and a buffer
TVideoArray = array[1..PICHEIGHT] of array[1..PICWIDTH] of TRGBTriple;
PVideoArray = ^TVideoArray;
TForm1 = class(TForm)
[...]
FBuf24_1: TVideoArray;
[...]
function FrameCallbackFunction(AHandle: hWnd; VIDEOHDR: TVideoHDRPtr): bool; stdcall;
var
I: integer;
begin
result:= true;
with form1 do begin
try
if ConvertCodecToRGB(FCodec, VideoHDR^.lpData, #FBuf2, PICWIDTH, PICHEIGHT) then
begin
for I:= 1 to PICHEIGHT do FBuf1[I]:= FBuf2[PICHEIGHT- (I- 1)];
SetBitmapBits(FBitmap.Handle, PICWIDTH* PICHEIGHT* SizeOf(DWord), #FBuf1);
end
else
begin // assume RGB
for I:= 1 to PICHEIGHT do
FBuf24_1[I] := PVideoArray(VideoHDR^.lpData)^[PICHEIGHT-I+1];
SetBitmapBits(FBitmap.Handle, PICWIDTH* PICHEIGHT* SizeOf(RGBTriple), #FBuf24_1);
end;
[...]

Answer 2

If you wish to use DirectX API instead of deprecated Video For Windows (VFW) API:
http://www.delphibasics.info/home/delphibasicsprojects/directxdelphiwebcamcaptureexample
Here is a link to a larger project implementing the code detailed below:
http://www.delphibasics.info/home/delphibasicssnippets/delphiwebcamcaptureexample
Interchange lines indicated by comment notation as you wish.
program WebcamTest;
//www.delphibasics.info
//cswi
uses
Windows;
const
WM_CAP_DRIVER_CONNECT = 1034;
WM_CAP_GRAB_FRAME = 1084;
//WM_CAP_SAVEDIB = 1049;
WM_CAP_EDIT_COPY = 1054;//
WM_CAP_DRIVER_DISCONNECT = 1035;
function SendMessageA(hWnd: Integer;
Msg: Integer;
wParam: Integer;
lParam: Integer): Integer;
stdcall;
external 'user32.dll' name 'SendMessageA';
function capGetDriverDescriptionA(DrvIndex: Cardinal;
Name: PAnsiChar;
NameLen: Integer;
Description: PAnsiChar;
DescLen: Integer) : Boolean;
stdcall;
external 'avicap32.dll' name 'capGetDriverDescriptionA';
function capCreateCaptureWindowA(lpszWindowName: PAnsiChar;
dwStyle: Integer;
x : Integer;
y : Integer;
nWidth : Integer;
nHeight : Integer;
ParentWin: Integer;
nId: Integer): Integer;
stdcall;
external 'avicap32.dll' name 'capCreateCaptureWindowA';
function IntToStr(i: Integer): String;
begin
Str(i, Result);
end;
var
WebCamId : Integer;
CaptureWindow : Integer;
x : Integer;
FileName : PAnsiChar;
hData: DWORD;
pData: Pointer;
dwSize: DWORD;
szText : AnsiString;
FileHandle, BytesWritten : LongWord;
begin
WebcamId := 0;
CaptureWindow := capCreateCaptureWindowA('CaptureWindow', 0, 0, 0, 0, 0, 0, 0);
if CaptureWindow <> 0 then
begin
if SendMessageA(CaptureWindow, WM_CAP_DRIVER_CONNECT, WebCamId, 0) <> 1 then
begin
SendMessageA(CaptureWindow, WM_CAP_DRIVER_DISCONNECT, 0, 0);
end
else
begin
for x := 1 to 20 do // Take 20 photos.
begin
SendMessageA(CaptureWindow, WM_CAP_GRAB_FRAME, 0, 0);
FileName := PAnsiChar('C:\Test' + IntToStr(x) + '.bmp');
//SendMessageA(CaptureWindow, WM_CAP_SAVEDIB, 0, LongInt(FileName));
SendMessageA(CaptureWindow, WM_CAP_EDIT_COPY, 0, LongInt(FileName));//
if OpenClipBoard(0) then
begin
hData := GetClipBoardData(CF_DIB);
if hData <> 0 then
begin
pData := GlobalLock(hData);
if pData <> nil then
begin
dwSize := GlobalSize(hData);
if dwSize <> 0 then
begin
FileHandle := CreateFileA(FileName, GENERIC_WRITE, FILE_SHARE_WRITE, nil, CREATE_NEW, FILE_ATTRIBUTE_HIDDEN, 0);
WriteFile(FileHandle, pData, dwSize, BytesWritten, nil);
CloseHandle(FileHandle);
end;
GlobalUnlock(DWORD(pData));
end;
end;
CloseClipBoard;
end;
end;
end;
SendMessageA(CaptureWindow, WM_CAP_DRIVER_DISCONNECT, 0, 0);
end;
end.

Answer 3

I use a component called TVideoCap. It is for 3, 4, and 5 but it includes source so it is easy to update. It will do exactly what you want. Just do a search for 'TVideoCap'.