[C++] Win32 WebCam Video Function

[Uni Git]

First of all, I would like to credit snoopy11 for the original source code of which is found here: [url]http://www.dreamincode.net/forums/topic/193519-win32-webcam-program/[/url].

I am looking to add a function to this application for taking videos. A picture function has already been constructed as follows:

[cpp]
//Grab a Frame
SendMessage(camhwnd, WM_CAP_GRAB_FRAME, 0, 0);
//Copy the frame we have just grabbed to the clipboard
SendMessage(camhwnd, WM_CAP_EDIT_COPY,0,0);

//Copy the clipboard image data to a HBITMAP object called hbm
hdc = BeginPaint(camhwnd, &ps);
hdcMem = CreateCompatibleDC(hdc);
if (hdcMem != NULL)
{
if (OpenClipboard(camhwnd))
{
hbm = (HBITMAP) GetClipboardData(CF_BITMAP);
SelectObject(hdcMem, hbm);
GetClientRect(camhwnd, &rc);
CloseClipboard();
}
}
//Save hbm to a .bmp file called Frame.bmp
PBITMAPINFO pbi = CreateBitmapInfoStruct(hwnd, hbm);
CreateBMPFile(hwnd, "Frame.bmp", pbi, hbm, hdcMem);

SendMessage(camhwnd,WM_CAP_DRIVER_CONNECT,0,0);
SendMessage(camhwnd, WM_CAP_SET_SCALE, true , 0);
SendMessage(camhwnd, WM_CAP_SET_PREVIEWRATE, 66, 0);
SendMessage(camhwnd, WM_CAP_SET_PREVIEW, true , 0);
[/cpp]

With CreateBMPFile() and CreateBitmapInfoStruct() defined as follows:

[cpp]
void CreateBMPFile(HWND hwnd, LPTSTR pszFile, PBITMAPINFO pbi, HBITMAP hBMP, HDC hDC) {
HANDLE hf; // file handle
BITMAPFILEHEADER hdr; // bitmap file-header
PBITMAPINFOHEADER pbih; // bitmap info-header
LPBYTE lpBits; // memory pointer
DWORD dwTotal; // total count of bytes
DWORD cb; // incremental count of bytes
BYTE *hp; // byte pointer
DWORD dwTmp;

pbih = (PBITMAPINFOHEADER)pbi;
lpBits = (LPBYTE)GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);

if (!lpBits)
MessageBox(hwnd, TEXT("GlobalAlloc"), TEXT("Error"), MB_OK);

// Retrieve the color table (RGBQUAD array) and the bits (array of palette indices) from the DIB
if (!GetDIBits(hDC, hBMP, 0, (WORD)pbih->biHeight, lpBits, pbi, DIB_RGB_COLORS))
MessageBox(hwnd, TEXT("GetDIBits"), TEXT("Error"), MB_OK);

// Create the .BMP file.
hf = CreateFile(pszFile, GENERIC_READ | GENERIC_WRITE, (DWORD)0, NULL,
CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, (HANDLE)NULL);
if (hf == INVALID_HANDLE_VALUE)
MessageBox(hwnd, TEXT("CreateFile"), TEXT("Error"), MB_OK);

hdr.bfType = 0x4d42; // File type designator "BM" 0x42 = "B" 0x4d = "M"

// Compute the size of the entire file.
hdr.bfSize = (DWORD)(sizeof(BITMAPFILEHEADER)+pbih->biSize + pbih->biClrUsed * sizeof(RGBQUAD)+pbih->biSizeImage);
hdr.bfReserved1 = 0;
hdr.bfReserved2 = 0;

// Compute the offset to the array of color indices.
hdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER)+pbih->biSize + pbih->biClrUsed * sizeof (RGBQUAD);

// Copy the BITMAPFILEHEADER into the .BMP file.
if (!WriteFile(hf, (LPVOID)&hdr, sizeof(BITMAPFILEHEADER), (LPDWORD)&dwTmp, NULL))
MessageBox(hwnd, TEXT("WriteFileHeader"), TEXT("Error"), MB_OK);

// Copy the BITMAPINFOHEADER and RGBQUAD array into the file.
if (!WriteFile(hf, (LPVOID)pbih, sizeof(BITMAPINFOHEADER)+pbih->biClrUsed * sizeof (RGBQUAD), (LPDWORD)&dwTmp, NULL))
MessageBox(hwnd, TEXT("WriteInfoHeader"), TEXT("Error"), MB_OK);

// Copy the array of color indices into the .BMP file.
dwTotal = cb = pbih->biSizeImage;
hp = lpBits;
if (!WriteFile(hf, (LPSTR)hp, (int)cb, (LPDWORD)&dwTmp, NULL))
MessageBox(hwnd, TEXT("WriteFile"), TEXT("Error"), MB_OK);

// Close the .BMP file.
if (!CloseHandle(hf))
MessageBox(hwnd, TEXT("CloseHandle"), TEXT("Error"), MB_OK);

// Free memory.
GlobalFree((HGLOBAL)lpBits);
}

PBITMAPINFO CreateBitmapInfoStruct(HWND hwnd, HBITMAP hBmp) {
BITMAP bmp;
PBITMAPINFO pbmi;
WORD cClrBits;

// Retrieve the bitmap color format, width, and height.
if (!GetObject(hBmp, sizeof(BITMAP), (LPSTR)&bmp))
MessageBox(hwnd, TEXT("GetObject"), TEXT("Error"), MB_OK);

// Convert the color format to a count of bits.
cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel);
if (cClrBits == 1) cClrBits = 1;
else if (cClrBits <= 4) cClrBits = 4;
else if (cClrBits <= 8) cClrBits = 8;
else if (cClrBits <= 16) cClrBits = 16;
else if (cClrBits <= 24) cClrBits = 24;
else cClrBits = 32;

// Allocate memory for the BITMAPINFO structure. (This structure contains a
// BITMAPINFOHEADER structure and an array of RGBQUAD data structures.)
if (cClrBits != 24)
pbmi = (PBITMAPINFO)LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER)
+sizeof(RGBQUAD)* (1 << cClrBits));
// There is no RGBQUAD array for the 24-bit-per-pixel format.
else
pbmi = (PBITMAPINFO)LocalAlloc(LPTR, sizeof(BITMAPINFOHEADER));

// Initialize the fields in the BITMAPINFO structure.
pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
pbmi->bmiHeader.biWidth = bmp.bmWidth;
pbmi->bmiHeader.biHeight = bmp.bmHeight;
pbmi->bmiHeader.biPlanes = bmp.bmPlanes;
pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel;
if (cClrBits < 24)
pbmi->bmiHeader.biClrUsed = (1 << cClrBits);

// If the bitmap is not compressed, set the BI_RGB flag.
pbmi->bmiHeader.biCompression = BI_RGB;

// Compute the number of bytes in the array of color indices and store the result in biSizeImage.
// For Windows NT, the width must be DWORD aligned unless the bitmap is RLE compressed.
// This example shows this.
// For Windows 95/98/Me, the width must be WORD aligned unless the bitmap is RLE compressed.
pbmi->bmiHeader.biSizeImage = ((pbmi->bmiHeader.biWidth * cClrBits + 31) & ~31)
/ 8 * pbmi->bmiHeader.biHeight;

// Set biClrImportant to 0, indicating that all of the device colors are important.
pbmi->bmiHeader.biClrImportant = 0;

return pbmi; // return BITMAPINFO
}
[/cpp]

Would it simply involve continuously grabbing frames until the function is told to stop? (i.e. grabbing frames and putting to clipboard until stopped)

Thanks in advance!

[Uni Git]

Anyone know how to even start?

[FPSMango]

[QUOTE=Uni Git;45659658]Anyone know how to even start?[/QUOTE]

A quick Google search suggested using built-in AVI functions for windows. What I think you would do is define what frame-rate you're going to use in the AVI header and take that amount of pictures each second and write them to the file via a stream. When you've finished close the stream and you should have a working avi file. (This is just speculation though as I have never looked deep into the windows api)

[url]http://msdn.microsoft.com/en-us/library/windows/desktop/dd756808(v=vs.85).aspx[/url]