Set a bitmap to IMediaSample - c++

Question

As an example, a IMediaSample is filled by random data to test a DirectShow Video Source Filter:
HRESULT CVCamStream::FillBuffer(IMediaSample *pms)
{
REFERENCE_TIME rtNow;
REFERENCE_TIME avgFrameTime = ((VIDEOINFOHEADER*)m_mt.pbFormat)->AvgTimePerFrame;
rtNow = m_rtLastTime;
m_rtLastTime += avgFrameTime;
pms->SetTime(&rtNow, &m_rtLastTime);
pms->SetSyncPoint(TRUE);
BYTE *pData;
long lDataLen;
pms->GetPointer(&pData);
lDataLen = pms->GetSize();
for(int i = 0; i < lDataLen; ++i) pData[i] = rand();
}
Instead, I want to fill the buffer with a bitmap loaded from file-system, and this is what I'm trying to do:
AM_MEDIA_TYPE *mt;
HRESULT hr;
hr = pms->GetMediaType(&mt);
if (FAILED(hr)) return hr;
VIDEOINFOHEADER *pVih;
if ((mt->formattype == FORMAT_VideoInfo) &&
(mt->cbFormat >= sizeof(VIDEOINFOHEADER)) &&
(mt->pbFormat != NULL))
{
pVih = (VIDEOINFOHEADER*)mt->pbFormat;
}
else
{
FreeMediaType(*mt);
return VFW_E_INVALIDMEDIATYPE;
}
DWORD dwBmpSize = ((640 * 3 + 31) / 32) * 4 * 480; // 640x480x24bit
HANDLE hDIB = GlobalAlloc(GHND, dwBmpSize);
char *lpbitmap = (char *)GlobalLock(hDIB);
HBITMAP hBMP = (HBITMAP)LoadImage(NULL, "path/to/my/image.png", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
HDC hdc = GetDC(NULL);
GetDIBits(hdc, hBMP, 0, 480, lpbitmap, (BITMAPINFO*)&pVih->bmiHeader, DIB_RGB_COLORS);
SetDIBitsToDevice(
hdc, 0, 0,
pVih->bmiHeader.biWidth,
pVih->bmiHeader.biHeight,
0, 0,
0,
pVih->bmiHeader.biHeight,
lpbitmap,
(BITMAPINFO*)&pVih->bmiHeader,
DIB_RGB_COLORS
);
But when I try it with Skype is just crashes...
A part any hint about the code above, how I'm supposed to debug such a filter?

Answer 1

Here the working code to fill IMediaSample with a bitmap:
HRESULT CVCamStream::FillBuffer(IMediaSample *pms)
{
REFERENCE_TIME rtNow;
REFERENCE_TIME avgFrameTime = ((VIDEOINFOHEADER*)m_mt.pbFormat)->AvgTimePerFrame;
rtNow = m_rtLastTime;
m_rtLastTime += avgFrameTime;
pms->SetTime(&rtNow, &m_rtLastTime);
pms->SetSyncPoint(TRUE);
BYTE *pData;
long lDataLen;
pms->GetPointer(&pData);
lDataLen = pms->GetSize();
HDC hdc = GetDC(NULL);
HBITMAP hBmp = (HBITMAP)LoadImage(NULL, "path/to/image.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
BITMAP bmp;
GetObject(hBmp, sizeof(BITMAP), &bmp);
BITMAPINFOHEADER bi;
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = bmp.bmWidth;
bi.biHeight = bmp.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = 24;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;
DWORD dwBmpSize = ((bmp.bmWidth * bi.biBitCount + 31) / 32) * 4 * bmp.bmHeight;
HANDLE hDIB = GlobalAlloc(GHND, dwBmpSize);
char *lpbitmap = (char *)GlobalLock(hDIB);
GetDIBits(hdc, hBmp, 0, (UINT)bmp.bmHeight, lpbitmap, (BITMAPINFO *)&bi, DIB_RGB_COLORS);
memcpy(pData, lpbitmap, lDataLen);
return NOERROR;
} // FillBuffer