void ScreenCap(void* buf, int w, int h){     HWND hDesk = GetDesktopWindow();    HDC hScreen = GetDC(hDesk);    int width = w;//GetDeviceCaps(hScreen, HORZRES);    int height = h;//GetDeviceCaps(hScreen, VERTRES);    // if (w != 0)   //     *w = width;   // if (h != 0)    //    *h = height;     HDC hdcMem = CreateCompatibleDC(hScreen);    HBITMAP hBitmap = CreateCompatibleBitmap(hScreen, width, height);     BITMAPINFOHEADER bmi = { 0 };    bmi.biSize = sizeof(BITMAPINFOHEADER);    bmi.biPlanes = 1;    bmi.biBitCount = 24;    bmi.biWidth = width;    bmi.biHeight = height;    bmi.biCompression = BI_RGB;    bmi.biSizeImage = width*height;     SelectObject(hdcMem, hBitmap);    BitBlt(hdcMem, 0, 0, width, height, hScreen, 0, 0, SRCCOPY);     GetDIBits(hdcMem, hBitmap, 0, height, buf, (BITMAPINFO*)&bmi, DIB_RGB_COLORS);     DeleteDC(hdcMem);    ReleaseDC(hDesk, hScreen);    CloseWindow(hDesk);    DeleteObject(hBitmap);}   //// rgb转yuv420//bool  RGB2YUV(unsigned char* RgbBuf,UINT nWidth,UINT nHeight,LPBYTE yuvBuf,unsigned long len){	int i, j;	unsigned char*bufY, *bufU, *bufV, *bufRGB,*bufYuv;	memset(yuvBuf,0,nWidth*nHeight*1.5);	bufY = yuvBuf;	bufV = yuvBuf + nWidth * nHeight;	bufU = bufV + (nWidth * nHeight* 1/4); 	unsigned char y, u, v, r, g, b,testu,testv;	unsigned int ylen = nWidth * nHeight;	unsigned int ulen = (nWidth * nHeight)/4;	unsigned int vlen = (nWidth * nHeight)/4; 	for (j = 0; j
    
     > 8) + 16  ;          			u = (unsigned char)( ( -38 * r -  74 * g + 112 * b + 128) >> 8) + 128 ;          			v = (unsigned char)( ( 112 * r -  94 * g -  18 * b + 128) >> 8) + 128 ;			*(bufY++) = max( 0, min(y, 255 ));			if (j%2==0&&i%2 ==0)			{				if (u>255)				{					u=255;				}				if (u<0)				{					u = 0;				}				*(bufU++) =u;				//存u分量			}			else			{				//存v分量				if (i%2==0)				{					if (v>255)					{						v = 255;					}					if (v<0)					{						v = 0;					}					*(bufV++) =v;				}			}		}	}	//len = nWidth * nHeight+(nWidth * nHeight)/2;	return true;}    char*rgb=new char[width*height*3];ScreenCap(rgb,width,height);RGB2YUV((unsigned char*)rgb,width,height, yuv_buffer,0);
    

这样获得的yuv420 可以直接x264 encode 压缩成视频。即屏幕录像或者屏幕直播