直接操作 SDL_Overlay YUV叠加上的像素

根据这篇解码出yuv数据后

海思h264解码库

y,u,v数据全部存进数组内，

IntPtr y = _decodeFrame.pY;

IntPtr v = _decodeFrame.pV;

IntPtr u = _decodeFrame.pU;

byte[] ys = new byte[yLength];

Marshal.Copy(y, ys, 0, yLength);

byte[] vs = new byte[uLength];

Marshal.Copy(v, vs, 0, uLength);

byte[] us = new byte[uLength];

Marshal.Copy(u, us, 0, uLength);

rgb转yuv转换矩阵C++，网上其他的不能用

//转换矩阵
#define MY(a,b,c) (( a*  0.2989  + b*  0.5866  + c*  0.1145))
#define MU(a,b,c) (( a*(-0.1688) + b*(-0.3312) + c*  0.5000 + 128))
#define MV(a,b,c) (( a*  0.5000  + b*(-0.4184) + c*(-0.0816) + 128))

简单写个画线的函数以说明，遍历像素修改效率很低 1920为视频宽 1080p

private void drawLineYUV(Point pnt1, Point pnt2, ref byte[] ys, ref byte[] vs, ref byte[] us, byte R, byte G, byte B)

        {

            //y1 = k x1 + b  b = y1 - k x1

            //    y2 = k x2 + b k = (y2 - b)/ x2      k = (y2 - y1 - k x1)/ x2

            //(x-x1)/(x2-x1)=(y-y1)/(y2-y1)

            int x1 = pnt1.X;

            int x2 = pnt2.X;

            int y1 = pnt1.Y;

            int y2 = pnt2.Y;

            double k = ;

            double b = ;

            if (x1 == x2)

            {

                int ymin = y1, ymax = y2;

                if (y1 > y2)

                {

                    ymin = y2;

                    ymax = y1;

                }

                for (int h = ymin; h <= ymin; h++)

                {

                    int Y = (int)(0.299 * R + 0.587 * G + 0.114 * B);

                    ys[h *  + x1] = (byte)Y;

                    vs[(int)((h *  + x1 * ) / )] = (byte)(int)(R * 0.5000 + G * (-0.4184) + B * (-0.0816) + );

                    us[(int)((h *  + x1 * ) / )] = (byte)(int)(R * (-0.1688) + G * (-0.3312) + B * 0.5000 + );

                }

            }

            else

            {

                int ymin = y1, ymax = y2;

                if (y1 > y2)

                {

                    ymin = y2;

                    ymax = y1;

                }

                int xmin = x1, xmax = x2;

                if (y1 > y2)

                {

                    xmin = x2;

                    xmax = x1;

                }

                k = (double)(ymax - ymin) / (double)(xmax - xmin);

                b = ymin - k * xmin;

                for (int w = xmin; w < xmax; w++)

                {

                    for (int h = ymin; h < ymax; h++)

                    {

                        if (Math.Abs(h - k * w - b) < )

                        {

                            int Y = (int)(0.299 * R + 0.587 * G + 0.114 * B);

                            ys[h *  + w] = (byte)Y;

                            vs[(int)((h *  + w * ) / )] = (byte)(int)(R * 0.5000 + G * (-0.4184) + B * (-0.0816) + );

                            us[(int)((h *  + w * ) / )] = (byte)(int)(R * (-0.1688) + G * (-0.3312) + B * 0.5000 + );

                        }

                    }

                }

            }

        }

巴特西

直接操作 SDL_Overlay YUV叠加上的像素

海思h264解码库

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