我有yuv420数据的字节数组.
byte[] yuv420;//yuv data
我该如何将其转换为Image<Bgr, byte>？
我发现一个数学公式转换为RGB然后到,Image<Bgr, byte>但它很慢.有没有办法更快地转换它？
在Emgu有一个类用于转换
COLOR_CONVERSION(enum CV_YUV2RGB Convert YUV color to RGB)
但我无法理解如何使用这个类.有人可以帮忙吗？
static Bitmap ConvertYUV2RGB(byte[] yuvFrame, byte[] rgbFrame, int width, int height)
{
int uIndex = width * height;
int vIndex = uIndex + ((width * height) >> 2);
int gIndex = width * height;
int bIndex = gIndex * 2;
int temp = 0;
//???pic1,RGB????????????int r,g,b;
Bitmap bm = new Bitmap(width, height);
int r = 0;
int g = 0;
int b = 0;
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
// R??
temp = (int)(yuvFrame[y * width + x] + (yuvFrame[vIndex + (y / 2) * (width / 2) + x / 2] - 128) * YUV2RGB_CONVERT_MATRIX[0, 2]);
rgbFrame[y * width + x] = (byte)(temp < 0 ? 0 : (temp > 255 ? 255 : temp));
// G??
temp = (int)(yuvFrame[y * width + x] + (yuvFrame[uIndex + (y / 2) * (width / 2) + x / 2] - 128) * YUV2RGB_CONVERT_MATRIX[1, 1] + (yuvFrame[vIndex + (y / 2) * (width / 2) + x / 2] - 128) * YUV2RGB_CONVERT_MATRIX[1, 2]);
rgbFrame[gIndex + y * width + x] = (byte)(temp < 0 ? 0 : (temp > 255 ? 255 : temp));
// B??
temp = (int)(yuvFrame[y * width + x] + (yuvFrame[uIndex + (y / 2) * (width / 2) + x / 2] - 128) * YUV2RGB_CONVERT_MATRIX[2, 1]);
rgbFrame[bIndex + y * width + x] = (byte)(temp < 0 ? 0 : (temp > 255 ? 255 : temp));
Color c = Color.FromArgb(rgbFrame[y * width + x], rgbFrame[gIndex + y * width + x], rgbFrame[bIndex + y * width + x]);
bm.SetPixel(x, y, c);
}
}
return bm;
}
static double[,] YUV2RGB_CONVERT_MATRIX = new double[3, 3] { { 1, 0, 1.4022 }, { 1, -0.3456, -0.7145 }, { 1, 1.771, 0 } };
static byte clamp(float input)
{
if (input < 0) input = 0;
if (input > 255) input = 255;
return (byte)Math.Abs(input);
}
你很幸运,因为我之前解决了这个问题.代码中有一些链接可以获得更多信息.
通常,在进行图像处理时总是尝试使用指针,并避免在嵌套循环中调用函数.在我的代码中,大小比较是迄今为止最慢的部分,但不幸的是需要它(尝试使用预处理器开关将其关闭).
我不得不说尽管最后我从未使用过这个函数,因为它太慢了,我选择用c ++实现它并使用p调用从c#调用它.
private static unsafe void YUV2RGBManaged(byte[] YUVData, byte[] RGBData, int width, int height)
{
//returned pixel format is 2yuv - i.e. luminance, y, is represented for every pixel and the u and v are alternated
//like this (where Cb = u , Cr = y)
//Y0 Cb Y1 Cr Y2 Cb Y3
/*http://msdn.microsoft.com/en-us/library/ms893078.aspx
*
* C = Y - 16
D = U - 128
E = V - 128
R = clip(( 298 * C + 409 * E + 128) >> 8)
G = clip(( 298 * C - 100 * D - 208 * E + 128) >> 8)
B = clip(( 298 * C + 516 * D + 128) >> 8)
* here are a whole bunch more formats for doing this...
* http://stackoverflow.com/questions/3943779/converting-to-yuv-ycbcr-colour-space-many-versions
*/
fixed(byte* pRGBs = RGBData, pYUVs = YUVData)
{
for (int r = 0; r < height; r++)
{
byte* pRGB = pRGBs + r * width * 3;
byte* pYUV = pYUVs + r * width * 2;
//process two pixels at a time
for (int c = 0; c < width; c += 2)
{
int C1 = pYUV[1] - 16;
int C2 = pYUV[3] - 16;
int D = pYUV[2] - 128;
int E = pYUV[0] - 128;
int R1 = (298 * C1 + 409 * E + 128) >> 8;
int G1 = (298 * C1 - 100 * D - 208 * E + 128) >> 8;
int B1 = (298 * C1 + 516 * D + 128) >> 8;
int R2 = (298 * C2 + 409 * E + 128) >> 8;
int G2 = (298 * C2 - 100 * D - 208 * E + 128) >> 8;
int B2 = (298 * C2 + 516 * D + 128) >> 8;
#if true
//check for overflow
//unsurprisingly this takes the bulk of the time.
pRGB[0] = (byte)(R1 < 0 ? 0 : R1 > 255 ? 255 : R1);
pRGB[1] = (byte)(G1 < 0 ? 0 : G1 > 255 ? 255 : G1);
pRGB[2] = (byte)(B1 < 0 ? 0 : B1 > 255 ? 255 : B1);
pRGB[3] = (byte)(R2 < 0 ? 0 : R2 > 255 ? 255 : R2);
pRGB[4] = (byte)(G2 < 0 ? 0 : G2 > 255 ? 255 : G2);
pRGB[5] = (byte)(B2 < 0 ? 0 : B2 > 255 ? 255 : B2);
#else
pRGB[0] = (byte)(R1);
pRGB[1] = (byte)(G1);
pRGB[2] = (byte)(B1);
pRGB[3] = (byte)(R2);
pRGB[4] = (byte)(G2);
pRGB[5] = (byte)(B2);
#endif
pRGB += 6;
pYUV += 4;
}
}
}
}
并且你决定用c ++实现它
void YUV2RGB(void *yuvDataIn,void *rgbDataOut, int w, int h, int outNCh)
{
const int ch2 = 2 * outNCh;
unsigned char* pRGBs = (unsigned char*)rgbDataOut;
unsigned char* pYUVs = (unsigned char*)yuvDataIn;
for (int r = 0; r < h; r++)
{
unsigned char* pRGB = pRGBs + r * w * outNCh;
unsigned char* pYUV = pYUVs + r * w * 2;
//process two pixels at a time
for (int c = 0; c < w; c += 2)
{
int C1 = pYUV[1] - 16;
int C2 = pYUV[3] - 16;
int D = pYUV[2] - 128;
int E = pYUV[0] - 128;
int R1 = (298 * C1 + 409 * E + 128) >> 8;
int G1 = (298 * C1 - 100 * D - 208 * E + 128) >> 8;
int B1 = (298 * C1 + 516 * D + 128) >> 8;
int R2 = (298 * C2 + 409 * E + 128) >> 8;
int G2 = (298 * C2 - 100 * D - 208 * E + 128) >> 8;
int B2 = (298 * C2 + 516 * D + 128) >> 8;
//unsurprisingly this takes the bulk of the time.
pRGB[0] = (unsigned char)(R1 < 0 ? 0 : R1 > 255 ? 255 : R1);
pRGB[1] = (unsigned char)(G1 < 0 ? 0 : G1 > 255 ? 255 : G1);
pRGB[2] = (unsigned char)(B1 < 0 ? 0 : B1 > 255 ? 255 : B1);
pRGB[3] = (unsigned char)(R2 < 0 ? 0 : R2 > 255 ? 255 : R2);
pRGB[4] = (unsigned char)(G2 < 0 ? 0 : G2 > 255 ? 255 : G2);
pRGB[5] = (unsigned char)(B2 < 0 ? 0 : B2 > 255 ? 255 : B2);
pRGB += ch2;
pYUV += 4;
}
}
}