DCT, IDCT变换--C语言实现

static const double MtxDCT[8][8] =
{
{0.3536,    0.3536,    0.3536,    0.3536,    0.3536,    0.3536,    0.3536,    0.3536},
{0.4904,    0.4157,    0.2778,    0.0975,   -0.0975,   -0.2778,   -0.4157,   -0.4904},
{0.4619,    0.1913,   -0.1913,   -0.4619,   -0.4619,   -0.1913,    0.1913,    0.4619},
{0.4157,   -0.0975,   -0.4904,   -0.2778,    0.2778,    0.4904,    0.0975,   -0.4157},
{0.3536,   -0.3536,   -0.3536,    0.3536,    0.3536,   -0.3536,   -0.3536,    0.3536},
{0.2778,   -0.4904,    0.0975,    0.4157,   -0.4157,   -0.0975,    0.4904,   -0.2778},
{0.1913,   -0.4619,    0.4619,   -0.1913,   -0.1913,    0.4619,   -0.4619,    0.1913},
{0.0975,   -0.2778,    0.4157,   -0.4904,    0.4904,   -0.4157,    0.2778,   -0.0975}
};

static const double MtxIDCT[8][8] =
{
{0.3536,    0.4904,    0.4619,    0.4157,    0.3536,    0.2778,    0.1913,    0.0975},
{0.3536,    0.4157,    0.1913,   -0.0975,   -0.3536,   -0.4904,   -0.4619,   -0.2778},
{0.3536,    0.2778,   -0.1913,   -0.4904,   -0.3536,    0.0975,    0.4619,    0.4157},
{0.3536,    0.0975,   -0.4619,   -0.2778,    0.3536,    0.4157,   -0.1913,   -0.4904},
{0.3536,   -0.0975,   -0.4619,    0.2778,    0.3536,   -0.4157,   -0.1913,    0.4904},
{0.3536,   -0.2778,   -0.1913,    0.4904,   -0.3536,   -0.0975,    0.4619,   -0.4157},
{0.3536,   -0.4157,    0.1913,    0.0975,   -0.3536,    0.4904,   -0.4619,    0.2778},
{0.3536,   -0.4904,    0.4619,   -0.4157,    0.3536,   -0.2778,    0.1913,   -0.0975}
};

class MCU
{
public:
int *operator[] (int row)
{
return data[row];
}

int data[8][8];
};

MCU MtxMulI2D(MCU &left, const double right[8][8])
{
MCU dctBuf;
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
double tempVal = 0.0;
for (int k = 0; k < 8; k++)
{
tempVal += left[i][k] * right[k][j];
}
dctBuf[i][j] = round(tempVal);
}
}
return dctBuf;
}

MCU MtxMulD2I(const double left[8][8], MCU &right)
{
MCU dctBuf;
for (int i = 0; i < 8; i++)
{
for (int j = 0; j < 8; j++)
{
double tempVal = 0.0;
for (int k = 0; k < 8; k++)
{
tempVal += left[i][k] * right[k][j];
}
dctBuf[i][j] = round(tempVal);
}
}
return dctBuf;
}

void DCT(MCU &block)
{
block = MtxMulD2I(MtxDCT, block);
block = MtxMulI2D(block, MtxIDCT);
}

void IDCT(MCU &block)
{
block = MtxMulD2I(MtxIDCT, block);
block = MtxMulI2D(block, MtxDCT);
}

int data2[8][8] =
{
{144,146,149,152,154,156,156,156},
{148,150,152,154,156,156,156,156},
{155,156,157,158,158,157,156,155},
{160,161,161,162,161,159,157,155},
{163,163,164,163,162,160,158,156},
{163,163,164,164,162,160,158,157},
{160,161,162,162,162,161,159,158},
{158,159,161,161,162,161,159,158}
};

int data1[8][8] =
{
{139, 144, 149, 153, 155, 155, 155, 155},
{144, 151, 153, 156, 159, 156, 156, 156},
{150, 155, 160, 163, 158, 156, 156, 156},
{159, 161, 162, 160, 160, 159, 159, 159},
{159, 160, 161, 162, 162, 155, 155, 155},
{161, 161, 161, 161, 160, 157, 157, 157},
{162, 162, 161, 163, 162, 157, 157, 157},
{162, 162, 161, 161, 163, 158, 158, 158}
};

void Show(MCU &block)
{
for (int i=0;i<8;i++)
{
for(int j=0;j<8;j++)
{
printf("%4d ", block[i][j]);
}
printf("\n");
}
}

int main(int argc, char *argv[])
{
MCU block;
for (int i=0;i<8;i++)
{
for(int j=0;j<8;j++)
{
block[i][j] = data1[i][j];
}
}

DCT(block);   // 离散余弦变换
IDCT(block);  // 逆离散余弦变换
Show(block);
return 0;
}