1 int zigzagtable[64] = {
2 0, 1, 5, 6, 14, 15, 27, 28,
3 2, 4, 7, 13, 16, 26, 29, 42,
4 3, 8, 12, 17, 25, 30, 41, 43,
5 9, 11, 18, 24, 31, 40, 44, 53,
6 10, 19, 23, 32, 39, 45, 52, 54,
7 20, 22, 33, 38, 46, 51, 55, 60,
8 21, 34, 37, 47, 50, 56, 59, 61,
9 35, 36, 48, 49, 57, 58, 62, 63};
11 static double table[8][8] =
13 {0.707106781186548,0.707106781186548,0.707106781186548,0.707106781186548,0.707106781186548,0.707106781186548,0.707106781186548,0.707106781186548},
14 {0.980785280403230,0.831469612302545,0.555570233019602,0.195090322016128,-0.195090322016128,-0.555570233019602,-0.831469612302545,-0.980785280403230},
15 {0.923879532511287,0.382683432365090,-0.382683432365090,-0.923879532511287,-0.923879532511287,-0.382683432365090,0.382683432365090,0.923879532511287},
16 {0.831469612302545,-0.195090322016128,-0.980785280403230,-0.555570233019602,0.555570233019602,0.980785280403230,0.195090322016129,-0.831469612302545},
17 {0.707106781186548,-0.707106781186547,-0.707106781186548,0.707106781186547,0.707106781186548,-0.707106781186547,-0.707106781186547,0.707106781186547},
18 {0.555570233019602,-0.980785280403230,0.195090322016128,0.831469612302545,-0.831469612302545,-0.195090322016128,0.980785280403231,-0.555570233019602},
19 {0.382683432365090,-0.923879532511287,0.923879532511287,-0.382683432365090,-0.382683432365091,0.923879532511287,-0.923879532511286,0.382683432365090},
20 {0.195090322016128,-0.555570233019602,0.831469612302545,-0.980785280403231,0.980785280403230,-0.831469612302545,0.555570233019602,-0.195090322016129}
34 c+=table[u][x]*src[v*8+x];
44 c+=table[v][y]*tmp[y*8+u];
46 src[v*8+u] = (int)(c*0.25+0.5);
60 c+=table[u][x]*src[y*8+u];
70 c+=table[v][y]*tmp[v*8+x];
72 src[y*8+x] = (int)(c*0.25+0.5);
76 static double c[8] = {1.0,
77 0.980785280403230, // cos(Pi*1/16), sin(Pi*7/16)
78 0.923879532511287, // cos(Pi*2/16), sin(Pi*6/16)
79 0.831469612302545, // cos(Pi*3/16), sin(Pi*5/16)
80 0.707106781186548, // cos(Pi*4/16), sin(Pi*4/16), 1/sqrt(2)
81 0.555570233019602, // cos(Pi*5/16), sin(Pi*3/16)
82 0.382683432365090, // cos(Pi*6/16), sin(Pi*2/16)
83 0.195090322016128 // cos(Pi*7/16), sin(Pi*1/16)
87 static int ccquant = -1;
89 void preparequant(int quant)
93 cc[0] = c[0]/(quant*2*4);
94 cc[1] = c[1]/(quant*2*4);
95 cc[2] = c[2]/(quant*2*4);
96 cc[3] = c[3]/(quant*2*4);
97 cc[4] = c[4]/(quant*2*4);
98 cc[5] = c[5]/(quant*2*4);
99 cc[6] = c[6]/(quant*2*4);
100 cc[7] = c[7]/(quant*2*4);
104 inline static void innerdct(const double*a,double*b, const double*c)
111 //{ 1, 3, 5, 7, -7, -5, -3, -1},
112 //{ 3, -7, -1, -5, 5, 1, 7, -3},
113 //{ 5, -1, 7, 3, -3, -7, 1, -5},
114 //{ 7, -5, 3, -1, 1, -3, 5, -7}
115 double b0,b1,b2,b3,b4,b5;
125 b[2*8] = (b2-b5)*c[2] + (b3-b4)*c[6];
126 b[6*8] = (b2-b5)*c[6] + (b4-b3)*c[2];
133 b[1*8] = b0*c[1] + b1*c[3] + b2*c[5] + b3*c[7];
134 b[3*8] = b0*c[3] - b1*c[7] - b2*c[1] - b3*c[5];
135 b[5*8] = b0*c[5] - b1*c[1] + b2*c[7] + b3*c[3];
136 b[7*8] = b0*c[7] - b1*c[5] + b2*c[3] - b3*c[1];
139 void dct2(int*src, int*dest)
141 double tmp[64], tmp2[64];
150 double* a=&tmp2[v*8];
161 int v = (int)(tmp2[t]);
162 dest[zigzagtable[t]] = v;
172 tmp[zigzagtable[t]] = src[t];
174 memcpy(src, tmp, sizeof(int)*64);