/*
This file is part of jpcsp.
Jpcsp is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Jpcsp is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Jpcsp. If not, see <http://www.gnu.org/licenses/>.
*/
package jpcsp.media.codec.util;
// Template for the Discrete Cosine Transform for 32 samples
public class Dct32 {
/* tab[i][j] = 1.0 / (2.0 * cos(pi*(2*k+1) / 2^(6 - j))) */
/* cos(i*pi/64) */
public static final float COS0_0 = (float) (0.50060299823519630134/2);
public static final float COS0_1 = (float) (0.50547095989754365998/2);
public static final float COS0_2 = (float) (0.51544730992262454697/2);
public static final float COS0_3 = (float) (0.53104259108978417447/2);
public static final float COS0_4 = (float) (0.55310389603444452782/2);
public static final float COS0_5 = (float) (0.58293496820613387367/2);
public static final float COS0_6 = (float) (0.62250412303566481615/2);
public static final float COS0_7 = (float) (0.67480834145500574602/2);
public static final float COS0_8 = (float) (0.74453627100229844977/2);
public static final float COS0_9 = (float) (0.83934964541552703873/2);
public static final float COS0_10 = (float) (0.97256823786196069369/2);
public static final float COS0_11 = (float) (1.16943993343288495515/4);
public static final float COS0_12 = (float) (1.48416461631416627724/4);
public static final float COS0_13 = (float) (2.05778100995341155085/8);
public static final float COS0_14 = (float) (3.40760841846871878570/8);
public static final float COS0_15 = (float) (10.19000812354805681150/32);
public static final float COS1_0 = (float) (0.50241928618815570551/2);
public static final float COS1_1 = (float) (0.52249861493968888062/2);
public static final float COS1_2 = (float) (0.56694403481635770368/2);
public static final float COS1_3 = (float) (0.64682178335999012954/2);
public static final float COS1_4 = (float) (0.78815462345125022473/2);
public static final float COS1_5 = (float) (1.06067768599034747134/4);
public static final float COS1_6 = (float) (1.72244709823833392782/4);
public static final float COS1_7 = (float) (5.10114861868916385802/16);
public static final float COS2_0 = (float) (0.50979557910415916894/2);
public static final float COS2_1 = (float) (0.60134488693504528054/2);
public static final float COS2_2 = (float) (0.89997622313641570463/2);
public static final float COS2_3 = (float) (2.56291544774150617881/8);
public static final float COS3_0 = (float) (0.54119610014619698439/2);
public static final float COS3_1 = (float) (1.30656296487637652785/4);
public static final float COS4_0 = (float) (0.70710678118654752439/2);
// butterfly operator
private static void BF(float[] val, int a, int b, float c, int s) {
float tmp0 = val[a] + val[b];
float tmp1 = val[a] - val[b];
val[a] = tmp0;
val[b] = tmp1 * c * (1 << s);
}
private static void BF0(float[] tab, int tabOffset, float[] val, int a, int b, float c, int s) {
float tmp0 = tab[tabOffset + a] + tab[tabOffset + b];
float tmp1 = tab[tabOffset + a] - tab[tabOffset + b];
val[a] = tmp0;
val[b] = tmp1 * c * (1 << s);
}
private static void BF1(float[] val, int a, int b, int c, int d) {
BF(val, a, b, COS4_0, 1);
BF(val, c, d, -COS4_0, 1);
val[c] += val[d];
}
private static void BF2(float[] val, int a, int b, int c, int d) {
BF(val, a, b, COS4_0, 1);
BF(val, c, d, -COS4_0, 1);
val[c] += val[d];
val[a] += val[c];
val[c] += val[b];
val[b] += val[d];
}
private static void ADD(float[] val, int a, int b) {
val[a] += val[b];
}
// DCT32 without 1/sqrt(2) coef zero scaling.
public static void dct32(float[] out, int outOffset, float[] tab, int tabOffset) {
final float val[] = new float[32];
/* pass 1 */
BF0(tab, tabOffset, val, 0, 31, COS0_0 , 1);
BF0(tab, tabOffset, val, 15, 16, COS0_15, 5);
/* pass 2 */
BF(val, 0, 15, COS1_0 , 1);
BF(val, 16, 31,-COS1_0 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 7, 24, COS0_7 , 1);
BF0(tab, tabOffset, val, 8, 23, COS0_8 , 1);
/* pass 2 */
BF(val, 7, 8, COS1_7 , 4);
BF(val, 23, 24,-COS1_7 , 4);
/* pass 3 */
BF(val, 0, 7, COS2_0 , 1);
BF(val, 8, 15,-COS2_0 , 1);
BF(val, 16, 23, COS2_0 , 1);
BF(val, 24, 31,-COS2_0 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 3, 28, COS0_3 , 1);
BF0(tab, tabOffset, val, 12, 19, COS0_12, 2);
/* pass 2 */
BF(val, 3, 12, COS1_3 , 1);
BF(val, 19, 28,-COS1_3 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 4, 27, COS0_4 , 1);
BF0(tab, tabOffset, val, 11, 20, COS0_11, 2);
/* pass 2 */
BF(val, 4, 11, COS1_4 , 1);
BF(val, 20, 27,-COS1_4 , 1);
/* pass 3 */
BF(val, 3, 4, COS2_3 , 3);
BF(val, 11, 12,-COS2_3 , 3);
BF(val, 19, 20, COS2_3 , 3);
BF(val, 27, 28,-COS2_3 , 3);
/* pass 4 */
BF(val, 0, 3, COS3_0 , 1);
BF(val, 4, 7,-COS3_0 , 1);
BF(val, 8, 11, COS3_0 , 1);
BF(val, 12, 15,-COS3_0 , 1);
BF(val, 16, 19, COS3_0 , 1);
BF(val, 20, 23,-COS3_0 , 1);
BF(val, 24, 27, COS3_0 , 1);
BF(val, 28, 31,-COS3_0 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 1, 30, COS0_1 , 1);
BF0(tab, tabOffset, val, 14, 17, COS0_14, 3);
/* pass 2 */
BF(val, 1, 14, COS1_1 , 1);
BF(val, 17, 30,-COS1_1 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 6, 25, COS0_6 , 1);
BF0(tab, tabOffset, val, 9, 22, COS0_9 , 1);
/* pass 2 */
BF(val, 6, 9, COS1_6 , 2);
BF(val, 22, 25,-COS1_6 , 2);
/* pass 3 */
BF(val, 1, 6, COS2_1 , 1);
BF(val, 9, 14,-COS2_1 , 1);
BF(val, 17, 22, COS2_1 , 1);
BF(val, 25, 30,-COS2_1 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 2, 29, COS0_2 , 1);
BF0(tab, tabOffset, val, 13, 18, COS0_13, 3);
/* pass 2 */
BF(val, 2, 13, COS1_2 , 1);
BF(val, 18, 29,-COS1_2 , 1);
/* pass 1 */
BF0(tab, tabOffset, val, 5, 26, COS0_5 , 1);
BF0(tab, tabOffset, val, 10, 21, COS0_10, 1);
/* pass 2 */
BF(val, 5, 10, COS1_5 , 2);
BF(val, 21, 26,-COS1_5 , 2);
/* pass 3 */
BF(val, 2, 5, COS2_2 , 1);
BF(val, 10, 13,-COS2_2 , 1);
BF(val, 18, 21, COS2_2 , 1);
BF(val, 26, 29,-COS2_2 , 1);
/* pass 4 */
BF(val, 1, 2, COS3_1 , 2);
BF(val, 5, 6,-COS3_1 , 2);
BF(val, 9, 10, COS3_1 , 2);
BF(val, 13, 14,-COS3_1 , 2);
BF(val, 17, 18, COS3_1 , 2);
BF(val, 21, 22,-COS3_1 , 2);
BF(val, 25, 26, COS3_1 , 2);
BF(val, 29, 30,-COS3_1 , 2);
/* pass 5 */
BF1(val, 0, 1, 2, 3);
BF2(val, 4, 5, 6, 7);
BF1(val, 8, 9, 10, 11);
BF2(val, 12, 13, 14, 15);
BF1(val, 16, 17, 18, 19);
BF2(val, 20, 21, 22, 23);
BF1(val, 24, 25, 26, 27);
BF2(val, 28, 29, 30, 31);
/* pass 6 */
ADD(val, 8, 12);
ADD(val, 12, 10);
ADD(val, 10, 14);
ADD(val, 14, 9);
ADD(val, 9, 13);
ADD(val, 13, 11);
ADD(val, 11, 15);
out[outOffset + 0] = val[0];
out[outOffset + 16] = val[1];
out[outOffset + 8] = val[2];
out[outOffset + 24] = val[3];
out[outOffset + 4] = val[4];
out[outOffset + 20] = val[5];
out[outOffset + 12] = val[6];
out[outOffset + 28] = val[7];
out[outOffset + 2] = val[8];
out[outOffset + 18] = val[9];
out[outOffset + 10] = val[10];
out[outOffset + 26] = val[11];
out[outOffset + 6] = val[12];
out[outOffset + 22] = val[13];
out[outOffset + 14] = val[14];
out[outOffset + 30] = val[15];
ADD(val, 24, 28);
ADD(val, 28, 26);
ADD(val, 26, 30);
ADD(val, 30, 25);
ADD(val, 25, 29);
ADD(val, 29, 27);
ADD(val, 27, 31);
out[outOffset + 1] = val[16] + val[24];
out[outOffset + 17] = val[17] + val[25];
out[outOffset + 9] = val[18] + val[26];
out[outOffset + 25] = val[19] + val[27];
out[outOffset + 5] = val[20] + val[28];
out[outOffset + 21] = val[21] + val[29];
out[outOffset + 13] = val[22] + val[30];
out[outOffset + 29] = val[23] + val[31];
out[outOffset + 3] = val[24] + val[20];
out[outOffset + 19] = val[25] + val[21];
out[outOffset + 11] = val[26] + val[22];
out[outOffset + 27] = val[27] + val[23];
out[outOffset + 7] = val[28] + val[18];
out[outOffset + 23] = val[29] + val[19];
out[outOffset + 15] = val[30] + val[17];
out[outOffset + 31] = val[31];
}
}