forked from KolibriOS/kolibrios
291 lines
7.5 KiB
C
291 lines
7.5 KiB
C
#include <math.h>
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static float coef32[31]; /* 32 pt dct coefs */
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void fdct_init() /* gen coef for N=32 (31 coefs) */
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{
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int p, n, i, k;
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double t, pi;
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pi = 4.0 * atan(1.0);
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n = 16;
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k = 0;
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for (i = 0; i < 5; i++, n = n / 2) {
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for (p = 0; p < n; p++, k++) {
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t = (pi / (4 * n)) * (2 * p + 1);
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coef32[k] = (float) (0.50 / cos(t));
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}
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}
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}
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static void forward_bf(int m, int n, float x[], float f[], float coef[])
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{
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int i, j, n2;
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int p, q, p0, k;
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p0 = 0;
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n2 = n >> 1;
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for (i = 0; i < m; i++, p0 += n) {
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k = 0;
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p = p0;
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q = p + n - 1;
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for (j = 0; j < n2; j++, p++, q--, k++) {
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f[p] = x[p] + x[q];
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f[n2 + p] = coef[k] * (x[p] - x[q]);
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}
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}
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}
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/*------------------------------------------------------------*/
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static void back_bf(int m, int n, float x[], float f[])
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{
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int i, j, n2, n21;
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int p, q, p0;
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p0 = 0;
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n2 = n >> 1;
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n21 = n2 - 1;
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for (i = 0; i < m; i++, p0 += n) {
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p = p0;
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q = p0;
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for (j = 0; j < n2; j++, p += 2, q++)
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f[p] = x[q];
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p = p0 + 1;
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for (j = 0; j < n21; j++, p += 2, q++)
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f[p] = x[q] + x[q + 1];
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f[p] = x[q];
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}
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}
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/*------------------------------------------------------------*/
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extern int m_enableEQ;
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extern float m_equalizer[32];
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void fdct32(float x[], float c[])
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{
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float a[32]; /* ping pong buffers */
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float b[32];
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int p, q;
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if (m_enableEQ) {
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for (p = 0; p < 32; p++) x[p] *= m_equalizer[p];
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}
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/* special first stage */
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for (p = 0, q = 31; p < 16; p++, q--) {
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a[p] = x[p] + x[q];
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a[16 + p] = coef32[p] * (x[p] - x[q]);
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}
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forward_bf(2, 16, a, b, coef32 + 16);
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forward_bf(4, 8, b, a, coef32 + 16 + 8);
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forward_bf(8, 4, a, b, coef32 + 16 + 8 + 4);
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forward_bf(16, 2, b, a, coef32 + 16 + 8 + 4 + 2);
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back_bf(8, 4, a, b);
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back_bf(4, 8, b, a);
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back_bf(2, 16, a, b);
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back_bf(1, 32, b, c);
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}
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/*------------------------------------------------------------*/
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void fdct32_dual(float x[], float c[])
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{
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float a[32]; /* ping pong buffers */
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float b[32];
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int p, pp, qq;
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if (m_enableEQ) {
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for (p = 0; p < 32; p++) x[p] *= m_equalizer[p];
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}
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/* special first stage for dual chan (interleaved x) */
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pp = 0;
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qq = 2 * 31;
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for (p = 0; p < 16; p++, pp += 2, qq -= 2)
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{
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a[p] = x[pp] + x[qq];
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a[16 + p] = coef32[p] * (x[pp] - x[qq]);
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}
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forward_bf(2, 16, a, b, coef32 + 16);
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forward_bf(4, 8, b, a, coef32 + 16 + 8);
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forward_bf(8, 4, a, b, coef32 + 16 + 8 + 4);
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forward_bf(16, 2, b, a, coef32 + 16 + 8 + 4 + 2);
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back_bf(8, 4, a, b);
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back_bf(4, 8, b, a);
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back_bf(2, 16, a, b);
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back_bf(1, 32, b, c);
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}
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/*---------------convert dual to mono------------------------------*/
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void fdct32_dual_mono(float x[], float c[])
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{
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float a[32]; /* ping pong buffers */
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float b[32];
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float t1, t2;
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int p, pp, qq;
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/* special first stage */
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pp = 0;
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qq = 2 * 31;
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for (p = 0; p < 16; p++, pp += 2, qq -= 2)
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{
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t1 = 0.5F * (x[pp] + x[pp + 1]);
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t2 = 0.5F * (x[qq] + x[qq + 1]);
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a[p] = t1 + t2;
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a[16 + p] = coef32[p] * (t1 - t2);
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}
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forward_bf(2, 16, a, b, coef32 + 16);
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forward_bf(4, 8, b, a, coef32 + 16 + 8);
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forward_bf(8, 4, a, b, coef32 + 16 + 8 + 4);
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forward_bf(16, 2, b, a, coef32 + 16 + 8 + 4 + 2);
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back_bf(8, 4, a, b);
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back_bf(4, 8, b, a);
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back_bf(2, 16, a, b);
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back_bf(1, 32, b, c);
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}
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/*------------------------------------------------------------*/
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/*---------------- 16 pt fdct -------------------------------*/
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void fdct16(float x[], float c[])
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{
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float a[16]; /* ping pong buffers */
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float b[16];
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int p, q;
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/* special first stage (drop highest sb) */
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a[0] = x[0];
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a[8] = coef32[16] * x[0];
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for (p = 1, q = 14; p < 8; p++, q--)
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{
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a[p] = x[p] + x[q];
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a[8 + p] = coef32[16 + p] * (x[p] - x[q]);
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}
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forward_bf(2, 8, a, b, coef32 + 16 + 8);
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forward_bf(4, 4, b, a, coef32 + 16 + 8 + 4);
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forward_bf(8, 2, a, b, coef32 + 16 + 8 + 4 + 2);
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back_bf(4, 4, b, a);
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back_bf(2, 8, a, b);
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back_bf(1, 16, b, c);
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}
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/*------------------------------------------------------------*/
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/*---------------- 16 pt fdct dual chan---------------------*/
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void fdct16_dual(float x[], float c[])
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{
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float a[16]; /* ping pong buffers */
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float b[16];
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int p, pp, qq;
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/* special first stage for interleaved input */
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a[0] = x[0];
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a[8] = coef32[16] * x[0];
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pp = 2;
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qq = 2 * 14;
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for (p = 1; p < 8; p++, pp += 2, qq -= 2)
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{
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a[p] = x[pp] + x[qq];
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a[8 + p] = coef32[16 + p] * (x[pp] - x[qq]);
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}
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forward_bf(2, 8, a, b, coef32 + 16 + 8);
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forward_bf(4, 4, b, a, coef32 + 16 + 8 + 4);
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forward_bf(8, 2, a, b, coef32 + 16 + 8 + 4 + 2);
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back_bf(4, 4, b, a);
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back_bf(2, 8, a, b);
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back_bf(1, 16, b, c);
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}
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/*------------------------------------------------------------*/
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/*---------------- 16 pt fdct dual to mono-------------------*/
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void fdct16_dual_mono(float x[], float c[])
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{
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float a[16]; /* ping pong buffers */
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float b[16];
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float t1, t2;
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int p, pp, qq;
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/* special first stage */
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a[0] = 0.5F * (x[0] + x[1]);
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a[8] = coef32[16] * a[0];
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pp = 2;
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qq = 2 * 14;
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for (p = 1; p < 8; p++, pp += 2, qq -= 2)
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{
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t1 = 0.5F * (x[pp] + x[pp + 1]);
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t2 = 0.5F * (x[qq] + x[qq + 1]);
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a[p] = t1 + t2;
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a[8 + p] = coef32[16 + p] * (t1 - t2);
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}
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forward_bf(2, 8, a, b, coef32 + 16 + 8);
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forward_bf(4, 4, b, a, coef32 + 16 + 8 + 4);
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forward_bf(8, 2, a, b, coef32 + 16 + 8 + 4 + 2);
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back_bf(4, 4, b, a);
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back_bf(2, 8, a, b);
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back_bf(1, 16, b, c);
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}
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/*------------------------------------------------------------*/
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/*---------------- 8 pt fdct -------------------------------*/
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void fdct8(float x[], float c[])
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{
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float a[8]; /* ping pong buffers */
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float b[8];
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int p, q;
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/* special first stage */
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b[0] = x[0] + x[7];
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b[4] = coef32[16 + 8] * (x[0] - x[7]);
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for (p = 1, q = 6; p < 4; p++, q--)
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{
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b[p] = x[p] + x[q];
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b[4 + p] = coef32[16 + 8 + p] * (x[p] - x[q]);
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}
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forward_bf(2, 4, b, a, coef32 + 16 + 8 + 4);
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forward_bf(4, 2, a, b, coef32 + 16 + 8 + 4 + 2);
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back_bf(2, 4, b, a);
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back_bf(1, 8, a, c);
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}
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/*---------------- 8 pt fdct dual chan---------------------*/
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void fdct8_dual(float x[], float c[])
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{
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float a[8]; /* ping pong buffers */
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float b[8];
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int p, pp, qq;
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/* special first stage for interleaved input */
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b[0] = x[0] + x[14];
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b[4] = coef32[16 + 8] * (x[0] - x[14]);
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pp = 2;
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qq = 2 * 6;
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for (p = 1; p < 4; p++, pp += 2, qq -= 2)
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{
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b[p] = x[pp] + x[qq];
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b[4 + p] = coef32[16 + 8 + p] * (x[pp] - x[qq]);
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}
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forward_bf(2, 4, b, a, coef32 + 16 + 8 + 4);
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forward_bf(4, 2, a, b, coef32 + 16 + 8 + 4 + 2);
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back_bf(2, 4, b, a);
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back_bf(1, 8, a, c);
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}
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/*---------------- 8 pt fdct dual to mono---------------------*/
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void fdct8_dual_mono(float x[], float c[])
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{
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float a[8]; /* ping pong buffers */
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float b[8];
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float t1, t2;
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int p, pp, qq;
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/* special first stage */
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t1 = 0.5F * (x[0] + x[1]);
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t2 = 0.5F * (x[14] + x[15]);
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b[0] = t1 + t2;
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b[4] = coef32[16 + 8] * (t1 - t2);
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pp = 2;
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qq = 2 * 6;
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for (p = 1; p < 4; p++, pp += 2, qq -= 2)
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{
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t1 = 0.5F * (x[pp] + x[pp + 1]);
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t2 = 0.5F * (x[qq] + x[qq + 1]);
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b[p] = t1 + t2;
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b[4 + p] = coef32[16 + 8 + p] * (t1 - t2);
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}
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forward_bf(2, 4, b, a, coef32 + 16 + 8 + 4);
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forward_bf(4, 2, a, b, coef32 + 16 + 8 + 4 + 2);
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back_bf(2, 4, b, a);
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back_bf(1, 8, a, c);
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}
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