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-rw-r--r--src/libmad/layer3.c204
1 files changed, 200 insertions, 4 deletions
diff --git a/src/libmad/layer3.c b/src/libmad/layer3.c
index e1b073c71..4e5d3fa02 100644
--- a/src/libmad/layer3.c
+++ b/src/libmad/layer3.c
@@ -1,6 +1,6 @@
/*
* libmad - MPEG audio decoder library
- * Copyright (C) 2000-2003 Underbit Technologies, Inc.
+ * Copyright (C) 2000-2004 Underbit Technologies, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -16,7 +16,7 @@
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
- * $Id: layer3.c,v 1.1 2003/08/14 03:57:13 shank Exp $
+ * $Id: layer3.c,v 1.43 2004/01/23 09:41:32 rob Exp $
*/
# ifdef HAVE_CONFIG_H
@@ -1575,6 +1575,193 @@ void III_aliasreduce(mad_fixed_t xr[576], int lines)
# if defined(ASO_IMDCT)
void III_imdct_l(mad_fixed_t const [18], mad_fixed_t [36], unsigned int);
# else
+# if 1
+static
+void fastsdct(mad_fixed_t const x[9], mad_fixed_t y[18])
+{
+ mad_fixed_t a0, a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11, a12;
+ mad_fixed_t a13, a14, a15, a16, a17, a18, a19, a20, a21, a22, a23, a24, a25;
+ mad_fixed_t m0, m1, m2, m3, m4, m5, m6, m7;
+
+ enum {
+ c0 = MAD_F(0x1f838b8d), /* 2 * cos( 1 * PI / 18) */
+ c1 = MAD_F(0x1bb67ae8), /* 2 * cos( 3 * PI / 18) */
+ c2 = MAD_F(0x18836fa3), /* 2 * cos( 4 * PI / 18) */
+ c3 = MAD_F(0x1491b752), /* 2 * cos( 5 * PI / 18) */
+ c4 = MAD_F(0x0af1d43a), /* 2 * cos( 7 * PI / 18) */
+ c5 = MAD_F(0x058e86a0), /* 2 * cos( 8 * PI / 18) */
+ c6 = -MAD_F(0x1e11f642) /* 2 * cos(16 * PI / 18) */
+ };
+
+ a0 = x[3] + x[5];
+ a1 = x[3] - x[5];
+ a2 = x[6] + x[2];
+ a3 = x[6] - x[2];
+ a4 = x[1] + x[7];
+ a5 = x[1] - x[7];
+ a6 = x[8] + x[0];
+ a7 = x[8] - x[0];
+
+ a8 = a0 + a2;
+ a9 = a0 - a2;
+ a10 = a0 - a6;
+ a11 = a2 - a6;
+ a12 = a8 + a6;
+ a13 = a1 - a3;
+ a14 = a13 + a7;
+ a15 = a3 + a7;
+ a16 = a1 - a7;
+ a17 = a1 + a3;
+
+ m0 = mad_f_mul(a17, -c3);
+ m1 = mad_f_mul(a16, -c0);
+ m2 = mad_f_mul(a15, -c4);
+ m3 = mad_f_mul(a14, -c1);
+ m4 = mad_f_mul(a5, -c1);
+ m5 = mad_f_mul(a11, -c6);
+ m6 = mad_f_mul(a10, -c5);
+ m7 = mad_f_mul(a9, -c2);
+
+ a18 = x[4] + a4;
+ a19 = 2 * x[4] - a4;
+ a20 = a19 + m5;
+ a21 = a19 - m5;
+ a22 = a19 + m6;
+ a23 = m4 + m2;
+ a24 = m4 - m2;
+ a25 = m4 + m1;
+
+ /* output to every other slot for convenience */
+
+ y[ 0] = a18 + a12;
+ y[ 2] = m0 - a25;
+ y[ 4] = m7 - a20;
+ y[ 6] = m3;
+ y[ 8] = a21 - m6;
+ y[10] = a24 - m1;
+ y[12] = a12 - 2 * a18;
+ y[14] = a23 + m0;
+ y[16] = a22 + m7;
+}
+
+static inline
+void sdctII(mad_fixed_t const x[18], mad_fixed_t X[18])
+{
+ mad_fixed_t tmp[9];
+ int i;
+
+ /* scale[i] = 2 * cos(PI * (2 * i + 1) / (2 * 18)) */
+ static mad_fixed_t const scale[9] = {
+ MAD_F(0x1fe0d3b4), MAD_F(0x1ee8dd47), MAD_F(0x1d007930),
+ MAD_F(0x1a367e59), MAD_F(0x16a09e66), MAD_F(0x125abcf8),
+ MAD_F(0x0d8616bc), MAD_F(0x08483ee1), MAD_F(0x02c9fad7)
+ };
+
+ /* divide the 18-point SDCT-II into two 9-point SDCT-IIs */
+
+ /* even input butterfly */
+
+ for (i = 0; i < 9; i += 3) {
+ tmp[i + 0] = x[i + 0] + x[18 - (i + 0) - 1];
+ tmp[i + 1] = x[i + 1] + x[18 - (i + 1) - 1];
+ tmp[i + 2] = x[i + 2] + x[18 - (i + 2) - 1];
+ }
+
+ fastsdct(tmp, &X[0]);
+
+ /* odd input butterfly and scaling */
+
+ for (i = 0; i < 9; i += 3) {
+ tmp[i + 0] = mad_f_mul(x[i + 0] - x[18 - (i + 0) - 1], scale[i + 0]);
+ tmp[i + 1] = mad_f_mul(x[i + 1] - x[18 - (i + 1) - 1], scale[i + 1]);
+ tmp[i + 2] = mad_f_mul(x[i + 2] - x[18 - (i + 2) - 1], scale[i + 2]);
+ }
+
+ fastsdct(tmp, &X[1]);
+
+ /* output accumulation */
+
+ for (i = 3; i < 18; i += 8) {
+ X[i + 0] -= X[(i + 0) - 2];
+ X[i + 2] -= X[(i + 2) - 2];
+ X[i + 4] -= X[(i + 4) - 2];
+ X[i + 6] -= X[(i + 6) - 2];
+ }
+}
+
+static inline
+void dctIV(mad_fixed_t const y[18], mad_fixed_t X[18])
+{
+ mad_fixed_t tmp[18];
+ int i;
+
+ /* scale[i] = 2 * cos(PI * (2 * i + 1) / (4 * 18)) */
+ static mad_fixed_t const scale[18] = {
+ MAD_F(0x1ff833fa), MAD_F(0x1fb9ea93), MAD_F(0x1f3dd120),
+ MAD_F(0x1e84d969), MAD_F(0x1d906bcf), MAD_F(0x1c62648b),
+ MAD_F(0x1afd100f), MAD_F(0x1963268b), MAD_F(0x1797c6a4),
+ MAD_F(0x159e6f5b), MAD_F(0x137af940), MAD_F(0x11318ef3),
+ MAD_F(0x0ec6a507), MAD_F(0x0c3ef153), MAD_F(0x099f61c5),
+ MAD_F(0x06ed12c5), MAD_F(0x042d4544), MAD_F(0x0165547c)
+ };
+
+ /* scaling */
+
+ for (i = 0; i < 18; i += 3) {
+ tmp[i + 0] = mad_f_mul(y[i + 0], scale[i + 0]);
+ tmp[i + 1] = mad_f_mul(y[i + 1], scale[i + 1]);
+ tmp[i + 2] = mad_f_mul(y[i + 2], scale[i + 2]);
+ }
+
+ /* SDCT-II */
+
+ sdctII(tmp, X);
+
+ /* scale reduction and output accumulation */
+
+ X[0] /= 2;
+ for (i = 1; i < 17; i += 4) {
+ X[i + 0] = X[i + 0] / 2 - X[(i + 0) - 1];
+ X[i + 1] = X[i + 1] / 2 - X[(i + 1) - 1];
+ X[i + 2] = X[i + 2] / 2 - X[(i + 2) - 1];
+ X[i + 3] = X[i + 3] / 2 - X[(i + 3) - 1];
+ }
+ X[17] = X[17] / 2 - X[16];
+}
+
+/*
+ * NAME: imdct36
+ * DESCRIPTION: perform X[18]->x[36] IMDCT using Szu-Wei Lee's fast algorithm
+ */
+static inline
+void imdct36(mad_fixed_t const x[18], mad_fixed_t y[36])
+{
+ mad_fixed_t tmp[18];
+ int i;
+
+ /* DCT-IV */
+
+ dctIV(x, tmp);
+
+ /* convert 18-point DCT-IV to 36-point IMDCT */
+
+ for (i = 0; i < 9; i += 3) {
+ y[i + 0] = tmp[9 + (i + 0)];
+ y[i + 1] = tmp[9 + (i + 1)];
+ y[i + 2] = tmp[9 + (i + 2)];
+ }
+ for (i = 9; i < 27; i += 3) {
+ y[i + 0] = -tmp[36 - (9 + (i + 0)) - 1];
+ y[i + 1] = -tmp[36 - (9 + (i + 1)) - 1];
+ y[i + 2] = -tmp[36 - (9 + (i + 2)) - 1];
+ }
+ for (i = 27; i < 36; i += 3) {
+ y[i + 0] = -tmp[(i + 0) - 27];
+ y[i + 1] = -tmp[(i + 1) - 27];
+ y[i + 2] = -tmp[(i + 2) - 27];
+ }
+}
+# else
/*
* NAME: imdct36
* DESCRIPTION: perform X[18]->x[36] IMDCT
@@ -1865,6 +2052,7 @@ void imdct36(mad_fixed_t const X[18], mad_fixed_t x[36])
x[26] = x[27] = MAD_F_MLZ(hi, lo) + t5;
}
+# endif
/*
* NAME: III_imdct_l()
@@ -1929,7 +2117,11 @@ void III_imdct_l(mad_fixed_t const X[18], mad_fixed_t z[36],
break;
case 1: /* start block */
- for (i = 0; i < 18; ++i) z[i] = mad_f_mul(z[i], window_l[i]);
+ for (i = 0; i < 18; i += 3) {
+ z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]);
+ z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]);
+ z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]);
+ }
/* (i = 18; i < 24; ++i) z[i] unchanged */
for (i = 24; i < 30; ++i) z[i] = mad_f_mul(z[i], window_s[i - 18]);
for (i = 30; i < 36; ++i) z[i] = 0;
@@ -1939,7 +2131,11 @@ void III_imdct_l(mad_fixed_t const X[18], mad_fixed_t z[36],
for (i = 0; i < 6; ++i) z[i] = 0;
for (i = 6; i < 12; ++i) z[i] = mad_f_mul(z[i], window_s[i - 6]);
/* (i = 12; i < 18; ++i) z[i] unchanged */
- for (i = 18; i < 36; ++i) z[i] = mad_f_mul(z[i], window_l[i]);
+ for (i = 18; i < 36; i += 3) {
+ z[i + 0] = mad_f_mul(z[i + 0], window_l[i + 0]);
+ z[i + 1] = mad_f_mul(z[i + 1], window_l[i + 1]);
+ z[i + 2] = mad_f_mul(z[i + 2], window_l[i + 2]);
+ }
break;
}
}
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