1 files changed, 164 insertions, 0 deletions

diff --git a/apps/codecs/libwma/mdct.c b/apps/codecs/libwma/mdct.c
new file mode 100644
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+++ b/apps/codecs/libwma/mdct.c
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+/*
+ * WMA compatible decoder
+ * Copyright (c) 2002 The FFmpeg Project.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <codecs/lib/codeclib.h>
+#include "wmadec.h"
+#include "wmafixed.h"
+#include "fft.h"
+
+fixed32 *tcosarray[5], *tsinarray[5];
+fixed32 tcos0[1024], tcos1[512], tcos2[256], tcos3[128], tcos4[64];        //these are the sin and cos rotations used by the MDCT
+fixed32 tsin0[1024], tsin1[512], tsin2[256], tsin3[128], tsin4[64];
+
+uint16_t revtab0[1024];
+
+/**
+ * init MDCT or IMDCT computation.
+ */
+int ff_mdct_init(MDCTContext *s, int nbits, int inverse)
+{
+    int n, n4, i;
+   // fixed32 alpha;
+
+
+    memset(s, 0, sizeof(*s));
+    n = 1 << nbits;            //nbits ranges from 12 to 8 inclusive
+    s->nbits = nbits;
+    s->n = n;
+    n4 = n >> 2;
+    s->tcos = tcosarray[12-nbits];
+    s->tsin = tsinarray[12-nbits];
+    for(i=0;i<n4;i++)
+    {
+        //fixed32 pi2 = fixmul32(0x20000, M_PI_F);
+        fixed32 ip = itofix32(i) + 0x2000;
+        ip = ip >> nbits;
+        //ip = fixdiv32(ip,itofix32(n)); // PJJ optimize
+        //alpha = fixmul32(TWO_M_PI_F, ip);
+        //s->tcos[i] = -fixcos32(alpha);        //alpha between 0 and pi/2
+        //s->tsin[i] = -fixsin32(alpha);
+
+    s->tsin[i] = - fsincos(ip<<16, &(s->tcos[i]));            //I can't remember why this works, but it seems to agree for ~24 bits, maybe more!
+    s->tcos[i] *=-1;
+  }
+    (&s->fft)->nbits = nbits-2;
+
+    (&s->fft)->inverse = inverse;
+
+    return 0;
+
+}
+
+/**
+ * Compute inverse MDCT of size N = 2^nbits
+ * @param output N samples
+ * @param input N/2 samples
+ * @param tmp N/2 samples
+ */
+void ff_imdct_calc(MDCTContext *s,
+                   fixed32 *output,
+                   fixed32 *input)
+{
+    int k, n8, n4, n2, n, j,scale;
+    const fixed32 *tcos = s->tcos;
+    const fixed32 *tsin = s->tsin;
+    const fixed32 *in1, *in2;
+    FFTComplex *z1 = (FFTComplex *)output;
+    FFTComplex *z2 = (FFTComplex *)input;
+    int revtabshift = 12 - s->nbits;
+
+    n = 1 << s->nbits;
+
+    n2 = n >> 1;
+    n4 = n >> 2;
+    n8 = n >> 3;
+
+
+    /* pre rotation */
+    in1 = input;
+    in2 = input + n2 - 1;
+
+    for(k = 0; k < n4; k++)
+    {
+        j=revtab0[k<<revtabshift];
+        CMUL(&z1[j].re, &z1[j].im, *in2, *in1, tcos[k], tsin[k]);
+        in1 += 2;
+        in2 -= 2;
+    }
+
+        scale = fft_calc_unscaled(&s->fft, z1);
+
+    /* post rotation + reordering */
+
+    for(k = 0; k < n4; k++)
+    {
+        CMUL(&z2[k].re, &z2[k].im, (z1[k].re), (z1[k].im), tcos[k], tsin[k]);
+    }
+
+    for(k = 0; k < n8; k++)
+    {
+        fixed32 r1,r2,r3,r4,r1n,r2n,r3n;
+
+        r1 = z2[n8 + k].im;
+        r1n = r1 * -1;
+        r2 = z2[n8-1-k].re;
+        r2n = r2 * -1;
+        r3 = z2[k+n8].re;
+        r3n = r3 * -1;
+        r4 = z2[n8-k-1].im;
+
+        output[2*k] = r1n;
+        output[n2-1-2*k] = r1;
+
+        output[2*k+1] = r2;
+        output[n2-1-2*k-1] = r2n;
+
+        output[n2 + 2*k]= r3n;
+        output[n-1- 2*k]= r3n;
+
+        output[n2 + 2*k+1]= r4;
+        output[n-2 - 2 * k] = r4;
+    }
+}
+
+int mdct_init_global()
+{
+    int i,j,m;
+    /* init MDCT */
+    /*TODO:  figure out how to fold this up into one array*/
+    tcosarray[0] = tcos0; tcosarray[1] = tcos1; tcosarray[2] = tcos2; tcosarray[3] = tcos3;tcosarray[4] = tcos4;
+    tsinarray[0] = tsin0; tsinarray[1] = tsin1; tsinarray[2] = tsin2; tsinarray[3] = tsin3;tsinarray[4] = tsin4;
+    /* init the MDCT bit reverse table here rather then in fft_init */
+
+    for(i=0;i<1024;i++)           /*hard coded to a 2048 bit rotation*/
+    {                             /*smaller sizes can reuse the largest*/
+        m=0;
+        for(j=0;j<10;j++)
+        {
+            m |= ((i >> j) & 1) << (10-j-1);
+        }
+
+       revtab0[i]=m;
+    }
+
+    fft_init_global();
+
+    return 0;
+}
+