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+/* Copyright (c) 2007-2008 CSIRO
+ Copyright (c) 2007-2008 Xiph.Org Foundation
+ Written by Jean-Marc Valin */
+/*
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ - Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ - Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in the
+ documentation and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+ OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* This is a simple MDCT implementation that uses a N/4 complex FFT
+ to do most of the work. It should be relatively straightforward to
+ plug in pretty much and FFT here.
+
+ This replaces the Vorbis FFT (and uses the exact same API), which
+ was a bit too messy and that was ending up duplicating code
+ (might as well use the same FFT everywhere).
+
+ The algorithm is similar to (and inspired from) Fabrice Bellard's
+ MDCT implementation in FFMPEG, but has differences in signs, ordering
+ and scaling in many places.
+*/
+
+#ifndef SKIP_CONFIG_H
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#endif
+
+#include "mdct.h"
+#include "kiss_fft.h"
+#include "_kiss_fft_guts.h"
+#include <math.h>
+#include "os_support.h"
+#include "mathops.h"
+#include "stack_alloc.h"
+
+#if defined(MIPSr1_ASM)
+#include "mips/mdct_mipsr1.h"
+#endif
+
+
+#ifdef CUSTOM_MODES
+
+int clt_mdct_init(mdct_lookup *l,int N, int maxshift, int arch)
+{
+ int i;
+ kiss_twiddle_scalar *trig;
+ int shift;
+ int N2=N>>1;
+ l->n = N;
+ l->maxshift = maxshift;
+ for (i=0;i<=maxshift;i++)
+ {
+ if (i==0)
+ l->kfft[i] = opus_fft_alloc(N>>2>>i, 0, 0, arch);
+ else
+ l->kfft[i] = opus_fft_alloc_twiddles(N>>2>>i, 0, 0, l->kfft[0], arch);
+#ifndef ENABLE_TI_DSPLIB55
+ if (l->kfft[i]==NULL)
+ return 0;
+#endif
+ }
+ l->trig = trig = (kiss_twiddle_scalar*)opus_alloc((N-(N2>>maxshift))*sizeof(kiss_twiddle_scalar));
+ if (l->trig==NULL)
+ return 0;
+ for (shift=0;shift<=maxshift;shift++)
+ {
+ /* We have enough points that sine isn't necessary */
+#if defined(FIXED_POINT)
+#if 1
+ for (i=0;i<N2;i++)
+ trig[i] = TRIG_UPSCALE*celt_cos_norm(DIV32(ADD32(SHL32(EXTEND32(i),17),N2+16384),N));
+#else
+ for (i=0;i<N2;i++)
+ trig[i] = (kiss_twiddle_scalar)MAX32(-32767,MIN32(32767,floor(.5+32768*cos(2*M_PI*(i+.125)/N))));
+#endif
+#else
+ for (i=0;i<N2;i++)
+ trig[i] = (kiss_twiddle_scalar)cos(2*PI*(i+.125)/N);
+#endif
+ trig += N2;
+ N2 >>= 1;
+ N >>= 1;
+ }
+ return 1;
+}
+
+void clt_mdct_clear(mdct_lookup *l, int arch)
+{
+ int i;
+ for (i=0;i<=l->maxshift;i++)
+ opus_fft_free(l->kfft[i], arch);
+ opus_free((kiss_twiddle_scalar*)l->trig);
+}
+
+#endif /* CUSTOM_MODES */
+
+/* Forward MDCT trashes the input array */
+#ifndef OVERRIDE_clt_mdct_forward
+void clt_mdct_forward_c(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * OPUS_RESTRICT out,
+ const opus_val16 *window, int overlap, int shift, int stride, int arch)
+{
+ int i;
+ int N, N2, N4;
+ VARDECL(kiss_fft_scalar, f);
+ VARDECL(kiss_fft_cpx, f2);
+ const kiss_fft_state *st = l->kfft[shift];
+ const kiss_twiddle_scalar *trig;
+ opus_val16 scale;
+#ifdef FIXED_POINT
+ /* Allows us to scale with MULT16_32_Q16(), which is faster than
+ MULT16_32_Q15() on ARM. */
+ int scale_shift = st->scale_shift-1;
+#endif
+ SAVE_STACK;
+ (void)arch;
+ scale = st->scale;
+
+ N = l->n;
+ trig = l->trig;
+ for (i=0;i<shift;i++)
+ {
+ N >>= 1;
+ trig += N;
+ }
+ N2 = N>>1;
+ N4 = N>>2;
+
+ ALLOC(f, N2, kiss_fft_scalar);
+ ALLOC(f2, N4, kiss_fft_cpx);
+
+ /* Consider the input to be composed of four blocks: [a, b, c, d] */
+ /* Window, shuffle, fold */
+ {
+ /* Temp pointers to make it really clear to the compiler what we're doing */
+ const kiss_fft_scalar * OPUS_RESTRICT xp1 = in+(overlap>>1);
+ const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+N2-1+(overlap>>1);
+ kiss_fft_scalar * OPUS_RESTRICT yp = f;
+ const opus_val16 * OPUS_RESTRICT wp1 = window+(overlap>>1);
+ const opus_val16 * OPUS_RESTRICT wp2 = window+(overlap>>1)-1;
+ for(i=0;i<((overlap+3)>>2);i++)
+ {
+ /* Real part arranged as -d-cR, Imag part arranged as -b+aR*/
+ *yp++ = MULT16_32_Q15(*wp2, xp1[N2]) + MULT16_32_Q15(*wp1,*xp2);
+ *yp++ = MULT16_32_Q15(*wp1, *xp1) - MULT16_32_Q15(*wp2, xp2[-N2]);
+ xp1+=2;
+ xp2-=2;
+ wp1+=2;
+ wp2-=2;
+ }
+ wp1 = window;
+ wp2 = window+overlap-1;
+ for(;i<N4-((overlap+3)>>2);i++)
+ {
+ /* Real part arranged as a-bR, Imag part arranged as -c-dR */
+ *yp++ = *xp2;
+ *yp++ = *xp1;
+ xp1+=2;
+ xp2-=2;
+ }
+ for(;i<N4;i++)
+ {
+ /* Real part arranged as a-bR, Imag part arranged as -c-dR */
+ *yp++ = -MULT16_32_Q15(*wp1, xp1[-N2]) + MULT16_32_Q15(*wp2, *xp2);
+ *yp++ = MULT16_32_Q15(*wp2, *xp1) + MULT16_32_Q15(*wp1, xp2[N2]);
+ xp1+=2;
+ xp2-=2;
+ wp1+=2;
+ wp2-=2;
+ }
+ }
+ /* Pre-rotation */
+ {
+ kiss_fft_scalar * OPUS_RESTRICT yp = f;
+ const kiss_twiddle_scalar *t = &trig[0];
+ for(i=0;i<N4;i++)
+ {
+ kiss_fft_cpx yc;
+ kiss_twiddle_scalar t0, t1;
+ kiss_fft_scalar re, im, yr, yi;
+ t0 = t[i];
+ t1 = t[N4+i];
+ re = *yp++;
+ im = *yp++;
+ yr = S_MUL(re,t0) - S_MUL(im,t1);
+ yi = S_MUL(im,t0) + S_MUL(re,t1);
+ yc.r = yr;
+ yc.i = yi;
+ yc.r = PSHR32(MULT16_32_Q16(scale, yc.r), scale_shift);
+ yc.i = PSHR32(MULT16_32_Q16(scale, yc.i), scale_shift);
+ f2[st->bitrev[i]] = yc;
+ }
+ }
+
+ /* N/4 complex FFT, does not downscale anymore */
+ opus_fft_impl(st, f2);
+
+ /* Post-rotate */
+ {
+ /* Temp pointers to make it really clear to the compiler what we're doing */
+ const kiss_fft_cpx * OPUS_RESTRICT fp = f2;
+ kiss_fft_scalar * OPUS_RESTRICT yp1 = out;
+ kiss_fft_scalar * OPUS_RESTRICT yp2 = out+stride*(N2-1);
+ const kiss_twiddle_scalar *t = &trig[0];
+ /* Temp pointers to make it really clear to the compiler what we're doing */
+ for(i=0;i<N4;i++)
+ {
+ kiss_fft_scalar yr, yi;
+ yr = S_MUL(fp->i,t[N4+i]) - S_MUL(fp->r,t[i]);
+ yi = S_MUL(fp->r,t[N4+i]) + S_MUL(fp->i,t[i]);
+ *yp1 = yr;
+ *yp2 = yi;
+ fp++;
+ yp1 += 2*stride;
+ yp2 -= 2*stride;
+ }
+ }
+ RESTORE_STACK;
+}
+#endif /* OVERRIDE_clt_mdct_forward */
+
+#ifndef OVERRIDE_clt_mdct_backward
+void clt_mdct_backward_c(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * OPUS_RESTRICT out,
+ const opus_val16 * OPUS_RESTRICT window, int overlap, int shift, int stride, int arch)
+{
+ int i;
+ int N, N2, N4;
+ const kiss_twiddle_scalar *trig;
+ (void) arch;
+
+ N = l->n;
+ trig = l->trig;
+ for (i=0;i<shift;i++)
+ {
+ N >>= 1;
+ trig += N;
+ }
+ N2 = N>>1;
+ N4 = N>>2;
+
+ /* Pre-rotate */
+ {
+ /* Temp pointers to make it really clear to the compiler what we're doing */
+ const kiss_fft_scalar * OPUS_RESTRICT xp1 = in;
+ const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+stride*(N2-1);
+ kiss_fft_scalar * OPUS_RESTRICT yp = out+(overlap>>1);
+ const kiss_twiddle_scalar * OPUS_RESTRICT t = &trig[0];
+ const opus_int16 * OPUS_RESTRICT bitrev = l->kfft[shift]->bitrev;
+ for(i=0;i<N4;i++)
+ {
+ int rev;
+ kiss_fft_scalar yr, yi;
+ rev = *bitrev++;
+ yr = ADD32_ovflw(S_MUL(*xp2, t[i]), S_MUL(*xp1, t[N4+i]));
+ yi = SUB32_ovflw(S_MUL(*xp1, t[i]), S_MUL(*xp2, t[N4+i]));
+ /* We swap real and imag because we use an FFT instead of an IFFT. */
+ yp[2*rev+1] = yr;
+ yp[2*rev] = yi;
+ /* Storing the pre-rotation directly in the bitrev order. */
+ xp1+=2*stride;
+ xp2-=2*stride;
+ }
+ }
+
+ opus_fft_impl(l->kfft[shift], (kiss_fft_cpx*)(out+(overlap>>1)));
+
+ /* Post-rotate and de-shuffle from both ends of the buffer at once to make
+ it in-place. */
+ {
+ kiss_fft_scalar * yp0 = out+(overlap>>1);
+ kiss_fft_scalar * yp1 = out+(overlap>>1)+N2-2;
+ const kiss_twiddle_scalar *t = &trig[0];
+ /* Loop to (N4+1)>>1 to handle odd N4. When N4 is odd, the
+ middle pair will be computed twice. */
+ for(i=0;i<(N4+1)>>1;i++)
+ {
+ kiss_fft_scalar re, im, yr, yi;
+ kiss_twiddle_scalar t0, t1;
+ /* We swap real and imag because we're using an FFT instead of an IFFT. */
+ re = yp0[1];
+ im = yp0[0];
+ t0 = t[i];
+ t1 = t[N4+i];
+ /* We'd scale up by 2 here, but instead it's done when mixing the windows */
+ yr = ADD32_ovflw(S_MUL(re,t0), S_MUL(im,t1));
+ yi = SUB32_ovflw(S_MUL(re,t1), S_MUL(im,t0));
+ /* We swap real and imag because we're using an FFT instead of an IFFT. */
+ re = yp1[1];
+ im = yp1[0];
+ yp0[0] = yr;
+ yp1[1] = yi;
+
+ t0 = t[(N4-i-1)];
+ t1 = t[(N2-i-1)];
+ /* We'd scale up by 2 here, but instead it's done when mixing the windows */
+ yr = ADD32_ovflw(S_MUL(re,t0), S_MUL(im,t1));
+ yi = SUB32_ovflw(S_MUL(re,t1), S_MUL(im,t0));
+ yp1[0] = yr;
+ yp0[1] = yi;
+ yp0 += 2;
+ yp1 -= 2;
+ }
+ }
+
+ /* Mirror on both sides for TDAC */
+ {
+ kiss_fft_scalar * OPUS_RESTRICT xp1 = out+overlap-1;
+ kiss_fft_scalar * OPUS_RESTRICT yp1 = out;
+ const opus_val16 * OPUS_RESTRICT wp1 = window;
+ const opus_val16 * OPUS_RESTRICT wp2 = window+overlap-1;
+
+ for(i = 0; i < overlap/2; i++)
+ {
+ kiss_fft_scalar x1, x2;
+ x1 = *xp1;
+ x2 = *yp1;
+ *yp1++ = SUB32_ovflw(MULT16_32_Q15(*wp2, x2), MULT16_32_Q15(*wp1, x1));
+ *xp1-- = ADD32_ovflw(MULT16_32_Q15(*wp1, x2), MULT16_32_Q15(*wp2, x1));
+ wp1++;
+ wp2--;
+ }
+ }
+}
+#endif /* OVERRIDE_clt_mdct_backward */
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