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1 : /* Copyright (c) 2007-2008 CSIRO
2 : Copyright (c) 2007-2008 Xiph.Org Foundation
3 : Written by Jean-Marc Valin */
4 : /*
5 : Redistribution and use in source and binary forms, with or without
6 : modification, are permitted provided that the following conditions
7 : are met:
8 :
9 : - Redistributions of source code must retain the above copyright
10 : notice, this list of conditions and the following disclaimer.
11 :
12 : - Redistributions in binary form must reproduce the above copyright
13 : notice, this list of conditions and the following disclaimer in the
14 : documentation and/or other materials provided with the distribution.
15 :
16 : THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 : ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 : LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 : A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
20 : OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21 : EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22 : PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
23 : PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
24 : LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
25 : NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
26 : SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 : */
28 :
29 : /* This is a simple MDCT implementation that uses a N/4 complex FFT
30 : to do most of the work. It should be relatively straightforward to
31 : plug in pretty much and FFT here.
32 :
33 : This replaces the Vorbis FFT (and uses the exact same API), which
34 : was a bit too messy and that was ending up duplicating code
35 : (might as well use the same FFT everywhere).
36 :
37 : The algorithm is similar to (and inspired from) Fabrice Bellard's
38 : MDCT implementation in FFMPEG, but has differences in signs, ordering
39 : and scaling in many places.
40 : */
41 :
42 : #ifndef SKIP_CONFIG_H
43 : #ifdef HAVE_CONFIG_H
44 : #include "config.h"
45 : #endif
46 : #endif
47 :
48 : #include "mdct.h"
49 : #include "kiss_fft.h"
50 : #include "_kiss_fft_guts.h"
51 : #include <math.h>
52 : #include "os_support.h"
53 : #include "mathops.h"
54 : #include "stack_alloc.h"
55 :
56 : #if defined(MIPSr1_ASM)
57 : #include "mips/mdct_mipsr1.h"
58 : #endif
59 :
60 :
61 : #ifdef CUSTOM_MODES
62 :
63 : int clt_mdct_init(mdct_lookup *l,int N, int maxshift, int arch)
64 : {
65 : int i;
66 : kiss_twiddle_scalar *trig;
67 : int shift;
68 : int N2=N>>1;
69 : l->n = N;
70 : l->maxshift = maxshift;
71 : for (i=0;i<=maxshift;i++)
72 : {
73 : if (i==0)
74 : l->kfft[i] = opus_fft_alloc(N>>2>>i, 0, 0, arch);
75 : else
76 : l->kfft[i] = opus_fft_alloc_twiddles(N>>2>>i, 0, 0, l->kfft[0], arch);
77 : #ifndef ENABLE_TI_DSPLIB55
78 : if (l->kfft[i]==NULL)
79 : return 0;
80 : #endif
81 : }
82 : l->trig = trig = (kiss_twiddle_scalar*)opus_alloc((N-(N2>>maxshift))*sizeof(kiss_twiddle_scalar));
83 : if (l->trig==NULL)
84 : return 0;
85 : for (shift=0;shift<=maxshift;shift++)
86 : {
87 : /* We have enough points that sine isn't necessary */
88 : #if defined(FIXED_POINT)
89 : #if 1
90 : for (i=0;i<N2;i++)
91 : trig[i] = TRIG_UPSCALE*celt_cos_norm(DIV32(ADD32(SHL32(EXTEND32(i),17),N2+16384),N));
92 : #else
93 : for (i=0;i<N2;i++)
94 : trig[i] = (kiss_twiddle_scalar)MAX32(-32767,MIN32(32767,floor(.5+32768*cos(2*M_PI*(i+.125)/N))));
95 : #endif
96 : #else
97 : for (i=0;i<N2;i++)
98 : trig[i] = (kiss_twiddle_scalar)cos(2*PI*(i+.125)/N);
99 : #endif
100 : trig += N2;
101 : N2 >>= 1;
102 : N >>= 1;
103 : }
104 : return 1;
105 : }
106 :
107 : void clt_mdct_clear(mdct_lookup *l, int arch)
108 : {
109 : int i;
110 : for (i=0;i<=l->maxshift;i++)
111 : opus_fft_free(l->kfft[i], arch);
112 : opus_free((kiss_twiddle_scalar*)l->trig);
113 : }
114 :
115 : #endif /* CUSTOM_MODES */
116 :
117 : /* Forward MDCT trashes the input array */
118 : #ifndef OVERRIDE_clt_mdct_forward
119 0 : void clt_mdct_forward_c(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * OPUS_RESTRICT out,
120 : const opus_val16 *window, int overlap, int shift, int stride, int arch)
121 : {
122 : int i;
123 : int N, N2, N4;
124 : VARDECL(kiss_fft_scalar, f);
125 : VARDECL(kiss_fft_cpx, f2);
126 0 : const kiss_fft_state *st = l->kfft[shift];
127 : const kiss_twiddle_scalar *trig;
128 : opus_val16 scale;
129 : #ifdef FIXED_POINT
130 : /* Allows us to scale with MULT16_32_Q16(), which is faster than
131 : MULT16_32_Q15() on ARM. */
132 : int scale_shift = st->scale_shift-1;
133 : #endif
134 : SAVE_STACK;
135 : (void)arch;
136 0 : scale = st->scale;
137 :
138 0 : N = l->n;
139 0 : trig = l->trig;
140 0 : for (i=0;i<shift;i++)
141 : {
142 0 : N >>= 1;
143 0 : trig += N;
144 : }
145 0 : N2 = N>>1;
146 0 : N4 = N>>2;
147 :
148 0 : ALLOC(f, N2, kiss_fft_scalar);
149 0 : ALLOC(f2, N4, kiss_fft_cpx);
150 :
151 : /* Consider the input to be composed of four blocks: [a, b, c, d] */
152 : /* Window, shuffle, fold */
153 : {
154 : /* Temp pointers to make it really clear to the compiler what we're doing */
155 0 : const kiss_fft_scalar * OPUS_RESTRICT xp1 = in+(overlap>>1);
156 0 : const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+N2-1+(overlap>>1);
157 0 : kiss_fft_scalar * OPUS_RESTRICT yp = f;
158 0 : const opus_val16 * OPUS_RESTRICT wp1 = window+(overlap>>1);
159 0 : const opus_val16 * OPUS_RESTRICT wp2 = window+(overlap>>1)-1;
160 0 : for(i=0;i<((overlap+3)>>2);i++)
161 : {
162 : /* Real part arranged as -d-cR, Imag part arranged as -b+aR*/
163 0 : *yp++ = MULT16_32_Q15(*wp2, xp1[N2]) + MULT16_32_Q15(*wp1,*xp2);
164 0 : *yp++ = MULT16_32_Q15(*wp1, *xp1) - MULT16_32_Q15(*wp2, xp2[-N2]);
165 0 : xp1+=2;
166 0 : xp2-=2;
167 0 : wp1+=2;
168 0 : wp2-=2;
169 : }
170 0 : wp1 = window;
171 0 : wp2 = window+overlap-1;
172 0 : for(;i<N4-((overlap+3)>>2);i++)
173 : {
174 : /* Real part arranged as a-bR, Imag part arranged as -c-dR */
175 0 : *yp++ = *xp2;
176 0 : *yp++ = *xp1;
177 0 : xp1+=2;
178 0 : xp2-=2;
179 : }
180 0 : for(;i<N4;i++)
181 : {
182 : /* Real part arranged as a-bR, Imag part arranged as -c-dR */
183 0 : *yp++ = -MULT16_32_Q15(*wp1, xp1[-N2]) + MULT16_32_Q15(*wp2, *xp2);
184 0 : *yp++ = MULT16_32_Q15(*wp2, *xp1) + MULT16_32_Q15(*wp1, xp2[N2]);
185 0 : xp1+=2;
186 0 : xp2-=2;
187 0 : wp1+=2;
188 0 : wp2-=2;
189 : }
190 : }
191 : /* Pre-rotation */
192 : {
193 0 : kiss_fft_scalar * OPUS_RESTRICT yp = f;
194 0 : const kiss_twiddle_scalar *t = &trig[0];
195 0 : for(i=0;i<N4;i++)
196 : {
197 : kiss_fft_cpx yc;
198 : kiss_twiddle_scalar t0, t1;
199 : kiss_fft_scalar re, im, yr, yi;
200 0 : t0 = t[i];
201 0 : t1 = t[N4+i];
202 0 : re = *yp++;
203 0 : im = *yp++;
204 0 : yr = S_MUL(re,t0) - S_MUL(im,t1);
205 0 : yi = S_MUL(im,t0) + S_MUL(re,t1);
206 0 : yc.r = yr;
207 0 : yc.i = yi;
208 0 : yc.r = PSHR32(MULT16_32_Q16(scale, yc.r), scale_shift);
209 0 : yc.i = PSHR32(MULT16_32_Q16(scale, yc.i), scale_shift);
210 0 : f2[st->bitrev[i]] = yc;
211 : }
212 : }
213 :
214 : /* N/4 complex FFT, does not downscale anymore */
215 0 : opus_fft_impl(st, f2);
216 :
217 : /* Post-rotate */
218 : {
219 : /* Temp pointers to make it really clear to the compiler what we're doing */
220 0 : const kiss_fft_cpx * OPUS_RESTRICT fp = f2;
221 0 : kiss_fft_scalar * OPUS_RESTRICT yp1 = out;
222 0 : kiss_fft_scalar * OPUS_RESTRICT yp2 = out+stride*(N2-1);
223 0 : const kiss_twiddle_scalar *t = &trig[0];
224 : /* Temp pointers to make it really clear to the compiler what we're doing */
225 0 : for(i=0;i<N4;i++)
226 : {
227 : kiss_fft_scalar yr, yi;
228 0 : yr = S_MUL(fp->i,t[N4+i]) - S_MUL(fp->r,t[i]);
229 0 : yi = S_MUL(fp->r,t[N4+i]) + S_MUL(fp->i,t[i]);
230 0 : *yp1 = yr;
231 0 : *yp2 = yi;
232 0 : fp++;
233 0 : yp1 += 2*stride;
234 0 : yp2 -= 2*stride;
235 : }
236 : }
237 : RESTORE_STACK;
238 0 : }
239 : #endif /* OVERRIDE_clt_mdct_forward */
240 :
241 : #ifndef OVERRIDE_clt_mdct_backward
242 0 : void clt_mdct_backward_c(const mdct_lookup *l, kiss_fft_scalar *in, kiss_fft_scalar * OPUS_RESTRICT out,
243 : const opus_val16 * OPUS_RESTRICT window, int overlap, int shift, int stride, int arch)
244 : {
245 : int i;
246 : int N, N2, N4;
247 : const kiss_twiddle_scalar *trig;
248 : (void) arch;
249 :
250 0 : N = l->n;
251 0 : trig = l->trig;
252 0 : for (i=0;i<shift;i++)
253 : {
254 0 : N >>= 1;
255 0 : trig += N;
256 : }
257 0 : N2 = N>>1;
258 0 : N4 = N>>2;
259 :
260 : /* Pre-rotate */
261 : {
262 : /* Temp pointers to make it really clear to the compiler what we're doing */
263 0 : const kiss_fft_scalar * OPUS_RESTRICT xp1 = in;
264 0 : const kiss_fft_scalar * OPUS_RESTRICT xp2 = in+stride*(N2-1);
265 0 : kiss_fft_scalar * OPUS_RESTRICT yp = out+(overlap>>1);
266 0 : const kiss_twiddle_scalar * OPUS_RESTRICT t = &trig[0];
267 0 : const opus_int16 * OPUS_RESTRICT bitrev = l->kfft[shift]->bitrev;
268 0 : for(i=0;i<N4;i++)
269 : {
270 : int rev;
271 : kiss_fft_scalar yr, yi;
272 0 : rev = *bitrev++;
273 0 : yr = ADD32_ovflw(S_MUL(*xp2, t[i]), S_MUL(*xp1, t[N4+i]));
274 0 : yi = SUB32_ovflw(S_MUL(*xp1, t[i]), S_MUL(*xp2, t[N4+i]));
275 : /* We swap real and imag because we use an FFT instead of an IFFT. */
276 0 : yp[2*rev+1] = yr;
277 0 : yp[2*rev] = yi;
278 : /* Storing the pre-rotation directly in the bitrev order. */
279 0 : xp1+=2*stride;
280 0 : xp2-=2*stride;
281 : }
282 : }
283 :
284 0 : opus_fft_impl(l->kfft[shift], (kiss_fft_cpx*)(out+(overlap>>1)));
285 :
286 : /* Post-rotate and de-shuffle from both ends of the buffer at once to make
287 : it in-place. */
288 : {
289 0 : kiss_fft_scalar * yp0 = out+(overlap>>1);
290 0 : kiss_fft_scalar * yp1 = out+(overlap>>1)+N2-2;
291 0 : const kiss_twiddle_scalar *t = &trig[0];
292 : /* Loop to (N4+1)>>1 to handle odd N4. When N4 is odd, the
293 : middle pair will be computed twice. */
294 0 : for(i=0;i<(N4+1)>>1;i++)
295 : {
296 : kiss_fft_scalar re, im, yr, yi;
297 : kiss_twiddle_scalar t0, t1;
298 : /* We swap real and imag because we're using an FFT instead of an IFFT. */
299 0 : re = yp0[1];
300 0 : im = yp0[0];
301 0 : t0 = t[i];
302 0 : t1 = t[N4+i];
303 : /* We'd scale up by 2 here, but instead it's done when mixing the windows */
304 0 : yr = ADD32_ovflw(S_MUL(re,t0), S_MUL(im,t1));
305 0 : yi = SUB32_ovflw(S_MUL(re,t1), S_MUL(im,t0));
306 : /* We swap real and imag because we're using an FFT instead of an IFFT. */
307 0 : re = yp1[1];
308 0 : im = yp1[0];
309 0 : yp0[0] = yr;
310 0 : yp1[1] = yi;
311 :
312 0 : t0 = t[(N4-i-1)];
313 0 : t1 = t[(N2-i-1)];
314 : /* We'd scale up by 2 here, but instead it's done when mixing the windows */
315 0 : yr = ADD32_ovflw(S_MUL(re,t0), S_MUL(im,t1));
316 0 : yi = SUB32_ovflw(S_MUL(re,t1), S_MUL(im,t0));
317 0 : yp1[0] = yr;
318 0 : yp0[1] = yi;
319 0 : yp0 += 2;
320 0 : yp1 -= 2;
321 : }
322 : }
323 :
324 : /* Mirror on both sides for TDAC */
325 : {
326 0 : kiss_fft_scalar * OPUS_RESTRICT xp1 = out+overlap-1;
327 0 : kiss_fft_scalar * OPUS_RESTRICT yp1 = out;
328 0 : const opus_val16 * OPUS_RESTRICT wp1 = window;
329 0 : const opus_val16 * OPUS_RESTRICT wp2 = window+overlap-1;
330 :
331 0 : for(i = 0; i < overlap/2; i++)
332 : {
333 : kiss_fft_scalar x1, x2;
334 0 : x1 = *xp1;
335 0 : x2 = *yp1;
336 0 : *yp1++ = SUB32_ovflw(MULT16_32_Q15(*wp2, x2), MULT16_32_Q15(*wp1, x1));
337 0 : *xp1-- = ADD32_ovflw(MULT16_32_Q15(*wp1, x2), MULT16_32_Q15(*wp2, x1));
338 0 : wp1++;
339 0 : wp2--;
340 : }
341 : }
342 0 : }
343 : #endif /* OVERRIDE_clt_mdct_backward */
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