1 /******************************************************************************
2 *
3 * Copyright (C) 2014 The Android Open Source Project
4 * Copyright 2003 - 2004 Open Interface North America, Inc. All rights reserved.
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at:
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 *
18 ******************************************************************************/
19
20 /**********************************************************************************
21 $Revision: #1 $
22 ***********************************************************************************/
23
24 /** @file
25 @ingroup codec_internal
26 */
27
28 /**@addgroup codec_internal*/
29 /**@{*/
30
31 /*
32 * Performs an 8-point Type-II scaled DCT using the Arai-Agui-Nakajima
33 * factorization. The scaling factors are folded into the windowing
34 * constants. 29 adds and 5 16x32 multiplies per 8 samples.
35 */
36
37 #include "oi_codec_sbc_private.h"
38
39 #define AAN_C4_FIX (759250125)/* S1.30 759250125 0.707107*/
40
41 #define AAN_C6_FIX (410903207)/* S1.30 410903207 0.382683*/
42
43 #define AAN_Q0_FIX (581104888)/* S1.30 581104888 0.541196*/
44
45 #define AAN_Q1_FIX (1402911301)/* S1.30 1402911301 1.306563*/
46
47 /** Scales x by y bits to the right, adding a rounding factor.
48 */
49 #ifndef SCALE
50 #define SCALE(x, y) (((x) + (1 <<((y)-1))) >> (y))
51 #endif
52
53 /**
54 * Default C language implementation of a 32x32->32 multiply. This function may
55 * be replaced by a platform-specific version for speed.
56 *
57 * @param u A signed 32-bit multiplicand
58 * @param v A signed 32-bit multiplier
59
60 * @return A signed 32-bit value corresponding to the 32 most significant bits
61 * of the 64-bit product of u and v.
62 */
63 INLINE OI_INT32 default_mul_32s_32s_hi(OI_INT32 u, OI_INT32 v);
default_mul_32s_32s_hi(OI_INT32 u,OI_INT32 v)64 INLINE OI_INT32 default_mul_32s_32s_hi(OI_INT32 u, OI_INT32 v)
65 {
66 OI_UINT32 u0, v0;
67 OI_INT32 u1, v1, w1, w2, t;
68
69 u0 = u & 0xFFFF; u1 = u >> 16;
70 v0 = v & 0xFFFF; v1 = v >> 16;
71 t = u0*v0;
72 t = (u1*v0) + ((OI_UINT32)t >> 16);
73 w1 = t & 0xFFFF;
74 w2 = t >> 16;
75 w1 = (u0*v1) + w1;
76 return (u1*v1) + w2 + (w1 >> 16);
77 }
78
79 #define MUL_32S_32S_HI(_x, _y) default_mul_32s_32s_hi(_x, _y)
80
81
82 #ifdef DEBUG_DCT
float_dct2_8(float * RESTRICT out,OI_INT32 const * RESTRICT in)83 PRIVATE void float_dct2_8(float * RESTRICT out, OI_INT32 const *RESTRICT in)
84 {
85 #define FIX(x,bits) (((int)floor(0.5f+((x)*((float)(1<<bits)))))/((float)(1<<bits)))
86 #define FLOAT_BUTTERFLY(x,y) x += y; y = x - (y*2); OI_ASSERT(VALID_INT32(x)); OI_ASSERT(VALID_INT32(y));
87 #define FLOAT_MULT_DCT(K, sample) (FIX(K,20) * sample)
88 #define FLOAT_SCALE(x, y) (((x) / (double)(1 << (y))))
89
90 double L00,L01,L02,L03,L04,L05,L06,L07;
91 double L25;
92
93 double in0,in1,in2,in3;
94 double in4,in5,in6,in7;
95
96 in0 = FLOAT_SCALE(in[0], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in0));
97 in1 = FLOAT_SCALE(in[1], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in1));
98 in2 = FLOAT_SCALE(in[2], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in2));
99 in3 = FLOAT_SCALE(in[3], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in3));
100 in4 = FLOAT_SCALE(in[4], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in4));
101 in5 = FLOAT_SCALE(in[5], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in5));
102 in6 = FLOAT_SCALE(in[6], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in6));
103 in7 = FLOAT_SCALE(in[7], DCTII_8_SHIFT_IN); OI_ASSERT(VALID_INT32(in7));
104
105 L00 = (in0 + in7); OI_ASSERT(VALID_INT32(L00));
106 L01 = (in1 + in6); OI_ASSERT(VALID_INT32(L01));
107 L02 = (in2 + in5); OI_ASSERT(VALID_INT32(L02));
108 L03 = (in3 + in4); OI_ASSERT(VALID_INT32(L03));
109
110 L04 = (in3 - in4); OI_ASSERT(VALID_INT32(L04));
111 L05 = (in2 - in5); OI_ASSERT(VALID_INT32(L05));
112 L06 = (in1 - in6); OI_ASSERT(VALID_INT32(L06));
113 L07 = (in0 - in7); OI_ASSERT(VALID_INT32(L07));
114
115 FLOAT_BUTTERFLY(L00, L03);
116 FLOAT_BUTTERFLY(L01, L02);
117
118 L02 += L03; OI_ASSERT(VALID_INT32(L02));
119
120 L02 = FLOAT_MULT_DCT(AAN_C4_FLOAT, L02); OI_ASSERT(VALID_INT32(L02));
121
122 FLOAT_BUTTERFLY(L00, L01);
123
124 out[0] = (float)FLOAT_SCALE(L00, DCTII_8_SHIFT_0); OI_ASSERT(VALID_INT16(out[0]));
125 out[4] = (float)FLOAT_SCALE(L01, DCTII_8_SHIFT_4); OI_ASSERT(VALID_INT16(out[4]));
126
127 FLOAT_BUTTERFLY(L03, L02);
128 out[6] = (float)FLOAT_SCALE(L02, DCTII_8_SHIFT_6); OI_ASSERT(VALID_INT16(out[6]));
129 out[2] = (float)FLOAT_SCALE(L03, DCTII_8_SHIFT_2); OI_ASSERT(VALID_INT16(out[2]));
130
131 L04 += L05; OI_ASSERT(VALID_INT32(L04));
132 L05 += L06; OI_ASSERT(VALID_INT32(L05));
133 L06 += L07; OI_ASSERT(VALID_INT32(L06));
134
135 L04/=2;
136 L05/=2;
137 L06/=2;
138 L07/=2;
139
140 L05 = FLOAT_MULT_DCT(AAN_C4_FLOAT, L05); OI_ASSERT(VALID_INT32(L05));
141
142 L25 = L06 - L04; OI_ASSERT(VALID_INT32(L25));
143 L25 = FLOAT_MULT_DCT(AAN_C6_FLOAT, L25); OI_ASSERT(VALID_INT32(L25));
144
145 L04 = FLOAT_MULT_DCT(AAN_Q0_FLOAT, L04); OI_ASSERT(VALID_INT32(L04));
146 L04 -= L25; OI_ASSERT(VALID_INT32(L04));
147
148 L06 = FLOAT_MULT_DCT(AAN_Q1_FLOAT, L06); OI_ASSERT(VALID_INT32(L06));
149 L06 -= L25; OI_ASSERT(VALID_INT32(L25));
150
151 FLOAT_BUTTERFLY(L07, L05);
152
153 FLOAT_BUTTERFLY(L05, L04);
154 out[3] = (float)(FLOAT_SCALE(L04, DCTII_8_SHIFT_3-1)); OI_ASSERT(VALID_INT16(out[3]));
155 out[5] = (float)(FLOAT_SCALE(L05, DCTII_8_SHIFT_5-1)); OI_ASSERT(VALID_INT16(out[5]));
156
157 FLOAT_BUTTERFLY(L07, L06);
158 out[7] = (float)(FLOAT_SCALE(L06, DCTII_8_SHIFT_7-1)); OI_ASSERT(VALID_INT16(out[7]));
159 out[1] = (float)(FLOAT_SCALE(L07, DCTII_8_SHIFT_1-1)); OI_ASSERT(VALID_INT16(out[1]));
160 }
161 #undef BUTTERFLY
162 #endif
163
164
165 /*
166 * This function calculates the AAN DCT. Its inputs are in S16.15 format, as
167 * returned by OI_SBC_Dequant. In practice, abs(in[x]) < 52429.0 / 1.38
168 * (1244918057 integer). The function it computes is an approximation to the array defined
169 * by:
170 *
171 * diag(aan_s) * AAN= C2
172 *
173 * or
174 *
175 * AAN = diag(1/aan_s) * C2
176 *
177 * where C2 is as it is defined in the comment at the head of this file, and
178 *
179 * aan_s[i] = aan_s = 1/(2*cos(i*pi/16)) with i = 1..7, aan_s[0] = 1;
180 *
181 * aan_s[i] = [ 1.000 0.510 0.541 0.601 0.707 0.900 1.307 2.563 ]
182 *
183 * The output ranges are shown as follows:
184 *
185 * Let Y[0..7] = AAN * X[0..7]
186 *
187 * Without loss of generality, assume the input vector X consists of elements
188 * between -1 and 1. The maximum possible value of a given output element occurs
189 * with some particular combination of input vector elements each of which is -1
190 * or 1. Consider the computation of Y[i]. Y[i] = sum t=0..7 of AAN[t,i]*X[i]. Y is
191 * maximized if the sign of X[i] matches the sign of AAN[t,i], ensuring a
192 * positive contribution to the sum. Equivalently, one may simply sum
193 * abs(AAN)[t,i] over t to get the maximum possible value of Y[i].
194 *
195 * This yields approximately [8.00 10.05 9.66 8.52 8.00 5.70 4.00 2.00]
196 *
197 * Given the maximum magnitude sensible input value of +/-37992, this yields the
198 * following vector of maximum output magnitudes:
199 *
200 * [ 303936 381820 367003 323692 303936 216555 151968 75984 ]
201 *
202 * Ultimately, these values must fit into 16 bit signed integers, so they must
203 * be scaled. A non-uniform scaling helps maximize the kept precision. The
204 * relative number of extra bits of precision maintainable with respect to the
205 * largest value is given here:
206 *
207 * [ 0 0 0 0 0 0 1 2 ]
208 *
209 */
210 PRIVATE void dct2_8(SBC_BUFFER_T * RESTRICT out, OI_INT32 const *RESTRICT in);
dct2_8(SBC_BUFFER_T * RESTRICT out,OI_INT32 const * RESTRICT in)211 PRIVATE void dct2_8(SBC_BUFFER_T * RESTRICT out, OI_INT32 const *RESTRICT in)
212 {
213 #define BUTTERFLY(x,y) x += y; y = x - (y<<1);
214 #define FIX_MULT_DCT(K, x) (MUL_32S_32S_HI(K,x)<<2)
215
216 OI_INT32 L00,L01,L02,L03,L04,L05,L06,L07;
217 OI_INT32 L25;
218
219 OI_INT32 in0,in1,in2,in3;
220 OI_INT32 in4,in5,in6,in7;
221
222 #if DCTII_8_SHIFT_IN != 0
223 in0 = SCALE(in[0], DCTII_8_SHIFT_IN);
224 in1 = SCALE(in[1], DCTII_8_SHIFT_IN);
225 in2 = SCALE(in[2], DCTII_8_SHIFT_IN);
226 in3 = SCALE(in[3], DCTII_8_SHIFT_IN);
227 in4 = SCALE(in[4], DCTII_8_SHIFT_IN);
228 in5 = SCALE(in[5], DCTII_8_SHIFT_IN);
229 in6 = SCALE(in[6], DCTII_8_SHIFT_IN);
230 in7 = SCALE(in[7], DCTII_8_SHIFT_IN);
231 #else
232 in0 = in[0];
233 in1 = in[1];
234 in2 = in[2];
235 in3 = in[3];
236 in4 = in[4];
237 in5 = in[5];
238 in6 = in[6];
239 in7 = in[7];
240 #endif
241
242 L00 = in0 + in7;
243 L01 = in1 + in6;
244 L02 = in2 + in5;
245 L03 = in3 + in4;
246
247 L04 = in3 - in4;
248 L05 = in2 - in5;
249 L06 = in1 - in6;
250 L07 = in0 - in7;
251
252 BUTTERFLY(L00, L03);
253 BUTTERFLY(L01, L02);
254
255 L02 += L03;
256
257 L02 = FIX_MULT_DCT(AAN_C4_FIX, L02);
258
259 BUTTERFLY(L00, L01);
260
261 out[0] = (OI_INT16)SCALE(L00, DCTII_8_SHIFT_0);
262 out[4] = (OI_INT16)SCALE(L01, DCTII_8_SHIFT_4);
263
264 BUTTERFLY(L03, L02);
265 out[6] = (OI_INT16)SCALE(L02, DCTII_8_SHIFT_6);
266 out[2] = (OI_INT16)SCALE(L03, DCTII_8_SHIFT_2);
267
268 L04 += L05;
269 L05 += L06;
270 L06 += L07;
271
272 L04/=2;
273 L05/=2;
274 L06/=2;
275 L07/=2;
276
277 L05 = FIX_MULT_DCT(AAN_C4_FIX, L05);
278
279 L25 = L06 - L04;
280 L25 = FIX_MULT_DCT(AAN_C6_FIX, L25);
281
282 L04 = FIX_MULT_DCT(AAN_Q0_FIX, L04);
283 L04 -= L25;
284
285 L06 = FIX_MULT_DCT(AAN_Q1_FIX, L06);
286 L06 -= L25;
287
288 BUTTERFLY(L07, L05);
289
290 BUTTERFLY(L05, L04);
291 out[3] = (OI_INT16)SCALE(L04, DCTII_8_SHIFT_3-1);
292 out[5] = (OI_INT16)SCALE(L05, DCTII_8_SHIFT_5-1);
293
294 BUTTERFLY(L07, L06);
295 out[7] = (OI_INT16)SCALE(L06, DCTII_8_SHIFT_7-1);
296 out[1] = (OI_INT16)SCALE(L07, DCTII_8_SHIFT_1-1);
297 #undef BUTTERFLY
298
299 #ifdef DEBUG_DCT
300 {
301 float float_out[8];
302 float_dct2_8(float_out, in);
303 }
304 #endif
305 }
306
307 /**@}*/
308