1 /*
2  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 
12 /*
13  * This file contains the resampling functions for 22 kHz.
14  * The description header can be found in signal_processing_library.h
15  *
16  */
17 
18 #include "signal_processing_library.h"
19 #include "resample_by_2_internal.h"
20 
21 // Declaration of internally used functions
22 static void WebRtcSpl_32khzTo22khzIntToShort(const WebRtc_Word32 *In, WebRtc_Word16 *Out,
23                                              const WebRtc_Word32 K);
24 
25 void WebRtcSpl_32khzTo22khzIntToInt(const WebRtc_Word32 *In, WebRtc_Word32 *Out,
26                                     const WebRtc_Word32 K);
27 
28 // interpolation coefficients
29 static const WebRtc_Word16 kCoefficients32To22[5][9] = {
30         {127, -712,  2359, -6333, 23456, 16775, -3695,  945, -154},
31         {-39,  230,  -830,  2785, 32366, -2324,   760, -218,   38},
32         {117, -663,  2222, -6133, 26634, 13070, -3174,  831, -137},
33         {-77,  457, -1677,  5958, 31175, -4136,  1405, -408,   71},
34         { 98, -560,  1900, -5406, 29240,  9423, -2480,  663, -110}
35 };
36 
37 //////////////////////
38 // 22 kHz -> 16 kHz //
39 //////////////////////
40 
41 // number of subblocks; options: 1, 2, 4, 5, 10
42 #define SUB_BLOCKS_22_16    5
43 
44 // 22 -> 16 resampler
WebRtcSpl_Resample22khzTo16khz(const WebRtc_Word16 * in,WebRtc_Word16 * out,WebRtcSpl_State22khzTo16khz * state,WebRtc_Word32 * tmpmem)45 void WebRtcSpl_Resample22khzTo16khz(const WebRtc_Word16* in, WebRtc_Word16* out,
46                                     WebRtcSpl_State22khzTo16khz* state, WebRtc_Word32* tmpmem)
47 {
48     int k;
49 
50     // process two blocks of 10/SUB_BLOCKS_22_16 ms (to reduce temp buffer size)
51     for (k = 0; k < SUB_BLOCKS_22_16; k++)
52     {
53         ///// 22 --> 44 /////
54         // WebRtc_Word16  in[220/SUB_BLOCKS_22_16]
55         // WebRtc_Word32 out[440/SUB_BLOCKS_22_16]
56         /////
57         WebRtcSpl_UpBy2ShortToInt(in, 220 / SUB_BLOCKS_22_16, tmpmem + 16, state->S_22_44);
58 
59         ///// 44 --> 32 /////
60         // WebRtc_Word32  in[440/SUB_BLOCKS_22_16]
61         // WebRtc_Word32 out[320/SUB_BLOCKS_22_16]
62         /////
63         // copy state to and from input array
64         tmpmem[8] = state->S_44_32[0];
65         tmpmem[9] = state->S_44_32[1];
66         tmpmem[10] = state->S_44_32[2];
67         tmpmem[11] = state->S_44_32[3];
68         tmpmem[12] = state->S_44_32[4];
69         tmpmem[13] = state->S_44_32[5];
70         tmpmem[14] = state->S_44_32[6];
71         tmpmem[15] = state->S_44_32[7];
72         state->S_44_32[0] = tmpmem[440 / SUB_BLOCKS_22_16 + 8];
73         state->S_44_32[1] = tmpmem[440 / SUB_BLOCKS_22_16 + 9];
74         state->S_44_32[2] = tmpmem[440 / SUB_BLOCKS_22_16 + 10];
75         state->S_44_32[3] = tmpmem[440 / SUB_BLOCKS_22_16 + 11];
76         state->S_44_32[4] = tmpmem[440 / SUB_BLOCKS_22_16 + 12];
77         state->S_44_32[5] = tmpmem[440 / SUB_BLOCKS_22_16 + 13];
78         state->S_44_32[6] = tmpmem[440 / SUB_BLOCKS_22_16 + 14];
79         state->S_44_32[7] = tmpmem[440 / SUB_BLOCKS_22_16 + 15];
80 
81         WebRtcSpl_Resample44khzTo32khz(tmpmem + 8, tmpmem, 40 / SUB_BLOCKS_22_16);
82 
83         ///// 32 --> 16 /////
84         // WebRtc_Word32  in[320/SUB_BLOCKS_22_16]
85         // WebRtc_Word32 out[160/SUB_BLOCKS_22_16]
86         /////
87         WebRtcSpl_DownBy2IntToShort(tmpmem, 320 / SUB_BLOCKS_22_16, out, state->S_32_16);
88 
89         // move input/output pointers 10/SUB_BLOCKS_22_16 ms seconds ahead
90         in += 220 / SUB_BLOCKS_22_16;
91         out += 160 / SUB_BLOCKS_22_16;
92     }
93 }
94 
95 // initialize state of 22 -> 16 resampler
WebRtcSpl_ResetResample22khzTo16khz(WebRtcSpl_State22khzTo16khz * state)96 void WebRtcSpl_ResetResample22khzTo16khz(WebRtcSpl_State22khzTo16khz* state)
97 {
98     int k;
99     for (k = 0; k < 8; k++)
100     {
101         state->S_22_44[k] = 0;
102         state->S_44_32[k] = 0;
103         state->S_32_16[k] = 0;
104     }
105 }
106 
107 //////////////////////
108 // 16 kHz -> 22 kHz //
109 //////////////////////
110 
111 // number of subblocks; options: 1, 2, 4, 5, 10
112 #define SUB_BLOCKS_16_22    4
113 
114 // 16 -> 22 resampler
WebRtcSpl_Resample16khzTo22khz(const WebRtc_Word16 * in,WebRtc_Word16 * out,WebRtcSpl_State16khzTo22khz * state,WebRtc_Word32 * tmpmem)115 void WebRtcSpl_Resample16khzTo22khz(const WebRtc_Word16* in, WebRtc_Word16* out,
116                                     WebRtcSpl_State16khzTo22khz* state, WebRtc_Word32* tmpmem)
117 {
118     int k;
119 
120     // process two blocks of 10/SUB_BLOCKS_16_22 ms (to reduce temp buffer size)
121     for (k = 0; k < SUB_BLOCKS_16_22; k++)
122     {
123         ///// 16 --> 32 /////
124         // WebRtc_Word16  in[160/SUB_BLOCKS_16_22]
125         // WebRtc_Word32 out[320/SUB_BLOCKS_16_22]
126         /////
127         WebRtcSpl_UpBy2ShortToInt(in, 160 / SUB_BLOCKS_16_22, tmpmem + 8, state->S_16_32);
128 
129         ///// 32 --> 22 /////
130         // WebRtc_Word32  in[320/SUB_BLOCKS_16_22]
131         // WebRtc_Word32 out[220/SUB_BLOCKS_16_22]
132         /////
133         // copy state to and from input array
134         tmpmem[0] = state->S_32_22[0];
135         tmpmem[1] = state->S_32_22[1];
136         tmpmem[2] = state->S_32_22[2];
137         tmpmem[3] = state->S_32_22[3];
138         tmpmem[4] = state->S_32_22[4];
139         tmpmem[5] = state->S_32_22[5];
140         tmpmem[6] = state->S_32_22[6];
141         tmpmem[7] = state->S_32_22[7];
142         state->S_32_22[0] = tmpmem[320 / SUB_BLOCKS_16_22];
143         state->S_32_22[1] = tmpmem[320 / SUB_BLOCKS_16_22 + 1];
144         state->S_32_22[2] = tmpmem[320 / SUB_BLOCKS_16_22 + 2];
145         state->S_32_22[3] = tmpmem[320 / SUB_BLOCKS_16_22 + 3];
146         state->S_32_22[4] = tmpmem[320 / SUB_BLOCKS_16_22 + 4];
147         state->S_32_22[5] = tmpmem[320 / SUB_BLOCKS_16_22 + 5];
148         state->S_32_22[6] = tmpmem[320 / SUB_BLOCKS_16_22 + 6];
149         state->S_32_22[7] = tmpmem[320 / SUB_BLOCKS_16_22 + 7];
150 
151         WebRtcSpl_32khzTo22khzIntToShort(tmpmem, out, 20 / SUB_BLOCKS_16_22);
152 
153         // move input/output pointers 10/SUB_BLOCKS_16_22 ms seconds ahead
154         in += 160 / SUB_BLOCKS_16_22;
155         out += 220 / SUB_BLOCKS_16_22;
156     }
157 }
158 
159 // initialize state of 16 -> 22 resampler
WebRtcSpl_ResetResample16khzTo22khz(WebRtcSpl_State16khzTo22khz * state)160 void WebRtcSpl_ResetResample16khzTo22khz(WebRtcSpl_State16khzTo22khz* state)
161 {
162     int k;
163     for (k = 0; k < 8; k++)
164     {
165         state->S_16_32[k] = 0;
166         state->S_32_22[k] = 0;
167     }
168 }
169 
170 //////////////////////
171 // 22 kHz ->  8 kHz //
172 //////////////////////
173 
174 // number of subblocks; options: 1, 2, 5, 10
175 #define SUB_BLOCKS_22_8     2
176 
177 // 22 -> 8 resampler
WebRtcSpl_Resample22khzTo8khz(const WebRtc_Word16 * in,WebRtc_Word16 * out,WebRtcSpl_State22khzTo8khz * state,WebRtc_Word32 * tmpmem)178 void WebRtcSpl_Resample22khzTo8khz(const WebRtc_Word16* in, WebRtc_Word16* out,
179                                    WebRtcSpl_State22khzTo8khz* state, WebRtc_Word32* tmpmem)
180 {
181     int k;
182 
183     // process two blocks of 10/SUB_BLOCKS_22_8 ms (to reduce temp buffer size)
184     for (k = 0; k < SUB_BLOCKS_22_8; k++)
185     {
186         ///// 22 --> 22 lowpass /////
187         // WebRtc_Word16  in[220/SUB_BLOCKS_22_8]
188         // WebRtc_Word32 out[220/SUB_BLOCKS_22_8]
189         /////
190         WebRtcSpl_LPBy2ShortToInt(in, 220 / SUB_BLOCKS_22_8, tmpmem + 16, state->S_22_22);
191 
192         ///// 22 --> 16 /////
193         // WebRtc_Word32  in[220/SUB_BLOCKS_22_8]
194         // WebRtc_Word32 out[160/SUB_BLOCKS_22_8]
195         /////
196         // copy state to and from input array
197         tmpmem[8] = state->S_22_16[0];
198         tmpmem[9] = state->S_22_16[1];
199         tmpmem[10] = state->S_22_16[2];
200         tmpmem[11] = state->S_22_16[3];
201         tmpmem[12] = state->S_22_16[4];
202         tmpmem[13] = state->S_22_16[5];
203         tmpmem[14] = state->S_22_16[6];
204         tmpmem[15] = state->S_22_16[7];
205         state->S_22_16[0] = tmpmem[220 / SUB_BLOCKS_22_8 + 8];
206         state->S_22_16[1] = tmpmem[220 / SUB_BLOCKS_22_8 + 9];
207         state->S_22_16[2] = tmpmem[220 / SUB_BLOCKS_22_8 + 10];
208         state->S_22_16[3] = tmpmem[220 / SUB_BLOCKS_22_8 + 11];
209         state->S_22_16[4] = tmpmem[220 / SUB_BLOCKS_22_8 + 12];
210         state->S_22_16[5] = tmpmem[220 / SUB_BLOCKS_22_8 + 13];
211         state->S_22_16[6] = tmpmem[220 / SUB_BLOCKS_22_8 + 14];
212         state->S_22_16[7] = tmpmem[220 / SUB_BLOCKS_22_8 + 15];
213 
214         WebRtcSpl_Resample44khzTo32khz(tmpmem + 8, tmpmem, 20 / SUB_BLOCKS_22_8);
215 
216         ///// 16 --> 8 /////
217         // WebRtc_Word32 in[160/SUB_BLOCKS_22_8]
218         // WebRtc_Word32 out[80/SUB_BLOCKS_22_8]
219         /////
220         WebRtcSpl_DownBy2IntToShort(tmpmem, 160 / SUB_BLOCKS_22_8, out, state->S_16_8);
221 
222         // move input/output pointers 10/SUB_BLOCKS_22_8 ms seconds ahead
223         in += 220 / SUB_BLOCKS_22_8;
224         out += 80 / SUB_BLOCKS_22_8;
225     }
226 }
227 
228 // initialize state of 22 -> 8 resampler
WebRtcSpl_ResetResample22khzTo8khz(WebRtcSpl_State22khzTo8khz * state)229 void WebRtcSpl_ResetResample22khzTo8khz(WebRtcSpl_State22khzTo8khz* state)
230 {
231     int k;
232     for (k = 0; k < 8; k++)
233     {
234         state->S_22_22[k] = 0;
235         state->S_22_22[k + 8] = 0;
236         state->S_22_16[k] = 0;
237         state->S_16_8[k] = 0;
238     }
239 }
240 
241 //////////////////////
242 //  8 kHz -> 22 kHz //
243 //////////////////////
244 
245 // number of subblocks; options: 1, 2, 5, 10
246 #define SUB_BLOCKS_8_22     2
247 
248 // 8 -> 22 resampler
WebRtcSpl_Resample8khzTo22khz(const WebRtc_Word16 * in,WebRtc_Word16 * out,WebRtcSpl_State8khzTo22khz * state,WebRtc_Word32 * tmpmem)249 void WebRtcSpl_Resample8khzTo22khz(const WebRtc_Word16* in, WebRtc_Word16* out,
250                                    WebRtcSpl_State8khzTo22khz* state, WebRtc_Word32* tmpmem)
251 {
252     int k;
253 
254     // process two blocks of 10/SUB_BLOCKS_8_22 ms (to reduce temp buffer size)
255     for (k = 0; k < SUB_BLOCKS_8_22; k++)
256     {
257         ///// 8 --> 16 /////
258         // WebRtc_Word16  in[80/SUB_BLOCKS_8_22]
259         // WebRtc_Word32 out[160/SUB_BLOCKS_8_22]
260         /////
261         WebRtcSpl_UpBy2ShortToInt(in, 80 / SUB_BLOCKS_8_22, tmpmem + 18, state->S_8_16);
262 
263         ///// 16 --> 11 /////
264         // WebRtc_Word32  in[160/SUB_BLOCKS_8_22]
265         // WebRtc_Word32 out[110/SUB_BLOCKS_8_22]
266         /////
267         // copy state to and from input array
268         tmpmem[10] = state->S_16_11[0];
269         tmpmem[11] = state->S_16_11[1];
270         tmpmem[12] = state->S_16_11[2];
271         tmpmem[13] = state->S_16_11[3];
272         tmpmem[14] = state->S_16_11[4];
273         tmpmem[15] = state->S_16_11[5];
274         tmpmem[16] = state->S_16_11[6];
275         tmpmem[17] = state->S_16_11[7];
276         state->S_16_11[0] = tmpmem[160 / SUB_BLOCKS_8_22 + 10];
277         state->S_16_11[1] = tmpmem[160 / SUB_BLOCKS_8_22 + 11];
278         state->S_16_11[2] = tmpmem[160 / SUB_BLOCKS_8_22 + 12];
279         state->S_16_11[3] = tmpmem[160 / SUB_BLOCKS_8_22 + 13];
280         state->S_16_11[4] = tmpmem[160 / SUB_BLOCKS_8_22 + 14];
281         state->S_16_11[5] = tmpmem[160 / SUB_BLOCKS_8_22 + 15];
282         state->S_16_11[6] = tmpmem[160 / SUB_BLOCKS_8_22 + 16];
283         state->S_16_11[7] = tmpmem[160 / SUB_BLOCKS_8_22 + 17];
284 
285         WebRtcSpl_32khzTo22khzIntToInt(tmpmem + 10, tmpmem, 10 / SUB_BLOCKS_8_22);
286 
287         ///// 11 --> 22 /////
288         // WebRtc_Word32  in[110/SUB_BLOCKS_8_22]
289         // WebRtc_Word16 out[220/SUB_BLOCKS_8_22]
290         /////
291         WebRtcSpl_UpBy2IntToShort(tmpmem, 110 / SUB_BLOCKS_8_22, out, state->S_11_22);
292 
293         // move input/output pointers 10/SUB_BLOCKS_8_22 ms seconds ahead
294         in += 80 / SUB_BLOCKS_8_22;
295         out += 220 / SUB_BLOCKS_8_22;
296     }
297 }
298 
299 // initialize state of 8 -> 22 resampler
WebRtcSpl_ResetResample8khzTo22khz(WebRtcSpl_State8khzTo22khz * state)300 void WebRtcSpl_ResetResample8khzTo22khz(WebRtcSpl_State8khzTo22khz* state)
301 {
302     int k;
303     for (k = 0; k < 8; k++)
304     {
305         state->S_8_16[k] = 0;
306         state->S_16_11[k] = 0;
307         state->S_11_22[k] = 0;
308     }
309 }
310 
311 // compute two inner-products and store them to output array
WebRtcSpl_DotProdIntToInt(const WebRtc_Word32 * in1,const WebRtc_Word32 * in2,const WebRtc_Word16 * coef_ptr,WebRtc_Word32 * out1,WebRtc_Word32 * out2)312 static void WebRtcSpl_DotProdIntToInt(const WebRtc_Word32* in1, const WebRtc_Word32* in2,
313                                       const WebRtc_Word16* coef_ptr, WebRtc_Word32* out1,
314                                       WebRtc_Word32* out2)
315 {
316     WebRtc_Word32 tmp1 = 16384;
317     WebRtc_Word32 tmp2 = 16384;
318     WebRtc_Word16 coef;
319 
320     coef = coef_ptr[0];
321     tmp1 += coef * in1[0];
322     tmp2 += coef * in2[-0];
323 
324     coef = coef_ptr[1];
325     tmp1 += coef * in1[1];
326     tmp2 += coef * in2[-1];
327 
328     coef = coef_ptr[2];
329     tmp1 += coef * in1[2];
330     tmp2 += coef * in2[-2];
331 
332     coef = coef_ptr[3];
333     tmp1 += coef * in1[3];
334     tmp2 += coef * in2[-3];
335 
336     coef = coef_ptr[4];
337     tmp1 += coef * in1[4];
338     tmp2 += coef * in2[-4];
339 
340     coef = coef_ptr[5];
341     tmp1 += coef * in1[5];
342     tmp2 += coef * in2[-5];
343 
344     coef = coef_ptr[6];
345     tmp1 += coef * in1[6];
346     tmp2 += coef * in2[-6];
347 
348     coef = coef_ptr[7];
349     tmp1 += coef * in1[7];
350     tmp2 += coef * in2[-7];
351 
352     coef = coef_ptr[8];
353     *out1 = tmp1 + coef * in1[8];
354     *out2 = tmp2 + coef * in2[-8];
355 }
356 
357 // compute two inner-products and store them to output array
WebRtcSpl_DotProdIntToShort(const WebRtc_Word32 * in1,const WebRtc_Word32 * in2,const WebRtc_Word16 * coef_ptr,WebRtc_Word16 * out1,WebRtc_Word16 * out2)358 static void WebRtcSpl_DotProdIntToShort(const WebRtc_Word32* in1, const WebRtc_Word32* in2,
359                                         const WebRtc_Word16* coef_ptr, WebRtc_Word16* out1,
360                                         WebRtc_Word16* out2)
361 {
362     WebRtc_Word32 tmp1 = 16384;
363     WebRtc_Word32 tmp2 = 16384;
364     WebRtc_Word16 coef;
365 
366     coef = coef_ptr[0];
367     tmp1 += coef * in1[0];
368     tmp2 += coef * in2[-0];
369 
370     coef = coef_ptr[1];
371     tmp1 += coef * in1[1];
372     tmp2 += coef * in2[-1];
373 
374     coef = coef_ptr[2];
375     tmp1 += coef * in1[2];
376     tmp2 += coef * in2[-2];
377 
378     coef = coef_ptr[3];
379     tmp1 += coef * in1[3];
380     tmp2 += coef * in2[-3];
381 
382     coef = coef_ptr[4];
383     tmp1 += coef * in1[4];
384     tmp2 += coef * in2[-4];
385 
386     coef = coef_ptr[5];
387     tmp1 += coef * in1[5];
388     tmp2 += coef * in2[-5];
389 
390     coef = coef_ptr[6];
391     tmp1 += coef * in1[6];
392     tmp2 += coef * in2[-6];
393 
394     coef = coef_ptr[7];
395     tmp1 += coef * in1[7];
396     tmp2 += coef * in2[-7];
397 
398     coef = coef_ptr[8];
399     tmp1 += coef * in1[8];
400     tmp2 += coef * in2[-8];
401 
402     // scale down, round and saturate
403     tmp1 >>= 15;
404     if (tmp1 > (WebRtc_Word32)0x00007FFF)
405         tmp1 = 0x00007FFF;
406     if (tmp1 < (WebRtc_Word32)0xFFFF8000)
407         tmp1 = 0xFFFF8000;
408     tmp2 >>= 15;
409     if (tmp2 > (WebRtc_Word32)0x00007FFF)
410         tmp2 = 0x00007FFF;
411     if (tmp2 < (WebRtc_Word32)0xFFFF8000)
412         tmp2 = 0xFFFF8000;
413     *out1 = (WebRtc_Word16)tmp1;
414     *out2 = (WebRtc_Word16)tmp2;
415 }
416 
417 //   Resampling ratio: 11/16
418 // input:  WebRtc_Word32 (normalized, not saturated) :: size 16 * K
419 // output: WebRtc_Word32 (shifted 15 positions to the left, + offset 16384) :: size 11 * K
420 //      K: Number of blocks
421 
WebRtcSpl_32khzTo22khzIntToInt(const WebRtc_Word32 * In,WebRtc_Word32 * Out,const WebRtc_Word32 K)422 void WebRtcSpl_32khzTo22khzIntToInt(const WebRtc_Word32* In,
423                                     WebRtc_Word32* Out,
424                                     const WebRtc_Word32 K)
425 {
426     /////////////////////////////////////////////////////////////
427     // Filter operation:
428     //
429     // Perform resampling (16 input samples -> 11 output samples);
430     // process in sub blocks of size 16 samples.
431     WebRtc_Word32 m;
432 
433     for (m = 0; m < K; m++)
434     {
435         // first output sample
436         Out[0] = ((WebRtc_Word32)In[3] << 15) + (1 << 14);
437 
438         // sum and accumulate filter coefficients and input samples
439         WebRtcSpl_DotProdIntToInt(&In[0], &In[22], kCoefficients32To22[0], &Out[1], &Out[10]);
440 
441         // sum and accumulate filter coefficients and input samples
442         WebRtcSpl_DotProdIntToInt(&In[2], &In[20], kCoefficients32To22[1], &Out[2], &Out[9]);
443 
444         // sum and accumulate filter coefficients and input samples
445         WebRtcSpl_DotProdIntToInt(&In[3], &In[19], kCoefficients32To22[2], &Out[3], &Out[8]);
446 
447         // sum and accumulate filter coefficients and input samples
448         WebRtcSpl_DotProdIntToInt(&In[5], &In[17], kCoefficients32To22[3], &Out[4], &Out[7]);
449 
450         // sum and accumulate filter coefficients and input samples
451         WebRtcSpl_DotProdIntToInt(&In[6], &In[16], kCoefficients32To22[4], &Out[5], &Out[6]);
452 
453         // update pointers
454         In += 16;
455         Out += 11;
456     }
457 }
458 
459 //   Resampling ratio: 11/16
460 // input:  WebRtc_Word32 (normalized, not saturated) :: size 16 * K
461 // output: WebRtc_Word16 (saturated) :: size 11 * K
462 //      K: Number of blocks
463 
WebRtcSpl_32khzTo22khzIntToShort(const WebRtc_Word32 * In,WebRtc_Word16 * Out,const WebRtc_Word32 K)464 void WebRtcSpl_32khzTo22khzIntToShort(const WebRtc_Word32 *In,
465                                       WebRtc_Word16 *Out,
466                                       const WebRtc_Word32 K)
467 {
468     /////////////////////////////////////////////////////////////
469     // Filter operation:
470     //
471     // Perform resampling (16 input samples -> 11 output samples);
472     // process in sub blocks of size 16 samples.
473     WebRtc_Word32 tmp;
474     WebRtc_Word32 m;
475 
476     for (m = 0; m < K; m++)
477     {
478         // first output sample
479         tmp = In[3];
480         if (tmp > (WebRtc_Word32)0x00007FFF)
481             tmp = 0x00007FFF;
482         if (tmp < (WebRtc_Word32)0xFFFF8000)
483             tmp = 0xFFFF8000;
484         Out[0] = (WebRtc_Word16)tmp;
485 
486         // sum and accumulate filter coefficients and input samples
487         WebRtcSpl_DotProdIntToShort(&In[0], &In[22], kCoefficients32To22[0], &Out[1], &Out[10]);
488 
489         // sum and accumulate filter coefficients and input samples
490         WebRtcSpl_DotProdIntToShort(&In[2], &In[20], kCoefficients32To22[1], &Out[2], &Out[9]);
491 
492         // sum and accumulate filter coefficients and input samples
493         WebRtcSpl_DotProdIntToShort(&In[3], &In[19], kCoefficients32To22[2], &Out[3], &Out[8]);
494 
495         // sum and accumulate filter coefficients and input samples
496         WebRtcSpl_DotProdIntToShort(&In[5], &In[17], kCoefficients32To22[3], &Out[4], &Out[7]);
497 
498         // sum and accumulate filter coefficients and input samples
499         WebRtcSpl_DotProdIntToShort(&In[6], &In[16], kCoefficients32To22[4], &Out[5], &Out[6]);
500 
501         // update pointers
502         In += 16;
503         Out += 11;
504     }
505 }
506