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 iLBC Speech Coder ANSI-C Source Code
14
15 WebRtcIlbcfix_CbMemEnergyCalc.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/defines.h"
20
21 /* Compute the energy of the rest of the cb memory
22 * by step wise adding and subtracting the next
23 * sample and the last sample respectively */
WebRtcIlbcfix_CbMemEnergyCalc(int32_t energy,size_t range,int16_t * ppi,int16_t * ppo,int16_t * energyW16,int16_t * energyShifts,int scale,size_t base_size)24 void WebRtcIlbcfix_CbMemEnergyCalc(
25 int32_t energy, /* (i) input start energy */
26 size_t range, /* (i) number of iterations */
27 int16_t *ppi, /* (i) input pointer 1 */
28 int16_t *ppo, /* (i) input pointer 2 */
29 int16_t *energyW16, /* (o) Energy in the CB vectors */
30 int16_t *energyShifts, /* (o) Shift value of the energy */
31 int scale, /* (i) The scaling of all energy values */
32 size_t base_size /* (i) Index to where energy values should be stored */
33 )
34 {
35 size_t j;
36 int16_t shft;
37 int32_t tmp;
38 int16_t *eSh_ptr;
39 int16_t *eW16_ptr;
40
41
42 eSh_ptr = &energyShifts[1+base_size];
43 eW16_ptr = &energyW16[1+base_size];
44
45 for (j = 0; j + 1 < range; j++) {
46
47 /* Calculate next energy by a +/-
48 operation on the edge samples */
49 tmp = (*ppi) * (*ppi) - (*ppo) * (*ppo);
50 energy += tmp >> scale;
51 energy = WEBRTC_SPL_MAX(energy, 0);
52
53 ppi--;
54 ppo--;
55
56 /* Normalize the energy into a int16_t and store
57 the number of shifts */
58
59 shft = (int16_t)WebRtcSpl_NormW32(energy);
60 *eSh_ptr++ = shft;
61
62 tmp = energy << shft;
63 *eW16_ptr++ = (int16_t)(tmp >> 16);
64 }
65 }
66