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_Vq4.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/vq4.h"
20
21 #include "modules/audio_coding/codecs/ilbc/constants.h"
22
23 /*----------------------------------------------------------------*
24 * vector quantization
25 *---------------------------------------------------------------*/
26
WebRtcIlbcfix_Vq4(int16_t * Xq,int16_t * index,int16_t * CB,int16_t * X,int16_t n_cb)27 void WebRtcIlbcfix_Vq4(
28 int16_t *Xq, /* quantized vector (Q13) */
29 int16_t *index,
30 int16_t *CB, /* codebook in Q13 */
31 int16_t *X, /* vector to quantize (Q13) */
32 int16_t n_cb
33 ){
34 int16_t i, j;
35 int16_t pos, minindex=0;
36 int16_t tmp;
37 int32_t dist, mindist;
38
39 pos = 0;
40 mindist = WEBRTC_SPL_WORD32_MAX; /* start value */
41
42 /* Find the codebook with the lowest square distance */
43 for (j = 0; j < n_cb; j++) {
44 tmp = X[0] - CB[pos];
45 dist = tmp * tmp;
46 for (i = 1; i < 4; i++) {
47 tmp = X[i] - CB[pos + i];
48 dist += tmp * tmp;
49 }
50
51 if (dist < mindist) {
52 mindist = dist;
53 minindex = j;
54 }
55 pos += 4;
56 }
57
58 /* Store the quantized codebook and the index */
59 for (i = 0; i < 4; i++) {
60 Xq[i] = CB[minindex*4 + i];
61 }
62 *index = minindex;
63 }
64