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_GetSyncSeq.c
16
17******************************************************************/
18
19#include "defines.h"
20#include "constants.h"
21#include "refiner.h"
22#include "nearest_neighbor.h"
23
24/*----------------------------------------------------------------*
25 * get the pitch-synchronous sample sequence
26 *---------------------------------------------------------------*/
27
28void WebRtcIlbcfix_GetSyncSeq(
29    int16_t *idata,   /* (i) original data */
30    size_t idatal,   /* (i) dimension of data */
31    size_t centerStartPos, /* (i) where current block starts */
32    size_t *period,   /* (i) rough-pitch-period array       (Q-2) */
33    const size_t *plocs, /* (i) where periods of period array are taken (Q-2) */
34    size_t periodl,   /* (i) dimension period array */
35    size_t hl,    /* (i) 2*hl+1 is the number of sequences */
36    int16_t *surround  /* (i/o) The contribution from this sequence
37                                summed with earlier contributions */
38                              ){
39  size_t i, centerEndPos, q;
40  /* Stack based */
41  size_t lagBlock[2 * ENH_HL + 1];
42  size_t blockStartPos[2 * ENH_HL + 1]; /* The position to search around (Q2) */
43  size_t plocs2[ENH_PLOCSL];
44
45  centerEndPos = centerStartPos + ENH_BLOCKL - 1;
46
47  /* present (find predicted lag from this position) */
48
49  WebRtcIlbcfix_NearestNeighbor(lagBlock + hl,
50                                plocs,
51                                2 * (centerStartPos + centerEndPos),
52                                periodl);
53
54  blockStartPos[hl] = 4 * centerStartPos;
55
56  /* past (find predicted position and perform a refined
57     search to find the best sequence) */
58
59  for (q = hl; q > 0; q--) {
60    size_t qq = q - 1;
61    size_t period_q = period[lagBlock[q]];
62    /* Stop if this sequence would be outside the buffer; that means all
63       further-past sequences would also be outside the buffer. */
64    if (blockStartPos[q] < period_q + (4 * ENH_OVERHANG))
65      break;
66    blockStartPos[qq] = blockStartPos[q] - period_q;
67
68    size_t value = blockStartPos[qq] + 4 * ENH_BLOCKL_HALF;
69    value = (value > period_q) ? (value - period_q) : 0;
70    WebRtcIlbcfix_NearestNeighbor(lagBlock + qq, plocs, value, periodl);
71
72    /* Find the best possible sequence in the 4 times upsampled
73        domain around blockStartPos+q */
74    WebRtcIlbcfix_Refiner(blockStartPos + qq, idata, idatal, centerStartPos,
75                          blockStartPos[qq], surround,
76                          WebRtcIlbcfix_kEnhWt[qq]);
77  }
78
79  /* future (find predicted position and perform a refined
80     search to find the best sequence) */
81
82  for (i = 0; i < periodl; i++) {
83    plocs2[i] = plocs[i] - period[i];
84  }
85
86  for (q = hl + 1; q <= (2 * hl); q++) {
87
88    WebRtcIlbcfix_NearestNeighbor(
89        lagBlock + q,
90        plocs2,
91        blockStartPos[q - 1] + 4 * ENH_BLOCKL_HALF,
92        periodl);
93
94    blockStartPos[q]=blockStartPos[q-1]+period[lagBlock[q]];
95
96    if (blockStartPos[q] + 4 * (ENH_BLOCKL + ENH_OVERHANG) < 4 * idatal) {
97
98      /* Find the best possible sequence in the 4 times upsampled
99         domain around blockStartPos+q */
100      WebRtcIlbcfix_Refiner(blockStartPos + q, idata, idatal, centerStartPos,
101                            blockStartPos[q], surround,
102                            WebRtcIlbcfix_kEnhWt[2 * hl - q]);
103
104    } else {
105      /* Don't add anything since this sequence would
106         be outside the buffer */
107    }
108  }
109}
110