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_CreateAugmentedVec.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/create_augmented_vec.h"
20
21 #include "common_audio/signal_processing/include/signal_processing_library.h"
22 #include "modules/audio_coding/codecs/ilbc/constants.h"
23 #include "modules/audio_coding/codecs/ilbc/defines.h"
24 #include "rtc_base/sanitizer.h"
25
26 /*----------------------------------------------------------------*
27 * Recreate a specific codebook vector from the augmented part.
28 *
29 *----------------------------------------------------------------*/
30
WebRtcIlbcfix_CreateAugmentedVec(size_t index,const int16_t * buffer,int16_t * cbVec)31 void WebRtcIlbcfix_CreateAugmentedVec(
32 size_t index, /* (i) Index for the augmented vector to be
33 created */
34 const int16_t* buffer, /* (i) Pointer to the end of the codebook memory
35 that is used for creation of the augmented
36 codebook */
37 int16_t* cbVec) { /* (o) The constructed codebook vector */
38 size_t ilow;
39 const int16_t *ppo, *ppi;
40 int16_t cbVecTmp[4];
41 /* Interpolation starts 4 elements before cbVec+index, but must not start
42 outside `cbVec`; clamping interp_len to stay within `cbVec`.
43 */
44 size_t interp_len = WEBRTC_SPL_MIN(index, 4);
45
46 rtc_MsanCheckInitialized(buffer - index - interp_len, sizeof(buffer[0]),
47 index + interp_len);
48
49 ilow = index - interp_len;
50
51 /* copy the first noninterpolated part */
52 ppo = buffer-index;
53 WEBRTC_SPL_MEMCPY_W16(cbVec, ppo, index);
54
55 /* interpolation */
56 ppo = buffer - interp_len;
57 ppi = buffer - index - interp_len;
58
59 /* perform cbVec[ilow+k] = ((ppi[k]*alphaTbl[k])>>15) +
60 ((ppo[k]*alphaTbl[interp_len-1-k])>>15);
61 for k = 0..interp_len-1
62 */
63 WebRtcSpl_ElementwiseVectorMult(&cbVec[ilow], ppi, WebRtcIlbcfix_kAlpha,
64 interp_len, 15);
65 WebRtcSpl_ReverseOrderMultArrayElements(
66 cbVecTmp, ppo, &WebRtcIlbcfix_kAlpha[interp_len - 1], interp_len, 15);
67 WebRtcSpl_AddVectorsAndShift(&cbVec[ilow], &cbVec[ilow], cbVecTmp, interp_len,
68 0);
69
70 /* copy the second noninterpolated part */
71 ppo = buffer - index;
72 /* `tempbuff2` is declared in WebRtcIlbcfix_GetCbVec and is SUBL+5 elements
73 long. `buffer` points one element past the end of that vector, i.e., at
74 tempbuff2+SUBL+5. Since ppo=buffer-index, we cannot read any more than
75 `index` elements from `ppo`.
76
77 `cbVec` is declared to be SUBL elements long in WebRtcIlbcfix_CbConstruct.
78 Therefore, we can only write SUBL-index elements to cbVec+index.
79
80 These two conditions limit the number of elements to copy.
81 */
82 WEBRTC_SPL_MEMCPY_W16(cbVec+index, ppo, WEBRTC_SPL_MIN(SUBL-index, index));
83 }
84