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_FrameClassify.c
16
17 ******************************************************************/
18
19 #include "modules/audio_coding/codecs/ilbc/defines.h"
20 #include "modules/audio_coding/codecs/ilbc/constants.h"
21
22 /*----------------------------------------------------------------*
23 * Classification of subframes to localize start state
24 *---------------------------------------------------------------*/
25
WebRtcIlbcfix_FrameClassify(IlbcEncoder * iLBCenc_inst,int16_t * residualFIX)26 size_t WebRtcIlbcfix_FrameClassify(
27 /* (o) Index to the max-energy sub frame */
28 IlbcEncoder *iLBCenc_inst,
29 /* (i/o) the encoder state structure */
30 int16_t *residualFIX /* (i) lpc residual signal */
31 ){
32 int16_t max, scale;
33 int32_t ssqEn[NSUB_MAX-1];
34 int16_t *ssqPtr;
35 int32_t *seqEnPtr;
36 int32_t maxW32;
37 int16_t scale1;
38 size_t pos;
39 size_t n;
40
41 /*
42 Calculate the energy of each of the 80 sample blocks
43 in the draft the 4 first and last samples are windowed with 1/5...4/5
44 and 4/5...1/5 respectively. To simplify for the fixpoint we have changed
45 this to 0 0 1 1 and 1 1 0 0
46 */
47
48 max = WebRtcSpl_MaxAbsValueW16(residualFIX, iLBCenc_inst->blockl);
49 scale = WebRtcSpl_GetSizeInBits((uint32_t)(max * max));
50
51 /* Scale to maximum 24 bits so that it won't overflow for 76 samples */
52 scale = scale-24;
53 scale1 = WEBRTC_SPL_MAX(0, scale);
54
55 /* Calculate energies */
56 ssqPtr=residualFIX + 2;
57 seqEnPtr=ssqEn;
58 for (n=(iLBCenc_inst->nsub-1); n>0; n--) {
59 (*seqEnPtr) = WebRtcSpl_DotProductWithScale(ssqPtr, ssqPtr, 76, scale1);
60 ssqPtr += 40;
61 seqEnPtr++;
62 }
63
64 /* Scale to maximum 20 bits in order to allow for the 11 bit window */
65 maxW32 = WebRtcSpl_MaxValueW32(ssqEn, iLBCenc_inst->nsub - 1);
66 scale = WebRtcSpl_GetSizeInBits(maxW32) - 20;
67 scale1 = WEBRTC_SPL_MAX(0, scale);
68
69 /* Window each 80 block with the ssqEn_winTbl window to give higher probability for
70 the blocks in the middle
71 */
72 seqEnPtr=ssqEn;
73 if (iLBCenc_inst->mode==20) {
74 ssqPtr=(int16_t*)WebRtcIlbcfix_kStartSequenceEnrgWin+1;
75 } else {
76 ssqPtr=(int16_t*)WebRtcIlbcfix_kStartSequenceEnrgWin;
77 }
78 for (n=(iLBCenc_inst->nsub-1); n>0; n--) {
79 (*seqEnPtr)=WEBRTC_SPL_MUL(((*seqEnPtr)>>scale1), (*ssqPtr));
80 seqEnPtr++;
81 ssqPtr++;
82 }
83
84 /* Extract the best choise of start state */
85 pos = WebRtcSpl_MaxIndexW32(ssqEn, iLBCenc_inst->nsub - 1) + 1;
86
87 return(pos);
88 }
89