1 /*
2  *  Copyright (c) 2012 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_Decode.c
16 
17 ******************************************************************/
18 
19 // Defines WEBRTC_ARCH_BIG_ENDIAN, used below.
20 #include "rtc_base/system/arch.h"
21 
22 #include "modules/audio_coding/codecs/ilbc/defines.h"
23 #include "modules/audio_coding/codecs/ilbc/simple_lsf_dequant.h"
24 #include "modules/audio_coding/codecs/ilbc/decoder_interpolate_lsf.h"
25 #include "modules/audio_coding/codecs/ilbc/index_conv_dec.h"
26 #include "modules/audio_coding/codecs/ilbc/do_plc.h"
27 #include "modules/audio_coding/codecs/ilbc/constants.h"
28 #include "modules/audio_coding/codecs/ilbc/enhancer_interface.h"
29 #include "modules/audio_coding/codecs/ilbc/xcorr_coef.h"
30 #include "modules/audio_coding/codecs/ilbc/lsf_check.h"
31 #include "modules/audio_coding/codecs/ilbc/decode_residual.h"
32 #include "modules/audio_coding/codecs/ilbc/unpack_bits.h"
33 #include "modules/audio_coding/codecs/ilbc/hp_output.h"
34 #include "modules/audio_coding/codecs/ilbc/init_decode.h"
35 #ifndef WEBRTC_ARCH_BIG_ENDIAN
36 #include "modules/audio_coding/codecs/ilbc/swap_bytes.h"
37 #endif
38 
39 /*----------------------------------------------------------------*
40  *  main decoder function
41  *---------------------------------------------------------------*/
42 
WebRtcIlbcfix_DecodeImpl(int16_t * decblock,const uint16_t * bytes,IlbcDecoder * iLBCdec_inst,int16_t mode)43 int WebRtcIlbcfix_DecodeImpl(
44     int16_t *decblock,    /* (o) decoded signal block */
45     const uint16_t *bytes, /* (i) encoded signal bits */
46     IlbcDecoder *iLBCdec_inst, /* (i/o) the decoder state
47                                            structure */
48     int16_t mode      /* (i) 0: bad packet, PLC,
49                                                                    1: normal */
50                            ) {
51   const int old_mode = iLBCdec_inst->mode;
52   const int old_use_enhancer = iLBCdec_inst->use_enhancer;
53 
54   size_t i;
55   int16_t order_plus_one;
56 
57   int16_t last_bit;
58   int16_t *data;
59   /* Stack based */
60   int16_t decresidual[BLOCKL_MAX];
61   int16_t PLCresidual[BLOCKL_MAX + LPC_FILTERORDER];
62   int16_t syntdenum[NSUB_MAX*(LPC_FILTERORDER+1)];
63   int16_t PLClpc[LPC_FILTERORDER + 1];
64 #ifndef WEBRTC_ARCH_BIG_ENDIAN
65   uint16_t swapped[NO_OF_WORDS_30MS];
66 #endif
67   iLBC_bits *iLBCbits_inst = (iLBC_bits*)PLCresidual;
68 
69   /* Reuse some buffers that are non overlapping in order to save stack memory */
70   data = &PLCresidual[LPC_FILTERORDER];
71 
72   if (mode) { /* the data are good */
73 
74     /* decode data */
75 
76     /* Unpacketize bits into parameters */
77 
78 #ifndef WEBRTC_ARCH_BIG_ENDIAN
79     WebRtcIlbcfix_SwapBytes(bytes, iLBCdec_inst->no_of_words, swapped);
80     last_bit = WebRtcIlbcfix_UnpackBits(swapped, iLBCbits_inst, iLBCdec_inst->mode);
81 #else
82     last_bit = WebRtcIlbcfix_UnpackBits(bytes, iLBCbits_inst, iLBCdec_inst->mode);
83 #endif
84 
85     /* Check for bit errors */
86     if (iLBCbits_inst->startIdx<1)
87       mode = 0;
88     if ((iLBCdec_inst->mode==20) && (iLBCbits_inst->startIdx>3))
89       mode = 0;
90     if ((iLBCdec_inst->mode==30) && (iLBCbits_inst->startIdx>5))
91       mode = 0;
92     if (last_bit==1)
93       mode = 0;
94 
95     if (mode) { /* No bit errors was detected, continue decoding */
96       /* Stack based */
97       int16_t lsfdeq[LPC_FILTERORDER*LPC_N_MAX];
98       int16_t weightdenum[(LPC_FILTERORDER + 1)*NSUB_MAX];
99 
100       /* adjust index */
101       WebRtcIlbcfix_IndexConvDec(iLBCbits_inst->cb_index);
102 
103       /* decode the lsf */
104       WebRtcIlbcfix_SimpleLsfDeQ(lsfdeq, (int16_t*)(iLBCbits_inst->lsf), iLBCdec_inst->lpc_n);
105       WebRtcIlbcfix_LsfCheck(lsfdeq, LPC_FILTERORDER, iLBCdec_inst->lpc_n);
106       WebRtcIlbcfix_DecoderInterpolateLsp(syntdenum, weightdenum,
107                                           lsfdeq, LPC_FILTERORDER, iLBCdec_inst);
108 
109       /* Decode the residual using the cb and gain indexes */
110       if (!WebRtcIlbcfix_DecodeResidual(iLBCdec_inst, iLBCbits_inst,
111                                         decresidual, syntdenum))
112         goto error;
113 
114       /* preparing the plc for a future loss! */
115       WebRtcIlbcfix_DoThePlc(
116           PLCresidual, PLClpc, 0, decresidual,
117           syntdenum + (LPC_FILTERORDER + 1) * (iLBCdec_inst->nsub - 1),
118           iLBCdec_inst->last_lag, iLBCdec_inst);
119 
120       /* Use the output from doThePLC */
121       WEBRTC_SPL_MEMCPY_W16(decresidual, PLCresidual, iLBCdec_inst->blockl);
122     }
123 
124   }
125 
126   if (mode == 0) {
127     /* the data is bad (either a PLC call
128      * was made or a bit error was detected)
129      */
130 
131     /* packet loss conceal */
132 
133     WebRtcIlbcfix_DoThePlc(PLCresidual, PLClpc, 1, decresidual, syntdenum,
134                            iLBCdec_inst->last_lag, iLBCdec_inst);
135 
136     WEBRTC_SPL_MEMCPY_W16(decresidual, PLCresidual, iLBCdec_inst->blockl);
137 
138     order_plus_one = LPC_FILTERORDER + 1;
139 
140     for (i = 0; i < iLBCdec_inst->nsub; i++) {
141       WEBRTC_SPL_MEMCPY_W16(syntdenum+(i*order_plus_one),
142                             PLClpc, order_plus_one);
143     }
144   }
145 
146   if ((*iLBCdec_inst).use_enhancer == 1) { /* Enhancer activated */
147 
148     /* Update the filter and filter coefficients if there was a packet loss */
149     if (iLBCdec_inst->prev_enh_pl==2) {
150       for (i=0;i<iLBCdec_inst->nsub;i++) {
151         WEBRTC_SPL_MEMCPY_W16(&(iLBCdec_inst->old_syntdenum[i*(LPC_FILTERORDER+1)]),
152                               syntdenum, (LPC_FILTERORDER+1));
153       }
154     }
155 
156     /* post filtering */
157     (*iLBCdec_inst).last_lag =
158         WebRtcIlbcfix_EnhancerInterface(data, decresidual, iLBCdec_inst);
159 
160     /* synthesis filtering */
161 
162     /* Set up the filter state */
163     WEBRTC_SPL_MEMCPY_W16(&data[-LPC_FILTERORDER], iLBCdec_inst->syntMem, LPC_FILTERORDER);
164 
165     if (iLBCdec_inst->mode==20) {
166       /* Enhancer has 40 samples delay */
167       i=0;
168       WebRtcSpl_FilterARFastQ12(
169           data, data,
170           iLBCdec_inst->old_syntdenum + (i+iLBCdec_inst->nsub-1)*(LPC_FILTERORDER+1),
171           LPC_FILTERORDER+1, SUBL);
172 
173       for (i=1; i < iLBCdec_inst->nsub; i++) {
174         WebRtcSpl_FilterARFastQ12(
175             data+i*SUBL, data+i*SUBL,
176             syntdenum+(i-1)*(LPC_FILTERORDER+1),
177             LPC_FILTERORDER+1, SUBL);
178       }
179 
180     } else if (iLBCdec_inst->mode==30) {
181       /* Enhancer has 80 samples delay */
182       for (i=0; i < 2; i++) {
183         WebRtcSpl_FilterARFastQ12(
184             data+i*SUBL, data+i*SUBL,
185             iLBCdec_inst->old_syntdenum + (i+4)*(LPC_FILTERORDER+1),
186             LPC_FILTERORDER+1, SUBL);
187       }
188       for (i=2; i < iLBCdec_inst->nsub; i++) {
189         WebRtcSpl_FilterARFastQ12(
190             data+i*SUBL, data+i*SUBL,
191             syntdenum+(i-2)*(LPC_FILTERORDER+1),
192             LPC_FILTERORDER+1, SUBL);
193       }
194     }
195 
196     /* Save the filter state */
197     WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->syntMem, &data[iLBCdec_inst->blockl-LPC_FILTERORDER], LPC_FILTERORDER);
198 
199   } else { /* Enhancer not activated */
200     size_t lag;
201 
202     /* Find last lag (since the enhancer is not called to give this info) */
203     lag = 20;
204     if (iLBCdec_inst->mode==20) {
205       lag = WebRtcIlbcfix_XcorrCoef(
206           &decresidual[iLBCdec_inst->blockl-60],
207           &decresidual[iLBCdec_inst->blockl-60-lag],
208           60,
209           80, lag, -1);
210     } else {
211       lag = WebRtcIlbcfix_XcorrCoef(
212           &decresidual[iLBCdec_inst->blockl-ENH_BLOCKL],
213           &decresidual[iLBCdec_inst->blockl-ENH_BLOCKL-lag],
214           ENH_BLOCKL,
215           100, lag, -1);
216     }
217 
218     /* Store lag (it is needed if next packet is lost) */
219     (*iLBCdec_inst).last_lag = lag;
220 
221     /* copy data and run synthesis filter */
222     WEBRTC_SPL_MEMCPY_W16(data, decresidual, iLBCdec_inst->blockl);
223 
224     /* Set up the filter state */
225     WEBRTC_SPL_MEMCPY_W16(&data[-LPC_FILTERORDER], iLBCdec_inst->syntMem, LPC_FILTERORDER);
226 
227     for (i=0; i < iLBCdec_inst->nsub; i++) {
228       WebRtcSpl_FilterARFastQ12(
229           data+i*SUBL, data+i*SUBL,
230           syntdenum + i*(LPC_FILTERORDER+1),
231           LPC_FILTERORDER+1, SUBL);
232     }
233 
234     /* Save the filter state */
235     WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->syntMem, &data[iLBCdec_inst->blockl-LPC_FILTERORDER], LPC_FILTERORDER);
236   }
237 
238   WEBRTC_SPL_MEMCPY_W16(decblock,data,iLBCdec_inst->blockl);
239 
240   /* High pass filter the signal (with upscaling a factor 2 and saturation) */
241   WebRtcIlbcfix_HpOutput(decblock, (int16_t*)WebRtcIlbcfix_kHpOutCoefs,
242                          iLBCdec_inst->hpimemy, iLBCdec_inst->hpimemx,
243                          iLBCdec_inst->blockl);
244 
245   WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->old_syntdenum,
246                         syntdenum, iLBCdec_inst->nsub*(LPC_FILTERORDER+1));
247 
248   iLBCdec_inst->prev_enh_pl=0;
249 
250   if (mode==0) { /* PLC was used */
251     iLBCdec_inst->prev_enh_pl=1;
252   }
253 
254   return 0;  // Success.
255 
256 error:
257   // The decoder got sick from eating that data. Reset it and return.
258   WebRtcIlbcfix_InitDecode(iLBCdec_inst, old_mode, old_use_enhancer);
259   return -1;  // Error
260 }
261