Clean up: alignment of comments
[opus.git] / silk / control_codec.c
1 /***********************************************************************
2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3 Redistribution and use in source and binary forms, with or without
4 modification, are permitted provided that the following conditions
5 are met:
6 - Redistributions of source code must retain the above copyright notice,
7 this list of conditions and the following disclaimer.
8 - Redistributions in binary form must reproduce the above copyright
9 notice, this list of conditions and the following disclaimer in the
10 documentation and/or other materials provided with the distribution.
11 - Neither the name of Internet Society, IETF or IETF Trust, nor the
12 names of specific contributors, may be used to endorse or promote
13 products derived from this software without specific prior written
14 permission.
15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 POSSIBILITY OF SUCH DAMAGE.
26 ***********************************************************************/
27
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31 #ifdef FIXED_POINT
32 #include "main_FIX.h"
33 #define silk_encoder_state_Fxx      silk_encoder_state_FIX
34 #else
35 #include "main_FLP.h"
36 #define silk_encoder_state_Fxx      silk_encoder_state_FLP
37 #endif
38 #include "stack_alloc.h"
39 #include "tuning_parameters.h"
40 #include "pitch_est_defines.h"
41
42 static opus_int silk_setup_resamplers(
43     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
44     opus_int                        fs_kHz              /* I                        */
45 );
46
47 static opus_int silk_setup_fs(
48     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
49     opus_int                        fs_kHz,             /* I                        */
50     opus_int                        PacketSize_ms       /* I                        */
51 );
52
53 static opus_int silk_setup_complexity(
54     silk_encoder_state              *psEncC,            /* I/O                      */
55     opus_int                        Complexity          /* I                        */
56 );
57
58 static OPUS_INLINE opus_int silk_setup_LBRR(
59     silk_encoder_state              *psEncC,            /* I/O                      */
60     const opus_int32                TargetRate_bps      /* I                        */
61 );
62
63
64 /* Control encoder */
65 opus_int silk_control_encoder(
66     silk_encoder_state_Fxx          *psEnc,                                 /* I/O  Pointer to Silk encoder state                                               */
67     silk_EncControlStruct           *encControl,                            /* I    Control structure                                                           */
68     const opus_int32                TargetRate_bps,                         /* I    Target max bitrate (bps)                                                    */
69     const opus_int                  allow_bw_switch,                        /* I    Flag to allow switching audio bandwidth                                     */
70     const opus_int                  channelNb,                              /* I    Channel number                                                              */
71     const opus_int                  force_fs_kHz
72 )
73 {
74     opus_int   fs_kHz, ret = 0;
75
76     psEnc->sCmn.useDTX                 = encControl->useDTX;
77     psEnc->sCmn.useCBR                 = encControl->useCBR;
78     psEnc->sCmn.API_fs_Hz              = encControl->API_sampleRate;
79     psEnc->sCmn.maxInternal_fs_Hz      = encControl->maxInternalSampleRate;
80     psEnc->sCmn.minInternal_fs_Hz      = encControl->minInternalSampleRate;
81     psEnc->sCmn.desiredInternal_fs_Hz  = encControl->desiredInternalSampleRate;
82     psEnc->sCmn.useInBandFEC           = encControl->useInBandFEC;
83     psEnc->sCmn.nChannelsAPI           = encControl->nChannelsAPI;
84     psEnc->sCmn.nChannelsInternal      = encControl->nChannelsInternal;
85     psEnc->sCmn.allow_bandwidth_switch = allow_bw_switch;
86     psEnc->sCmn.channelNb              = channelNb;
87
88     if( psEnc->sCmn.controlled_since_last_payload != 0 && psEnc->sCmn.prefillFlag == 0 ) {
89         if( psEnc->sCmn.API_fs_Hz != psEnc->sCmn.prev_API_fs_Hz && psEnc->sCmn.fs_kHz > 0 ) {
90             /* Change in API sampling rate in the middle of encoding a packet */
91             ret += silk_setup_resamplers( psEnc, psEnc->sCmn.fs_kHz );
92         }
93         return ret;
94     }
95
96     /* Beyond this point we know that there are no previously coded frames in the payload buffer */
97
98     /********************************************/
99     /* Determine internal sampling rate         */
100     /********************************************/
101     fs_kHz = silk_control_audio_bandwidth( &psEnc->sCmn, encControl );
102     if( force_fs_kHz ) {
103        fs_kHz = force_fs_kHz;
104     }
105     /********************************************/
106     /* Prepare resampler and buffered data      */
107     /********************************************/
108     ret += silk_setup_resamplers( psEnc, fs_kHz );
109
110     /********************************************/
111     /* Set internal sampling frequency          */
112     /********************************************/
113     ret += silk_setup_fs( psEnc, fs_kHz, encControl->payloadSize_ms );
114
115     /********************************************/
116     /* Set encoding complexity                  */
117     /********************************************/
118     ret += silk_setup_complexity( &psEnc->sCmn, encControl->complexity  );
119
120     /********************************************/
121     /* Set packet loss rate measured by farend  */
122     /********************************************/
123     psEnc->sCmn.PacketLoss_perc = encControl->packetLossPercentage;
124
125     /********************************************/
126     /* Set LBRR usage                           */
127     /********************************************/
128     ret += silk_setup_LBRR( &psEnc->sCmn, TargetRate_bps );
129
130     psEnc->sCmn.controlled_since_last_payload = 1;
131
132     return ret;
133 }
134
135 static opus_int silk_setup_resamplers(
136     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
137     opus_int                         fs_kHz              /* I                        */
138 )
139 {
140     opus_int   ret = SILK_NO_ERROR;
141     SAVE_STACK;
142
143     if( psEnc->sCmn.fs_kHz != fs_kHz || psEnc->sCmn.prev_API_fs_Hz != psEnc->sCmn.API_fs_Hz )
144     {
145         if( psEnc->sCmn.fs_kHz == 0 ) {
146             /* Initialize the resampler for enc_API.c preparing resampling from API_fs_Hz to fs_kHz */
147             ret += silk_resampler_init( &psEnc->sCmn.resampler_state, psEnc->sCmn.API_fs_Hz, fs_kHz * 1000, 1 );
148         } else {
149             VARDECL( opus_int16, x_buf_API_fs_Hz );
150             VARDECL( silk_resampler_state_struct, temp_resampler_state );
151 #ifdef FIXED_POINT
152             opus_int16 *x_bufFIX = psEnc->x_buf;
153 #else
154             VARDECL( opus_int16, x_bufFIX );
155             opus_int32 new_buf_samples;
156 #endif
157             opus_int32 api_buf_samples;
158             opus_int32 old_buf_samples;
159             opus_int32 buf_length_ms;
160
161             buf_length_ms = silk_LSHIFT( psEnc->sCmn.nb_subfr * 5, 1 ) + LA_SHAPE_MS;
162             old_buf_samples = buf_length_ms * psEnc->sCmn.fs_kHz;
163
164 #ifndef FIXED_POINT
165             new_buf_samples = buf_length_ms * fs_kHz;
166             ALLOC( x_bufFIX, silk_max( old_buf_samples, new_buf_samples ),
167                    opus_int16 );
168             silk_float2short_array( x_bufFIX, psEnc->x_buf, old_buf_samples );
169 #endif
170
171             /* Initialize resampler for temporary resampling of x_buf data to API_fs_Hz */
172             ALLOC( temp_resampler_state, 1, silk_resampler_state_struct );
173             ret += silk_resampler_init( temp_resampler_state, silk_SMULBB( psEnc->sCmn.fs_kHz, 1000 ), psEnc->sCmn.API_fs_Hz, 0 );
174
175             /* Calculate number of samples to temporarily upsample */
176             api_buf_samples = buf_length_ms * silk_DIV32_16( psEnc->sCmn.API_fs_Hz, 1000 );
177
178             /* Temporary resampling of x_buf data to API_fs_Hz */
179             ALLOC( x_buf_API_fs_Hz, api_buf_samples, opus_int16 );
180             ret += silk_resampler( temp_resampler_state, x_buf_API_fs_Hz, x_bufFIX, old_buf_samples );
181
182             /* Initialize the resampler for enc_API.c preparing resampling from API_fs_Hz to fs_kHz */
183             ret += silk_resampler_init( &psEnc->sCmn.resampler_state, psEnc->sCmn.API_fs_Hz, silk_SMULBB( fs_kHz, 1000 ), 1 );
184
185             /* Correct resampler state by resampling buffered data from API_fs_Hz to fs_kHz */
186             ret += silk_resampler( &psEnc->sCmn.resampler_state, x_bufFIX, x_buf_API_fs_Hz, api_buf_samples );
187
188 #ifndef FIXED_POINT
189             silk_short2float_array( psEnc->x_buf, x_bufFIX, new_buf_samples);
190 #endif
191         }
192     }
193
194     psEnc->sCmn.prev_API_fs_Hz = psEnc->sCmn.API_fs_Hz;
195
196     RESTORE_STACK;
197     return ret;
198 }
199
200 static opus_int silk_setup_fs(
201     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
202     opus_int                        fs_kHz,             /* I                        */
203     opus_int                        PacketSize_ms       /* I                        */
204 )
205 {
206     opus_int ret = SILK_NO_ERROR;
207
208     /* Set packet size */
209     if( PacketSize_ms != psEnc->sCmn.PacketSize_ms ) {
210         if( ( PacketSize_ms !=  10 ) &&
211             ( PacketSize_ms !=  20 ) &&
212             ( PacketSize_ms !=  40 ) &&
213             ( PacketSize_ms !=  60 ) ) {
214             ret = SILK_ENC_PACKET_SIZE_NOT_SUPPORTED;
215         }
216         if( PacketSize_ms <= 10 ) {
217             psEnc->sCmn.nFramesPerPacket = 1;
218             psEnc->sCmn.nb_subfr = PacketSize_ms == 10 ? 2 : 1;
219             psEnc->sCmn.frame_length = silk_SMULBB( PacketSize_ms, fs_kHz );
220             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS_2_SF, fs_kHz );
221             if( psEnc->sCmn.fs_kHz == 8 ) {
222                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_NB_iCDF;
223             } else {
224                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_iCDF;
225             }
226         } else {
227             psEnc->sCmn.nFramesPerPacket = silk_DIV32_16( PacketSize_ms, MAX_FRAME_LENGTH_MS );
228             psEnc->sCmn.nb_subfr = MAX_NB_SUBFR;
229             psEnc->sCmn.frame_length = silk_SMULBB( 20, fs_kHz );
230             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS, fs_kHz );
231             if( psEnc->sCmn.fs_kHz == 8 ) {
232                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_NB_iCDF;
233             } else {
234                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_iCDF;
235             }
236         }
237         psEnc->sCmn.PacketSize_ms  = PacketSize_ms;
238         psEnc->sCmn.TargetRate_bps = 0;         /* trigger new SNR computation */
239     }
240
241     /* Set internal sampling frequency */
242     silk_assert( fs_kHz == 8 || fs_kHz == 12 || fs_kHz == 16 );
243     silk_assert( psEnc->sCmn.nb_subfr == 2 || psEnc->sCmn.nb_subfr == 4 );
244     if( psEnc->sCmn.fs_kHz != fs_kHz ) {
245         /* reset part of the state */
246         silk_memset( &psEnc->sShape,               0, sizeof( psEnc->sShape ) );
247         silk_memset( &psEnc->sCmn.sNSQ,            0, sizeof( psEnc->sCmn.sNSQ ) );
248         silk_memset( psEnc->sCmn.prev_NLSFq_Q15,   0, sizeof( psEnc->sCmn.prev_NLSFq_Q15 ) );
249         silk_memset( &psEnc->sCmn.sLP.In_LP_State, 0, sizeof( psEnc->sCmn.sLP.In_LP_State ) );
250         psEnc->sCmn.inputBufIx                  = 0;
251         psEnc->sCmn.nFramesEncoded              = 0;
252         psEnc->sCmn.TargetRate_bps              = 0;     /* trigger new SNR computation */
253
254         /* Initialize non-zero parameters */
255         psEnc->sCmn.prevLag                     = 100;
256         psEnc->sCmn.first_frame_after_reset     = 1;
257         psEnc->sShape.LastGainIndex             = 10;
258         psEnc->sCmn.sNSQ.lagPrev                = 100;
259         psEnc->sCmn.sNSQ.prev_gain_Q16          = 65536;
260         psEnc->sCmn.prevSignalType              = TYPE_NO_VOICE_ACTIVITY;
261
262         psEnc->sCmn.fs_kHz = fs_kHz;
263         if( psEnc->sCmn.fs_kHz == 8 ) {
264             if( psEnc->sCmn.nb_subfr == MAX_NB_SUBFR ) {
265                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_NB_iCDF;
266             } else {
267                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_NB_iCDF;
268             }
269         } else {
270             if( psEnc->sCmn.nb_subfr == MAX_NB_SUBFR ) {
271                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_iCDF;
272             } else {
273                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_iCDF;
274             }
275         }
276         if( psEnc->sCmn.fs_kHz == 8 || psEnc->sCmn.fs_kHz == 12 ) {
277             psEnc->sCmn.predictLPCOrder = MIN_LPC_ORDER;
278             psEnc->sCmn.psNLSF_CB  = &silk_NLSF_CB_NB_MB;
279         } else {
280             psEnc->sCmn.predictLPCOrder = MAX_LPC_ORDER;
281             psEnc->sCmn.psNLSF_CB  = &silk_NLSF_CB_WB;
282         }
283         psEnc->sCmn.subfr_length   = SUB_FRAME_LENGTH_MS * fs_kHz;
284         psEnc->sCmn.frame_length   = silk_SMULBB( psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr );
285         psEnc->sCmn.ltp_mem_length = silk_SMULBB( LTP_MEM_LENGTH_MS, fs_kHz );
286         psEnc->sCmn.la_pitch       = silk_SMULBB( LA_PITCH_MS, fs_kHz );
287         psEnc->sCmn.max_pitch_lag  = silk_SMULBB( 18, fs_kHz );
288         if( psEnc->sCmn.nb_subfr == MAX_NB_SUBFR ) {
289             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS, fs_kHz );
290         } else {
291             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS_2_SF, fs_kHz );
292         }
293         if( psEnc->sCmn.fs_kHz == 16 ) {
294             psEnc->sCmn.pitch_lag_low_bits_iCDF = silk_uniform8_iCDF;
295         } else if( psEnc->sCmn.fs_kHz == 12 ) {
296             psEnc->sCmn.pitch_lag_low_bits_iCDF = silk_uniform6_iCDF;
297         } else {
298             psEnc->sCmn.pitch_lag_low_bits_iCDF = silk_uniform4_iCDF;
299         }
300     }
301
302     /* Check that settings are valid */
303     silk_assert( ( psEnc->sCmn.subfr_length * psEnc->sCmn.nb_subfr ) == psEnc->sCmn.frame_length );
304
305     return ret;
306 }
307
308 static opus_int silk_setup_complexity(
309     silk_encoder_state              *psEncC,            /* I/O                      */
310     opus_int                        Complexity          /* I                        */
311 )
312 {
313     opus_int ret = 0;
314
315     /* Set encoding complexity */
316     silk_assert( Complexity >= 0 && Complexity <= 10 );
317     if( Complexity < 1 ) {
318         psEncC->pitchEstimationComplexity       = SILK_PE_MIN_COMPLEX;
319         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.8, 16 );
320         psEncC->pitchEstimationLPCOrder         = 6;
321         psEncC->shapingLPCOrder                 = 8;
322         psEncC->la_shape                        = 3 * psEncC->fs_kHz;
323         psEncC->nStatesDelayedDecision          = 1;
324         psEncC->useInterpolatedNLSFs            = 0;
325         psEncC->NLSF_MSVQ_Survivors             = 2;
326         psEncC->warping_Q16                     = 0;
327     } else if( Complexity < 2 ) {
328         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
329         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.76, 16 );
330         psEncC->pitchEstimationLPCOrder         = 8;
331         psEncC->shapingLPCOrder                 = 10;
332         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
333         psEncC->nStatesDelayedDecision          = 1;
334         psEncC->useInterpolatedNLSFs            = 0;
335         psEncC->NLSF_MSVQ_Survivors             = 3;
336         psEncC->warping_Q16                     = 0;
337     } else if( Complexity < 3 ) {
338         psEncC->pitchEstimationComplexity       = SILK_PE_MIN_COMPLEX;
339         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.8, 16 );
340         psEncC->pitchEstimationLPCOrder         = 6;
341         psEncC->shapingLPCOrder                 = 8;
342         psEncC->la_shape                        = 3 * psEncC->fs_kHz;
343         psEncC->nStatesDelayedDecision          = 2;
344         psEncC->useInterpolatedNLSFs            = 0;
345         psEncC->NLSF_MSVQ_Survivors             = 2;
346         psEncC->warping_Q16                     = 0;
347     } else if( Complexity < 4 ) {
348         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
349         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.76, 16 );
350         psEncC->pitchEstimationLPCOrder         = 8;
351         psEncC->shapingLPCOrder                 = 10;
352         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
353         psEncC->nStatesDelayedDecision          = 2;
354         psEncC->useInterpolatedNLSFs            = 0;
355         psEncC->NLSF_MSVQ_Survivors             = 4;
356         psEncC->warping_Q16                     = 0;
357     } else if( Complexity < 6 ) {
358         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
359         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.74, 16 );
360         psEncC->pitchEstimationLPCOrder         = 10;
361         psEncC->shapingLPCOrder                 = 12;
362         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
363         psEncC->nStatesDelayedDecision          = 2;
364         psEncC->useInterpolatedNLSFs            = 1;
365         psEncC->NLSF_MSVQ_Survivors             = 6;
366         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
367     } else if( Complexity < 8 ) {
368         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
369         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.72, 16 );
370         psEncC->pitchEstimationLPCOrder         = 12;
371         psEncC->shapingLPCOrder                 = 14;
372         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
373         psEncC->nStatesDelayedDecision          = 3;
374         psEncC->useInterpolatedNLSFs            = 1;
375         psEncC->NLSF_MSVQ_Survivors             = 8;
376         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
377     } else {
378         psEncC->pitchEstimationComplexity       = SILK_PE_MAX_COMPLEX;
379         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.7, 16 );
380         psEncC->pitchEstimationLPCOrder         = 16;
381         psEncC->shapingLPCOrder                 = 16;
382         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
383         psEncC->nStatesDelayedDecision          = MAX_DEL_DEC_STATES;
384         psEncC->useInterpolatedNLSFs            = 1;
385         psEncC->NLSF_MSVQ_Survivors             = 16;
386         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
387     }
388
389     /* Do not allow higher pitch estimation LPC order than predict LPC order */
390     psEncC->pitchEstimationLPCOrder = silk_min_int( psEncC->pitchEstimationLPCOrder, psEncC->predictLPCOrder );
391     psEncC->shapeWinLength          = SUB_FRAME_LENGTH_MS * psEncC->fs_kHz + 2 * psEncC->la_shape;
392     psEncC->Complexity              = Complexity;
393
394     silk_assert( psEncC->pitchEstimationLPCOrder <= MAX_FIND_PITCH_LPC_ORDER );
395     silk_assert( psEncC->shapingLPCOrder         <= MAX_SHAPE_LPC_ORDER      );
396     silk_assert( psEncC->nStatesDelayedDecision  <= MAX_DEL_DEC_STATES       );
397     silk_assert( psEncC->warping_Q16             <= 32767                    );
398     silk_assert( psEncC->la_shape                <= LA_SHAPE_MAX             );
399     silk_assert( psEncC->shapeWinLength          <= SHAPE_LPC_WIN_MAX        );
400
401     return ret;
402 }
403
404 static OPUS_INLINE opus_int silk_setup_LBRR(
405     silk_encoder_state          *psEncC,            /* I/O                      */
406     const opus_int32            TargetRate_bps      /* I                        */
407 )
408 {
409     opus_int   LBRR_in_previous_packet, ret = SILK_NO_ERROR;
410     opus_int32 LBRR_rate_thres_bps;
411
412     LBRR_in_previous_packet = psEncC->LBRR_enabled;
413     psEncC->LBRR_enabled = 0;
414     if( psEncC->useInBandFEC && psEncC->PacketLoss_perc > 0 ) {
415         if( psEncC->fs_kHz == 8 ) {
416             LBRR_rate_thres_bps = LBRR_NB_MIN_RATE_BPS;
417         } else if( psEncC->fs_kHz == 12 ) {
418             LBRR_rate_thres_bps = LBRR_MB_MIN_RATE_BPS;
419         } else {
420             LBRR_rate_thres_bps = LBRR_WB_MIN_RATE_BPS;
421         }
422         LBRR_rate_thres_bps = silk_SMULWB( silk_MUL( LBRR_rate_thres_bps, 125 - silk_min( psEncC->PacketLoss_perc, 25 ) ), SILK_FIX_CONST( 0.01, 16 ) );
423
424         if( TargetRate_bps > LBRR_rate_thres_bps ) {
425             /* Set gain increase for coding LBRR excitation */
426             if( LBRR_in_previous_packet == 0 ) {
427                 /* Previous packet did not have LBRR, and was therefore coded at a higher bitrate */
428                 psEncC->LBRR_GainIncreases = 7;
429             } else {
430                 psEncC->LBRR_GainIncreases = silk_max_int( 7 - silk_SMULWB( (opus_int32)psEncC->PacketLoss_perc, SILK_FIX_CONST( 0.4, 16 ) ), 2 );
431             }
432             psEncC->LBRR_enabled = 1;
433         }
434     }
435
436     return ret;
437 }