Mark functions static if they are only used in their own translation unit.
[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 "tuning_parameters.h"
39 #include "pitch_est_defines.h"
40
41 static opus_int silk_setup_resamplers(
42     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
43     opus_int                        fs_kHz              /* I                        */
44 );
45
46 static opus_int silk_setup_fs(
47     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
48     opus_int                        fs_kHz,             /* I                        */
49     opus_int                        PacketSize_ms       /* I                        */
50 );
51
52 static opus_int silk_setup_complexity(
53     silk_encoder_state              *psEncC,            /* I/O                      */
54     opus_int                        Complexity          /* I                        */
55 );
56
57 static inline opus_int silk_setup_LBRR(
58     silk_encoder_state              *psEncC,            /* I/O                      */
59     const opus_int32                TargetRate_bps      /* I                        */
60 );
61
62
63 /* Control encoder */
64 opus_int silk_control_encoder(
65     silk_encoder_state_Fxx          *psEnc,                                 /* I/O  Pointer to Silk encoder state                                               */
66     silk_EncControlStruct           *encControl,                            /* I    Control structure                                                           */
67     const opus_int32                TargetRate_bps,                         /* I    Target max bitrate (bps)                                                    */
68     const opus_int                  allow_bw_switch,                        /* I    Flag to allow switching audio bandwidth                                     */
69     const opus_int                  channelNb,                              /* I    Channel number                                                              */
70     const opus_int                  force_fs_kHz
71 )
72 {
73     opus_int   fs_kHz, ret = 0;
74
75     psEnc->sCmn.useDTX                 = encControl->useDTX;
76     psEnc->sCmn.useCBR                 = encControl->useCBR;
77     psEnc->sCmn.API_fs_Hz              = encControl->API_sampleRate;
78     psEnc->sCmn.maxInternal_fs_Hz      = encControl->maxInternalSampleRate;
79     psEnc->sCmn.minInternal_fs_Hz      = encControl->minInternalSampleRate;
80     psEnc->sCmn.desiredInternal_fs_Hz  = encControl->desiredInternalSampleRate;
81     psEnc->sCmn.useInBandFEC           = encControl->useInBandFEC;
82     psEnc->sCmn.nChannelsAPI           = encControl->nChannelsAPI;
83     psEnc->sCmn.nChannelsInternal      = encControl->nChannelsInternal;
84     psEnc->sCmn.allow_bandwidth_switch = allow_bw_switch;
85     psEnc->sCmn.channelNb              = channelNb;
86
87     if( psEnc->sCmn.controlled_since_last_payload != 0 && psEnc->sCmn.prefillFlag == 0 ) {
88         if( psEnc->sCmn.API_fs_Hz != psEnc->sCmn.prev_API_fs_Hz && psEnc->sCmn.fs_kHz > 0 ) {
89             /* Change in API sampling rate in the middle of encoding a packet */
90             ret += silk_setup_resamplers( psEnc, psEnc->sCmn.fs_kHz );
91         }
92         return ret;
93     }
94
95     /* Beyond this point we know that there are no previously coded frames in the payload buffer */
96
97     /********************************************/
98     /* Determine internal sampling rate         */
99     /********************************************/
100     fs_kHz = silk_control_audio_bandwidth( &psEnc->sCmn, encControl );
101     if( force_fs_kHz ) {
102        fs_kHz = force_fs_kHz;
103     }
104     /********************************************/
105     /* Prepare resampler and buffered data      */
106     /********************************************/
107     ret += silk_setup_resamplers( psEnc, fs_kHz );
108
109     /********************************************/
110     /* Set internal sampling frequency          */
111     /********************************************/
112     ret += silk_setup_fs( psEnc, fs_kHz, encControl->payloadSize_ms );
113
114     /********************************************/
115     /* Set encoding complexity                  */
116     /********************************************/
117     ret += silk_setup_complexity( &psEnc->sCmn, encControl->complexity  );
118
119     /********************************************/
120     /* Set packet loss rate measured by farend  */
121     /********************************************/
122     psEnc->sCmn.PacketLoss_perc = encControl->packetLossPercentage;
123
124     /********************************************/
125     /* Set LBRR usage                           */
126     /********************************************/
127     ret += silk_setup_LBRR( &psEnc->sCmn, TargetRate_bps );
128
129     psEnc->sCmn.controlled_since_last_payload = 1;
130
131     return ret;
132 }
133
134 static opus_int silk_setup_resamplers(
135     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
136     opus_int                         fs_kHz              /* I                        */
137 )
138 {
139     opus_int   ret = SILK_NO_ERROR;
140     opus_int32 nSamples_temp;
141
142     if( psEnc->sCmn.fs_kHz != fs_kHz || psEnc->sCmn.prev_API_fs_Hz != psEnc->sCmn.API_fs_Hz )
143     {
144         if( psEnc->sCmn.fs_kHz == 0 ) {
145             /* Initialize the resampler for enc_API.c preparing resampling from API_fs_Hz to fs_kHz */
146             ret += silk_resampler_init( &psEnc->sCmn.resampler_state, psEnc->sCmn.API_fs_Hz, fs_kHz * 1000, 1 );
147         } else {
148             /* Allocate worst case space for temporary upsampling, 8 to 48 kHz, so a factor 6 */
149             opus_int16 x_buf_API_fs_Hz[ ( 2 * MAX_FRAME_LENGTH_MS + LA_SHAPE_MS ) * MAX_API_FS_KHZ ];
150             silk_resampler_state_struct  temp_resampler_state;
151 #ifdef FIXED_POINT
152             opus_int16 *x_bufFIX = psEnc->x_buf;
153 #else
154             opus_int16 x_bufFIX[ 2 * MAX_FRAME_LENGTH + LA_SHAPE_MAX ];
155 #endif
156
157             nSamples_temp = silk_LSHIFT( psEnc->sCmn.frame_length, 1 ) + LA_SHAPE_MS * psEnc->sCmn.fs_kHz;
158
159 #ifndef FIXED_POINT
160             silk_float2short_array( x_bufFIX, psEnc->x_buf, nSamples_temp );
161 #endif
162
163             /* Initialize resampler for temporary resampling of x_buf data to API_fs_Hz */
164             ret += silk_resampler_init( &temp_resampler_state, silk_SMULBB( psEnc->sCmn.fs_kHz, 1000 ), psEnc->sCmn.API_fs_Hz, 0 );
165
166             /* Temporary resampling of x_buf data to API_fs_Hz */
167             ret += silk_resampler( &temp_resampler_state, x_buf_API_fs_Hz, x_bufFIX, nSamples_temp );
168
169             /* Calculate number of samples that has been temporarily upsampled */
170             nSamples_temp = silk_DIV32_16( nSamples_temp * psEnc->sCmn.API_fs_Hz, silk_SMULBB( psEnc->sCmn.fs_kHz, 1000 ) );
171
172             /* Initialize the resampler for enc_API.c preparing resampling from API_fs_Hz to fs_kHz */
173             ret += silk_resampler_init( &psEnc->sCmn.resampler_state, psEnc->sCmn.API_fs_Hz, silk_SMULBB( fs_kHz, 1000 ), 1 );
174
175             /* Correct resampler state by resampling buffered data from API_fs_Hz to fs_kHz */
176             ret += silk_resampler( &psEnc->sCmn.resampler_state, x_bufFIX, x_buf_API_fs_Hz, nSamples_temp );
177
178 #ifndef FIXED_POINT
179             silk_short2float_array( psEnc->x_buf, x_bufFIX, ( 2 * MAX_FRAME_LENGTH_MS + LA_SHAPE_MS ) * fs_kHz );
180 #endif
181         }
182     }
183
184     psEnc->sCmn.prev_API_fs_Hz = psEnc->sCmn.API_fs_Hz;
185
186     return ret;
187 }
188
189 static opus_int silk_setup_fs(
190     silk_encoder_state_Fxx          *psEnc,             /* I/O                      */
191     opus_int                        fs_kHz,             /* I                        */
192     opus_int                        PacketSize_ms       /* I                        */
193 )
194 {
195     opus_int ret = SILK_NO_ERROR;
196
197     /* Set packet size */
198     if( PacketSize_ms != psEnc->sCmn.PacketSize_ms ) {
199         if( ( PacketSize_ms !=  10 ) &&
200             ( PacketSize_ms !=  20 ) &&
201             ( PacketSize_ms !=  40 ) &&
202             ( PacketSize_ms !=  60 ) ) {
203             ret = SILK_ENC_PACKET_SIZE_NOT_SUPPORTED;
204         }
205         if( PacketSize_ms <= 10 ) {
206             psEnc->sCmn.nFramesPerPacket = 1;
207             psEnc->sCmn.nb_subfr = PacketSize_ms == 10 ? 2 : 1;
208             psEnc->sCmn.frame_length = silk_SMULBB( PacketSize_ms, fs_kHz );
209             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS_2_SF, fs_kHz );
210             if( psEnc->sCmn.fs_kHz == 8 ) {
211                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_NB_iCDF;
212             } else {
213                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_iCDF;
214             }
215         } else {
216             psEnc->sCmn.nFramesPerPacket = silk_DIV32_16( PacketSize_ms, MAX_FRAME_LENGTH_MS );
217             psEnc->sCmn.nb_subfr = MAX_NB_SUBFR;
218             psEnc->sCmn.frame_length = silk_SMULBB( 20, fs_kHz );
219             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS, fs_kHz );
220             if( psEnc->sCmn.fs_kHz == 8 ) {
221                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_NB_iCDF;
222             } else {
223                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_iCDF;
224             }
225         }
226         psEnc->sCmn.PacketSize_ms  = PacketSize_ms;
227         psEnc->sCmn.TargetRate_bps = 0;         /* trigger new SNR computation */
228     }
229
230     /* Set internal sampling frequency */
231     silk_assert( fs_kHz == 8 || fs_kHz == 12 || fs_kHz == 16 );
232     silk_assert( psEnc->sCmn.nb_subfr == 2 || psEnc->sCmn.nb_subfr == 4 );
233     if( psEnc->sCmn.fs_kHz != fs_kHz ) {
234         /* reset part of the state */
235         silk_memset( &psEnc->sShape,               0, sizeof( psEnc->sShape ) );
236         silk_memset( &psEnc->sPrefilt,             0, sizeof( psEnc->sPrefilt ) );
237         silk_memset( &psEnc->sCmn.sNSQ,            0, sizeof( psEnc->sCmn.sNSQ ) );
238         silk_memset( psEnc->sCmn.prev_NLSFq_Q15,   0, sizeof( psEnc->sCmn.prev_NLSFq_Q15 ) );
239         silk_memset( &psEnc->sCmn.sLP.In_LP_State, 0, sizeof( psEnc->sCmn.sLP.In_LP_State ) );
240         psEnc->sCmn.inputBufIx                  = 0;
241         psEnc->sCmn.nFramesEncoded              = 0;
242         psEnc->sCmn.TargetRate_bps              = 0;     /* trigger new SNR computation */
243
244         /* Initialize non-zero parameters */
245         psEnc->sCmn.prevLag                     = 100;
246         psEnc->sCmn.first_frame_after_reset     = 1;
247         psEnc->sPrefilt.lagPrev                 = 100;
248         psEnc->sShape.LastGainIndex             = 10;
249         psEnc->sCmn.sNSQ.lagPrev                = 100;
250         psEnc->sCmn.sNSQ.prev_gain_Q16          = 65536;
251         psEnc->sCmn.prevSignalType              = TYPE_NO_VOICE_ACTIVITY;
252
253         psEnc->sCmn.fs_kHz = fs_kHz;
254         if( psEnc->sCmn.fs_kHz == 8 ) {
255             if( psEnc->sCmn.nb_subfr == MAX_NB_SUBFR ) {
256                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_NB_iCDF;
257             } else {
258                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_NB_iCDF;
259             }
260         } else {
261             if( psEnc->sCmn.nb_subfr == MAX_NB_SUBFR ) {
262                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_iCDF;
263             } else {
264                 psEnc->sCmn.pitch_contour_iCDF = silk_pitch_contour_10_ms_iCDF;
265             }
266         }
267         if( psEnc->sCmn.fs_kHz == 8 || psEnc->sCmn.fs_kHz == 12 ) {
268             psEnc->sCmn.predictLPCOrder = MIN_LPC_ORDER;
269             psEnc->sCmn.psNLSF_CB  = &silk_NLSF_CB_NB_MB;
270         } else {
271             psEnc->sCmn.predictLPCOrder = MAX_LPC_ORDER;
272             psEnc->sCmn.psNLSF_CB  = &silk_NLSF_CB_WB;
273         }
274         psEnc->sCmn.subfr_length   = SUB_FRAME_LENGTH_MS * fs_kHz;
275         psEnc->sCmn.frame_length   = silk_SMULBB( psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr );
276         psEnc->sCmn.ltp_mem_length = silk_SMULBB( LTP_MEM_LENGTH_MS, fs_kHz );
277         psEnc->sCmn.la_pitch       = silk_SMULBB( LA_PITCH_MS, fs_kHz );
278         psEnc->sCmn.max_pitch_lag  = silk_SMULBB( 18, fs_kHz );
279         if( psEnc->sCmn.nb_subfr == MAX_NB_SUBFR ) {
280             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS, fs_kHz );
281         } else {
282             psEnc->sCmn.pitch_LPC_win_length = silk_SMULBB( FIND_PITCH_LPC_WIN_MS_2_SF, fs_kHz );
283         }
284         if( psEnc->sCmn.fs_kHz == 16 ) {
285             psEnc->sCmn.mu_LTP_Q9 = SILK_FIX_CONST( MU_LTP_QUANT_WB, 9 );
286             psEnc->sCmn.pitch_lag_low_bits_iCDF = silk_uniform8_iCDF;
287         } else if( psEnc->sCmn.fs_kHz == 12 ) {
288             psEnc->sCmn.mu_LTP_Q9 = SILK_FIX_CONST( MU_LTP_QUANT_MB, 9 );
289             psEnc->sCmn.pitch_lag_low_bits_iCDF = silk_uniform6_iCDF;
290         } else {
291             psEnc->sCmn.mu_LTP_Q9 = SILK_FIX_CONST( MU_LTP_QUANT_NB, 9 );
292             psEnc->sCmn.pitch_lag_low_bits_iCDF = silk_uniform4_iCDF;
293         }
294     }
295
296     /* Check that settings are valid */
297     silk_assert( ( psEnc->sCmn.subfr_length * psEnc->sCmn.nb_subfr ) == psEnc->sCmn.frame_length );
298
299     return ret;
300 }
301
302 static opus_int silk_setup_complexity(
303     silk_encoder_state              *psEncC,            /* I/O                      */
304     opus_int                        Complexity          /* I                        */
305 )
306 {
307     opus_int ret = 0;
308
309     /* Set encoding complexity */
310     silk_assert( Complexity >= 0 && Complexity <= 10 );
311     if( Complexity < 2 ) {
312         psEncC->pitchEstimationComplexity       = SILK_PE_MIN_COMPLEX;
313         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.8, 16 );
314         psEncC->pitchEstimationLPCOrder         = 6;
315         psEncC->shapingLPCOrder                 = 8;
316         psEncC->la_shape                        = 3 * psEncC->fs_kHz;
317         psEncC->nStatesDelayedDecision          = 1;
318         psEncC->useInterpolatedNLSFs            = 0;
319         psEncC->LTPQuantLowComplexity           = 1;
320         psEncC->NLSF_MSVQ_Survivors             = 2;
321         psEncC->warping_Q16                     = 0;
322     } else if( Complexity < 4 ) {
323         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
324         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.76, 16 );
325         psEncC->pitchEstimationLPCOrder         = 8;
326         psEncC->shapingLPCOrder                 = 10;
327         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
328         psEncC->nStatesDelayedDecision          = 1;
329         psEncC->useInterpolatedNLSFs            = 0;
330         psEncC->LTPQuantLowComplexity           = 0;
331         psEncC->NLSF_MSVQ_Survivors             = 4;
332         psEncC->warping_Q16                     = 0;
333     } else if( Complexity < 6 ) {
334         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
335         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.74, 16 );
336         psEncC->pitchEstimationLPCOrder         = 10;
337         psEncC->shapingLPCOrder                 = 12;
338         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
339         psEncC->nStatesDelayedDecision          = 2;
340         psEncC->useInterpolatedNLSFs            = 1;
341         psEncC->LTPQuantLowComplexity           = 0;
342         psEncC->NLSF_MSVQ_Survivors             = 8;
343         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
344     } else if( Complexity < 8 ) {
345         psEncC->pitchEstimationComplexity       = SILK_PE_MID_COMPLEX;
346         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.72, 16 );
347         psEncC->pitchEstimationLPCOrder         = 12;
348         psEncC->shapingLPCOrder                 = 14;
349         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
350         psEncC->nStatesDelayedDecision          = 3;
351         psEncC->useInterpolatedNLSFs            = 1;
352         psEncC->LTPQuantLowComplexity           = 0;
353         psEncC->NLSF_MSVQ_Survivors             = 16;
354         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
355     } else {
356         psEncC->pitchEstimationComplexity       = SILK_PE_MAX_COMPLEX;
357         psEncC->pitchEstimationThreshold_Q16    = SILK_FIX_CONST( 0.7, 16 );
358         psEncC->pitchEstimationLPCOrder         = 16;
359         psEncC->shapingLPCOrder                 = 16;
360         psEncC->la_shape                        = 5 * psEncC->fs_kHz;
361         psEncC->nStatesDelayedDecision          = MAX_DEL_DEC_STATES;
362         psEncC->useInterpolatedNLSFs            = 1;
363         psEncC->LTPQuantLowComplexity           = 0;
364         psEncC->NLSF_MSVQ_Survivors             = 32;
365         psEncC->warping_Q16                     = psEncC->fs_kHz * SILK_FIX_CONST( WARPING_MULTIPLIER, 16 );
366     }
367
368     /* Do not allow higher pitch estimation LPC order than predict LPC order */
369     psEncC->pitchEstimationLPCOrder = silk_min_int( psEncC->pitchEstimationLPCOrder, psEncC->predictLPCOrder );
370     psEncC->shapeWinLength          = SUB_FRAME_LENGTH_MS * psEncC->fs_kHz + 2 * psEncC->la_shape;
371     psEncC->Complexity              = Complexity;
372
373     silk_assert( psEncC->pitchEstimationLPCOrder <= MAX_FIND_PITCH_LPC_ORDER );
374     silk_assert( psEncC->shapingLPCOrder         <= MAX_SHAPE_LPC_ORDER      );
375     silk_assert( psEncC->nStatesDelayedDecision  <= MAX_DEL_DEC_STATES       );
376     silk_assert( psEncC->warping_Q16             <= 32767                    );
377     silk_assert( psEncC->la_shape                <= LA_SHAPE_MAX             );
378     silk_assert( psEncC->shapeWinLength          <= SHAPE_LPC_WIN_MAX        );
379     silk_assert( psEncC->NLSF_MSVQ_Survivors     <= NLSF_VQ_MAX_SURVIVORS    );
380
381     return ret;
382 }
383
384 static inline opus_int silk_setup_LBRR(
385     silk_encoder_state          *psEncC,            /* I/O                      */
386     const opus_int32            TargetRate_bps      /* I                        */
387 )
388 {
389     opus_int   ret = SILK_NO_ERROR;
390     opus_int32 LBRR_rate_thres_bps;
391
392     psEncC->LBRR_enabled = 0;
393     if( psEncC->useInBandFEC && psEncC->PacketLoss_perc > 0 ) {
394         if( psEncC->fs_kHz == 8 ) {
395             LBRR_rate_thres_bps = LBRR_NB_MIN_RATE_BPS;
396         } else if( psEncC->fs_kHz == 12 ) {
397             LBRR_rate_thres_bps = LBRR_MB_MIN_RATE_BPS;
398         } else {
399             LBRR_rate_thres_bps = LBRR_WB_MIN_RATE_BPS;
400         }
401         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 ) );
402
403         if( TargetRate_bps > LBRR_rate_thres_bps ) {
404             /* Set gain increase for coding LBRR excitation */
405             psEncC->LBRR_enabled = 1;
406             psEncC->LBRR_GainIncreases = silk_max_int( 7 - silk_SMULWB( (opus_int32)psEncC->PacketLoss_perc, SILK_FIX_CONST( 0.4, 16 ) ), 2 );
407         }
408     }
409
410     return ret;
411 }