Eliminate some unreachable cases from the cwrs code and fixup the
[opus.git] / silk / silk_dec_API.c
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2 Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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27
28 #ifdef HAVE_CONFIG_H
29 #include "config.h"
30 #endif
31 #include "silk_API.h"
32 #include "silk_main.h"
33
34 /************************/
35 /* Decoder Super Struct */
36 /************************/
37 typedef struct {
38     silk_decoder_state          channel_state[ DECODER_NUM_CHANNELS ];
39     stereo_dec_state                sStereo;
40     opus_int                         nChannelsAPI;
41     opus_int                         nChannelsInternal;
42 } silk_decoder;
43
44 /*********************/
45 /* Decoder functions */
46 /*********************/
47
48 opus_int silk_Get_Decoder_Size( opus_int32 *decSizeBytes )
49 {
50     opus_int ret = SILK_NO_ERROR;
51
52     *decSizeBytes = sizeof( silk_decoder );
53
54     return ret;
55 }
56
57 /* Reset decoder state */
58 opus_int silk_InitDecoder(
59     void* decState                                      /* I/O: State                                          */
60 )
61 {
62     opus_int n, ret = SILK_NO_ERROR;
63     silk_decoder_state *channel_state = ((silk_decoder *)decState)->channel_state;
64
65     for( n = 0; n < DECODER_NUM_CHANNELS; n++ ) {
66         ret  = silk_init_decoder( &channel_state[ n ] );
67     }
68
69     return ret;
70 }
71
72 /* Decode a frame */
73 opus_int silk_Decode(
74     void*                               decState,       /* I/O: State                                           */
75     silk_DecControlStruct*      decControl,     /* I/O: Control Structure                               */
76     opus_int                             lostFlag,       /* I:   0: no loss, 1 loss, 2 decode FEC                */
77     opus_int                             newPacketFlag,  /* I:   Indicates first decoder call for this packet    */
78     ec_dec                              *psRangeDec,    /* I/O  Compressor data structure                       */
79     opus_int16                           *samplesOut,    /* O:   Decoded output speech vector                    */
80     opus_int32                           *nSamplesOut    /* O:   Number of samples decoded                       */
81 )
82 {
83     opus_int   i, n, prev_fs_kHz, decode_only_middle = 0, ret = SILK_NO_ERROR;
84     opus_int32 nSamplesOutDec, LBRR_symbol;
85     opus_int16 samplesOut1_tmp[ 2 ][ MAX_FS_KHZ * MAX_FRAME_LENGTH_MS + 2 ];
86     opus_int16 samplesOut2_tmp[ MAX_API_FS_KHZ * MAX_FRAME_LENGTH_MS ];
87     opus_int   MS_pred_Q13[ 2 ] = { 0 };
88     opus_int16 *resample_out_ptr;
89     silk_decoder *psDec = ( silk_decoder * )decState;
90     silk_decoder_state *channel_state = psDec->channel_state;
91
92     /**********************************/
93     /* Test if first frame in payload */
94     /**********************************/
95     if( newPacketFlag ) {
96         for( n = 0; n < decControl->nChannelsInternal; n++ ) {
97             channel_state[ n ].nFramesDecoded = 0;  /* Used to count frames in packet */
98         }
99     }
100
101     /* Save previous sample frequency */
102     prev_fs_kHz = channel_state[ 0 ].fs_kHz;
103
104     /* If Mono -> Stereo transition in bitstream: init state of second channel */
105     if( decControl->nChannelsInternal > psDec->nChannelsInternal ) {
106         ret += silk_init_decoder( &channel_state[ 1 ] );
107         if( psDec->nChannelsAPI == 2 ) {
108             SKP_memcpy( &channel_state[ 1 ].resampler_state, &channel_state[ 0 ].resampler_state, sizeof( silk_resampler_state_struct ) );
109         }
110     }
111
112     for( n = 0; n < decControl->nChannelsInternal; n++ ) {
113         if( channel_state[ n ].nFramesDecoded == 0 ) {
114             opus_int fs_kHz_dec;
115             if( decControl->payloadSize_ms == 0 ) {
116                 /* Assuming packet loss, use 10 ms */
117                 channel_state[ n ].nFramesPerPacket = 1;
118                 channel_state[ n ].nb_subfr = 2;
119             } else if( decControl->payloadSize_ms == 10 ) {
120                 channel_state[ n ].nFramesPerPacket = 1;
121                 channel_state[ n ].nb_subfr = 2;
122             } else if( decControl->payloadSize_ms == 20 ) {
123                 channel_state[ n ].nFramesPerPacket = 1;
124                 channel_state[ n ].nb_subfr = 4;
125             } else if( decControl->payloadSize_ms == 40 ) {
126                 channel_state[ n ].nFramesPerPacket = 2;
127                 channel_state[ n ].nb_subfr = 4;
128             } else if( decControl->payloadSize_ms == 60 ) {
129                 channel_state[ n ].nFramesPerPacket = 3;
130                 channel_state[ n ].nb_subfr = 4;
131             } else {
132                 SKP_assert( 0 );
133                 return SILK_DEC_INVALID_FRAME_SIZE;
134             }
135             fs_kHz_dec = ( decControl->internalSampleRate >> 10 ) + 1;
136             if( fs_kHz_dec != 8 && fs_kHz_dec != 12 && fs_kHz_dec != 16 ) {
137                 SKP_assert( 0 );
138                 return SILK_DEC_INVALID_SAMPLING_FREQUENCY;
139             }
140             silk_decoder_set_fs( &channel_state[ n ], fs_kHz_dec );
141         }
142     }
143
144     /* Initialize resampler when switching internal or external sampling frequency */
145     if( prev_fs_kHz != channel_state[ 0 ].fs_kHz || channel_state[ 0 ].prev_API_sampleRate != decControl->API_sampleRate ) {
146         ret = silk_resampler_init( &channel_state[ 0 ].resampler_state, SKP_SMULBB( channel_state[ 0 ].fs_kHz, 1000 ), decControl->API_sampleRate );
147         if( decControl->nChannelsAPI == 2 && decControl->nChannelsInternal == 2 ) {
148             SKP_memcpy( &channel_state[ 1 ].resampler_state, &channel_state[ 0 ].resampler_state, sizeof( silk_resampler_state_struct ) );
149         }
150     }
151     channel_state[ 0 ].prev_API_sampleRate = decControl->API_sampleRate;
152     if( decControl->nChannelsAPI == 2 && decControl->nChannelsInternal == 2 && ( psDec->nChannelsAPI == 1 || psDec->nChannelsInternal == 1 ) ) {
153         SKP_memset( psDec->sStereo.pred_prev_Q13, 0, sizeof( psDec->sStereo.pred_prev_Q13 ) );
154         SKP_memset( psDec->sStereo.sSide, 0, sizeof( psDec->sStereo.sSide ) );
155     }
156     psDec->nChannelsAPI      = decControl->nChannelsAPI;
157     psDec->nChannelsInternal = decControl->nChannelsInternal;
158
159     if( decControl->API_sampleRate > MAX_API_FS_KHZ * 1000 || decControl->API_sampleRate < 8000 ) {
160         ret = SILK_DEC_INVALID_SAMPLING_FREQUENCY;
161         return( ret );
162     }
163
164     if( lostFlag != FLAG_PACKET_LOST && channel_state[ 0 ].nFramesDecoded == 0 ) {
165         /* First decoder call for this payload */
166         /* Decode VAD flags and LBRR flag */
167         for( n = 0; n < decControl->nChannelsInternal; n++ ) {
168             for( i = 0; i < channel_state[ n ].nFramesPerPacket; i++ ) {
169                 channel_state[ n ].VAD_flags[ i ] = ec_dec_bit_logp(psRangeDec, 1);
170             }
171             channel_state[ n ].LBRR_flag = ec_dec_bit_logp(psRangeDec, 1);
172         }
173         /* Decode LBRR flags */
174         for( n = 0; n < decControl->nChannelsInternal; n++ ) {
175             SKP_memset( channel_state[ n ].LBRR_flags, 0, sizeof( channel_state[ n ].LBRR_flags ) );
176             if( channel_state[ n ].LBRR_flag ) {
177                 if( channel_state[ n ].nFramesPerPacket == 1 ) {
178                     channel_state[ n ].LBRR_flags[ 0 ] = 1;
179                 } else {
180                     LBRR_symbol = ec_dec_icdf( psRangeDec, silk_LBRR_flags_iCDF_ptr[ channel_state[ n ].nFramesPerPacket - 2 ], 8 ) + 1;
181                     for( i = 0; i < channel_state[ n ].nFramesPerPacket; i++ ) {
182                         channel_state[ n ].LBRR_flags[ i ] = SKP_RSHIFT( LBRR_symbol, i ) & 1;
183                     }
184                 }
185             }
186         }
187
188         if( lostFlag == FLAG_DECODE_NORMAL ) {
189             /* Regular decoding: skip all LBRR data */
190             for( i = 0; i < channel_state[ 0 ].nFramesPerPacket; i++ ) {
191                 for( n = 0; n < decControl->nChannelsInternal; n++ ) {
192                     if( channel_state[ n ].LBRR_flags[ i ] ) {
193                         opus_int pulses[ MAX_FRAME_LENGTH ];
194                         if( decControl->nChannelsInternal == 2 && n == 0 ) {
195                             silk_stereo_decode_pred( psRangeDec, &decode_only_middle, MS_pred_Q13 );
196                         }
197                         silk_decode_indices( &channel_state[ n ], psRangeDec, i, 1 );
198                         silk_decode_pulses( psRangeDec, pulses, channel_state[ n ].indices.signalType,
199                             channel_state[ n ].indices.quantOffsetType, channel_state[ n ].frame_length );
200                     }
201                 }
202             }
203         }
204     }
205
206     /* Get MS predictor index */
207     if( decControl->nChannelsInternal == 2 ) {
208         if(   lostFlag == FLAG_DECODE_NORMAL ||
209             ( lostFlag == FLAG_DECODE_LBRR && channel_state[ 0 ].LBRR_flags[ channel_state[ 0 ].nFramesDecoded ] == 1 ) )
210         {
211             silk_stereo_decode_pred( psRangeDec, &decode_only_middle, MS_pred_Q13 );
212         } else {
213             SKP_memcpy( MS_pred_Q13, &psDec->sStereo.pred_prev_Q13, sizeof( MS_pred_Q13 ) );
214         }
215     }
216
217     /* Call decoder for one frame */
218     for( n = 0; n < decControl->nChannelsInternal; n++ ) {
219         if( n == 0 || decode_only_middle == 0 ) {
220             ret += silk_decode_frame( &channel_state[ n ], psRangeDec, &samplesOut1_tmp[ n ][ 2 ], &nSamplesOutDec, lostFlag );
221         } else {
222             SKP_memset( &samplesOut1_tmp[ n ][ 2 ], 0, nSamplesOutDec * sizeof( opus_int16 ) );
223         }
224     }
225
226     if( decControl->nChannelsAPI == 2 && decControl->nChannelsInternal == 2 ) {
227         /* Convert Mid/Side to Left/Right */
228         silk_stereo_MS_to_LR( &psDec->sStereo, samplesOut1_tmp[ 0 ], samplesOut1_tmp[ 1 ], MS_pred_Q13, channel_state[ 0 ].fs_kHz, nSamplesOutDec );
229     } else {
230         /* Buffering */
231         SKP_memcpy( samplesOut1_tmp[ 0 ], psDec->sStereo.sMid, 2 * sizeof( opus_int16 ) );
232         SKP_memcpy( psDec->sStereo.sMid, &samplesOut1_tmp[ 0 ][ nSamplesOutDec ], 2 * sizeof( opus_int16 ) );
233     }
234
235     /* Number of output samples */
236     *nSamplesOut = SKP_DIV32( nSamplesOutDec * decControl->API_sampleRate, SKP_SMULBB( channel_state[ 0 ].fs_kHz, 1000 ) );
237
238     /* Set up pointers to temp buffers */
239     if( decControl->nChannelsAPI == 2 ) {
240         resample_out_ptr = samplesOut2_tmp;
241     } else {
242         resample_out_ptr = samplesOut;
243     }
244
245     for( n = 0; n < SKP_min( decControl->nChannelsAPI, decControl->nChannelsInternal ); n++ ) {
246         /* Resample decoded signal to API_sampleRate */
247         ret += silk_resampler( &channel_state[ n ].resampler_state, resample_out_ptr, &samplesOut1_tmp[ n ][ 1 ], nSamplesOutDec );
248
249         /* Interleave if stereo output and stereo stream */
250         if( decControl->nChannelsAPI == 2 && decControl->nChannelsInternal == 2 ) {
251             for( i = 0; i < *nSamplesOut; i++ ) {
252                 samplesOut[ n + 2 * i ] = resample_out_ptr[ i ];
253             }
254         }
255     }
256
257     /* Create two channel output from mono stream */
258     if( decControl->nChannelsAPI == 2 && decControl->nChannelsInternal == 1 ) {
259         for( i = 0; i < *nSamplesOut; i++ ) {
260             samplesOut[ 0 + 2 * i ] = samplesOut[ 1 + 2 * i ] = resample_out_ptr[ i ];
261         }
262     }
263
264     return ret;
265 }
266
267 /* Getting table of contents for a packet */
268 opus_int silk_get_TOC(
269     const opus_uint8                     *payload,           /* I    Payload data                                */
270     const opus_int                       nBytesIn,           /* I:   Number of input bytes                       */
271     const opus_int                       nFramesPerPayload,  /* I:   Number of SILK frames per payload           */
272     silk_TOC_struct                 *Silk_TOC           /* O:   Type of content                             */
273 )
274 {
275     opus_int i, flags, ret = SILK_NO_ERROR;
276
277     if( nBytesIn < 1 ) {
278         return -1;
279     }
280     if( nFramesPerPayload < 0 || nFramesPerPayload > 3 ) {
281         return -1;
282     }
283
284     SKP_memset( Silk_TOC, 0, sizeof( Silk_TOC ) );
285
286     /* For stereo, extract the flags for the mid channel */
287     flags = SKP_RSHIFT( payload[ 0 ], 7 - nFramesPerPayload ) & ( SKP_LSHIFT( 1, nFramesPerPayload + 1 ) - 1 );
288
289     Silk_TOC->inbandFECFlag = flags & 1;
290     for( i = nFramesPerPayload - 1; i >= 0 ; i-- ) {
291         flags = SKP_RSHIFT( flags, 1 );
292         Silk_TOC->VADFlags[ i ] = flags & 1;
293         Silk_TOC->VADFlag |= flags & 1;
294     }
295
296     return ret;
297 }