media/libopus/silk/resampler.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
  32 /*
  33  * Matrix of resampling methods used:
  34  *                                 Fs_out (kHz)
  35  *                        8      12     16     24     48
  36  *
  37  *               8        C      UF     U      UF     UF
  38  *              12        AF     C      UF     U      UF
  39  * Fs_in (kHz)  16        D      AF     C      UF     UF
  40  *              24        AF     D      AF     C      U
  41  *              48        AF     AF     AF     D      C
  42  *
  43  * C   -> Copy (no resampling)
  44  * D   -> Allpass-based 2x downsampling
  45  * U   -> Allpass-based 2x upsampling
  46  * UF  -> Allpass-based 2x upsampling followed by FIR interpolation
  47  * AF  -> AR2 filter followed by FIR interpolation
  48  */
  49
  50 #include "resampler_private.h"
  51
  52 /* Tables with delay compensation values to equalize total delay for different modes */
  53 static const opus_int8 delay_matrix_enc[ 5 ][ 3 ] = {
  54 /* in  \ out  8  12  16 */
  55 /*  8 */   {  6,  0,  3 },
  56 /* 12 */   {  0,  7,  3 },
  57 /* 16 */   {  0,  1, 10 },
  58 /* 24 */   {  0,  2,  6 },
  59 /* 48 */   { 18, 10, 12 }
  60 };
  61
  62 static const opus_int8 delay_matrix_dec[ 3 ][ 5 ] = {
  63 /* in  \ out  8  12  16  24  48 */
  64 /*  8 */   {  4,  0,  2,  0,  0 },
  65 /* 12 */   {  0,  9,  4,  7,  4 },
  66 /* 16 */   {  0,  3, 12,  7,  7 }
  67 };
  68
  69 /* Simple way to make [8000, 12000, 16000, 24000, 48000] to [0, 1, 2, 3, 4] */
  70 #define rateID(R) ( ( ( ((R)>>12) - ((R)>16000) ) >> ((R)>24000) ) - 1 )
  71
  72 #define USE_silk_resampler_copy                     (0)
  73 #define USE_silk_resampler_private_up2_HQ_wrapper   (1)
  74 #define USE_silk_resampler_private_IIR_FIR          (2)
  75 #define USE_silk_resampler_private_down_FIR         (3)
  76
  77 /* Initialize/reset the resampler state for a given pair of input/output sampling rates */
  78 opus_int silk_resampler_init(
  79     silk_resampler_state_struct *S,                 /* I/O  Resampler state                                             */
  80     opus_int32                  Fs_Hz_in,           /* I    Input sampling rate (Hz)                                    */
  81     opus_int32                  Fs_Hz_out,          /* I    Output sampling rate (Hz)                                   */
  82     opus_int                    forEnc              /* I    If 1: encoder; if 0: decoder                                */
  83 )
  84 {
  85     opus_int up2x;
  86
  87     /* Clear state */
  88     silk_memset( S, 0, sizeof( silk_resampler_state_struct ) );
  89
  90     /* Input checking */
  91     if( forEnc ) {
  92         if( ( Fs_Hz_in  != 8000 && Fs_Hz_in  != 12000 && Fs_Hz_in  != 16000 && Fs_Hz_in  != 24000 && Fs_Hz_in  != 48000 ) ||
  93             ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 ) ) {
  94             celt_assert( 0 );
  95             return -1;
  96         }
  97         S->inputDelay = delay_matrix_enc[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ];
  98     } else {
  99         if( ( Fs_Hz_in  != 8000 && Fs_Hz_in  != 12000 && Fs_Hz_in  != 16000 ) ||
 100             ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 && Fs_Hz_out != 24000 && Fs_Hz_out != 48000 ) ) {
 101             celt_assert( 0 );
 102             return -1;
 103         }
 104         S->inputDelay = delay_matrix_dec[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ];
 105     }
 106
 107     S->Fs_in_kHz  = silk_DIV32_16( Fs_Hz_in,  1000 );
 108     S->Fs_out_kHz = silk_DIV32_16( Fs_Hz_out, 1000 );
 109
 110     /* Number of samples processed per batch */
 111     S->batchSize = S->Fs_in_kHz * RESAMPLER_MAX_BATCH_SIZE_MS;
 112
 113     /* Find resampler with the right sampling ratio */
 114     up2x = 0;
 115     if( Fs_Hz_out > Fs_Hz_in ) {
 116         /* Upsample */
 117         if( Fs_Hz_out == silk_MUL( Fs_Hz_in, 2 ) ) {                            /* Fs_out : Fs_in = 2 : 1 */
 118             /* Special case: directly use 2x upsampler */
 119             S->resampler_function = USE_silk_resampler_private_up2_HQ_wrapper;
 120         } else {
 121             /* Default resampler */
 122             S->resampler_function = USE_silk_resampler_private_IIR_FIR;
 123             up2x = 1;
 124         }
 125     } else if ( Fs_Hz_out < Fs_Hz_in ) {
 126         /* Downsample */
 127          S->resampler_function = USE_silk_resampler_private_down_FIR;
 128         if( silk_MUL( Fs_Hz_out, 4 ) == silk_MUL( Fs_Hz_in, 3 ) ) {             /* Fs_out : Fs_in = 3 : 4 */
 129             S->FIR_Fracs = 3;
 130             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0;
 131             S->Coefs = silk_Resampler_3_4_COEFS;
 132         } else if( silk_MUL( Fs_Hz_out, 3 ) == silk_MUL( Fs_Hz_in, 2 ) ) {      /* Fs_out : Fs_in = 2 : 3 */
 133             S->FIR_Fracs = 2;
 134             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0;
 135             S->Coefs = silk_Resampler_2_3_COEFS;
 136         } else if( silk_MUL( Fs_Hz_out, 2 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 2 */
 137             S->FIR_Fracs = 1;
 138             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR1;
 139             S->Coefs = silk_Resampler_1_2_COEFS;
 140         } else if( silk_MUL( Fs_Hz_out, 3 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 3 */
 141             S->FIR_Fracs = 1;
 142             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
 143             S->Coefs = silk_Resampler_1_3_COEFS;
 144         } else if( silk_MUL( Fs_Hz_out, 4 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 4 */
 145             S->FIR_Fracs = 1;
 146             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
 147             S->Coefs = silk_Resampler_1_4_COEFS;
 148         } else if( silk_MUL( Fs_Hz_out, 6 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 6 */
 149             S->FIR_Fracs = 1;
 150             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
 151             S->Coefs = silk_Resampler_1_6_COEFS;
 152         } else {
 153             /* None available */
 154             celt_assert( 0 );
 155             return -1;
 156         }
 157     } else {
 158         /* Input and output sampling rates are equal: copy */
 159         S->resampler_function = USE_silk_resampler_copy;
 160     }
 161
 162     /* Ratio of input/output samples */
 163     S->invRatio_Q16 = silk_LSHIFT32( silk_DIV32( silk_LSHIFT32( Fs_Hz_in, 14 + up2x ), Fs_Hz_out ), 2 );
 164     /* Make sure the ratio is rounded up */
 165     while( silk_SMULWW( S->invRatio_Q16, Fs_Hz_out ) < silk_LSHIFT32( Fs_Hz_in, up2x ) ) {
 166         S->invRatio_Q16++;
 167     }
 168
 169     return 0;
 170 }
 171
 172 /* Resampler: convert from one sampling rate to another */
 173 /* Input and output sampling rate are at most 48000 Hz  */
 174 opus_int silk_resampler(
 175     silk_resampler_state_struct *S,                 /* I/O  Resampler state                                             */
 176     opus_int16                  out[],              /* O    Output signal                                               */
 177     const opus_int16            in[],               /* I    Input signal                                                */
 178     opus_int32                  inLen               /* I    Number of input samples                                     */
 179 )
 180 {
 181     opus_int nSamples;
 182
 183     /* Need at least 1 ms of input data */
 184     celt_assert( inLen >= S->Fs_in_kHz );
 185     /* Delay can't exceed the 1 ms of buffering */
 186     celt_assert( S->inputDelay <= S->Fs_in_kHz );
 187
 188     nSamples = S->Fs_in_kHz - S->inputDelay;
 189
 190     /* Copy to delay buffer */
 191     silk_memcpy( &S->delayBuf[ S->inputDelay ], in, nSamples * sizeof( opus_int16 ) );
 192
 193     switch( S->resampler_function ) {
 194         case USE_silk_resampler_private_up2_HQ_wrapper:
 195             silk_resampler_private_up2_HQ_wrapper( S, out, S->delayBuf, S->Fs_in_kHz );
 196             silk_resampler_private_up2_HQ_wrapper( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
 197             break;
 198         case USE_silk_resampler_private_IIR_FIR:
 199             silk_resampler_private_IIR_FIR( S, out, S->delayBuf, S->Fs_in_kHz );
 200             silk_resampler_private_IIR_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
 201             break;
 202         case USE_silk_resampler_private_down_FIR:
 203             silk_resampler_private_down_FIR( S, out, S->delayBuf, S->Fs_in_kHz );
 204             silk_resampler_private_down_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
 205             break;
 206         default:
 207             silk_memcpy( out, S->delayBuf, S->Fs_in_kHz * sizeof( opus_int16 ) );
 208             silk_memcpy( &out[ S->Fs_out_kHz ], &in[ nSamples ], ( inLen - S->Fs_in_kHz ) * sizeof( opus_int16 ) );
 209     }
 210
 211     /* Copy to delay buffer */
 212     silk_memcpy( S->delayBuf, &in[ inLen - S->inputDelay ], S->inputDelay * sizeof( opus_int16 ) );
 213
 214     return 0;
 215 }