michael@0: /***********************************************************************
michael@0: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
michael@0: Redistribution and use in source and binary forms, with or without
michael@0: modification, are permitted provided that the following conditions
michael@0: are met:
michael@0: - Redistributions of source code must retain the above copyright notice,
michael@0: this list of conditions and the following disclaimer.
michael@0: - Redistributions in binary form must reproduce the above copyright
michael@0: notice, this list of conditions and the following disclaimer in the
michael@0: documentation and/or other materials provided with the distribution.
michael@0: - Neither the name of Internet Society, IETF or IETF Trust, nor the
michael@0: names of specific contributors, may be used to endorse or promote
michael@0: products derived from this software without specific prior written
michael@0: permission.
michael@0: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
michael@0: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
michael@0: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
michael@0: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
michael@0: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
michael@0: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
michael@0: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
michael@0: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
michael@0: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
michael@0: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
michael@0: POSSIBILITY OF SUCH DAMAGE.
michael@0: ***********************************************************************/
michael@0: 
michael@0: #ifdef HAVE_CONFIG_H
michael@0: #include "config.h"
michael@0: #endif
michael@0: 
michael@0: /*
michael@0:  * Matrix of resampling methods used:
michael@0:  *                                 Fs_out (kHz)
michael@0:  *                        8      12     16     24     48
michael@0:  *
michael@0:  *               8        C      UF     U      UF     UF
michael@0:  *              12        AF     C      UF     U      UF
michael@0:  * Fs_in (kHz)  16        D      AF     C      UF     UF
michael@0:  *              24        AF     D      AF     C      U
michael@0:  *              48        AF     AF     AF     D      C
michael@0:  *
michael@0:  * C   -> Copy (no resampling)
michael@0:  * D   -> Allpass-based 2x downsampling
michael@0:  * U   -> Allpass-based 2x upsampling
michael@0:  * UF  -> Allpass-based 2x upsampling followed by FIR interpolation
michael@0:  * AF  -> AR2 filter followed by FIR interpolation
michael@0:  */
michael@0: 
michael@0: #include "resampler_private.h"
michael@0: 
michael@0: /* Tables with delay compensation values to equalize total delay for different modes */
michael@0: static const opus_int8 delay_matrix_enc[ 5 ][ 3 ] = {
michael@0: /* in  \ out  8  12  16 */
michael@0: /*  8 */   {  6,  0,  3 },
michael@0: /* 12 */   {  0,  7,  3 },
michael@0: /* 16 */   {  0,  1, 10 },
michael@0: /* 24 */   {  0,  2,  6 },
michael@0: /* 48 */   { 18, 10, 12 }
michael@0: };
michael@0: 
michael@0: static const opus_int8 delay_matrix_dec[ 3 ][ 5 ] = {
michael@0: /* in  \ out  8  12  16  24  48 */
michael@0: /*  8 */   {  4,  0,  2,  0,  0 },
michael@0: /* 12 */   {  0,  9,  4,  7,  4 },
michael@0: /* 16 */   {  0,  3, 12,  7,  7 }
michael@0: };
michael@0: 
michael@0: /* Simple way to make [8000, 12000, 16000, 24000, 48000] to [0, 1, 2, 3, 4] */
michael@0: #define rateID(R) ( ( ( ((R)>>12) - ((R)>16000) ) >> ((R)>24000) ) - 1 )
michael@0: 
michael@0: #define USE_silk_resampler_copy                     (0)
michael@0: #define USE_silk_resampler_private_up2_HQ_wrapper   (1)
michael@0: #define USE_silk_resampler_private_IIR_FIR          (2)
michael@0: #define USE_silk_resampler_private_down_FIR         (3)
michael@0: 
michael@0: /* Initialize/reset the resampler state for a given pair of input/output sampling rates */
michael@0: opus_int silk_resampler_init(
michael@0:     silk_resampler_state_struct *S,                 /* I/O  Resampler state                                             */
michael@0:     opus_int32                  Fs_Hz_in,           /* I    Input sampling rate (Hz)                                    */
michael@0:     opus_int32                  Fs_Hz_out,          /* I    Output sampling rate (Hz)                                   */
michael@0:     opus_int                    forEnc              /* I    If 1: encoder; if 0: decoder                                */
michael@0: )
michael@0: {
michael@0:     opus_int up2x;
michael@0: 
michael@0:     /* Clear state */
michael@0:     silk_memset( S, 0, sizeof( silk_resampler_state_struct ) );
michael@0: 
michael@0:     /* Input checking */
michael@0:     if( forEnc ) {
michael@0:         if( ( Fs_Hz_in  != 8000 && Fs_Hz_in  != 12000 && Fs_Hz_in  != 16000 && Fs_Hz_in  != 24000 && Fs_Hz_in  != 48000 ) ||
michael@0:             ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 ) ) {
michael@0:             silk_assert( 0 );
michael@0:             return -1;
michael@0:         }
michael@0:         S->inputDelay = delay_matrix_enc[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ];
michael@0:     } else {
michael@0:         if( ( Fs_Hz_in  != 8000 && Fs_Hz_in  != 12000 && Fs_Hz_in  != 16000 ) ||
michael@0:             ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 && Fs_Hz_out != 24000 && Fs_Hz_out != 48000 ) ) {
michael@0:             silk_assert( 0 );
michael@0:             return -1;
michael@0:         }
michael@0:         S->inputDelay = delay_matrix_dec[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ];
michael@0:     }
michael@0: 
michael@0:     S->Fs_in_kHz  = silk_DIV32_16( Fs_Hz_in,  1000 );
michael@0:     S->Fs_out_kHz = silk_DIV32_16( Fs_Hz_out, 1000 );
michael@0: 
michael@0:     /* Number of samples processed per batch */
michael@0:     S->batchSize = S->Fs_in_kHz * RESAMPLER_MAX_BATCH_SIZE_MS;
michael@0: 
michael@0:     /* Find resampler with the right sampling ratio */
michael@0:     up2x = 0;
michael@0:     if( Fs_Hz_out > Fs_Hz_in ) {
michael@0:         /* Upsample */
michael@0:         if( Fs_Hz_out == silk_MUL( Fs_Hz_in, 2 ) ) {                            /* Fs_out : Fs_in = 2 : 1 */
michael@0:             /* Special case: directly use 2x upsampler */
michael@0:             S->resampler_function = USE_silk_resampler_private_up2_HQ_wrapper;
michael@0:         } else {
michael@0:             /* Default resampler */
michael@0:             S->resampler_function = USE_silk_resampler_private_IIR_FIR;
michael@0:             up2x = 1;
michael@0:         }
michael@0:     } else if ( Fs_Hz_out < Fs_Hz_in ) {
michael@0:         /* Downsample */
michael@0:          S->resampler_function = USE_silk_resampler_private_down_FIR;
michael@0:         if( silk_MUL( Fs_Hz_out, 4 ) == silk_MUL( Fs_Hz_in, 3 ) ) {             /* Fs_out : Fs_in = 3 : 4 */
michael@0:             S->FIR_Fracs = 3;
michael@0:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0;
michael@0:             S->Coefs = silk_Resampler_3_4_COEFS;
michael@0:         } else if( silk_MUL( Fs_Hz_out, 3 ) == silk_MUL( Fs_Hz_in, 2 ) ) {      /* Fs_out : Fs_in = 2 : 3 */
michael@0:             S->FIR_Fracs = 2;
michael@0:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0;
michael@0:             S->Coefs = silk_Resampler_2_3_COEFS;
michael@0:         } else if( silk_MUL( Fs_Hz_out, 2 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 2 */
michael@0:             S->FIR_Fracs = 1;
michael@0:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR1;
michael@0:             S->Coefs = silk_Resampler_1_2_COEFS;
michael@0:         } else if( silk_MUL( Fs_Hz_out, 3 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 3 */
michael@0:             S->FIR_Fracs = 1;
michael@0:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
michael@0:             S->Coefs = silk_Resampler_1_3_COEFS;
michael@0:         } else if( silk_MUL( Fs_Hz_out, 4 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 4 */
michael@0:             S->FIR_Fracs = 1;
michael@0:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
michael@0:             S->Coefs = silk_Resampler_1_4_COEFS;
michael@0:         } else if( silk_MUL( Fs_Hz_out, 6 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 6 */
michael@0:             S->FIR_Fracs = 1;
michael@0:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
michael@0:             S->Coefs = silk_Resampler_1_6_COEFS;
michael@0:         } else {
michael@0:             /* None available */
michael@0:             silk_assert( 0 );
michael@0:             return -1;
michael@0:         }
michael@0:     } else {
michael@0:         /* Input and output sampling rates are equal: copy */
michael@0:         S->resampler_function = USE_silk_resampler_copy;
michael@0:     }
michael@0: 
michael@0:     /* Ratio of input/output samples */
michael@0:     S->invRatio_Q16 = silk_LSHIFT32( silk_DIV32( silk_LSHIFT32( Fs_Hz_in, 14 + up2x ), Fs_Hz_out ), 2 );
michael@0:     /* Make sure the ratio is rounded up */
michael@0:     while( silk_SMULWW( S->invRatio_Q16, Fs_Hz_out ) < silk_LSHIFT32( Fs_Hz_in, up2x ) ) {
michael@0:         S->invRatio_Q16++;
michael@0:     }
michael@0: 
michael@0:     return 0;
michael@0: }
michael@0: 
michael@0: /* Resampler: convert from one sampling rate to another */
michael@0: /* Input and output sampling rate are at most 48000 Hz  */
michael@0: opus_int silk_resampler(
michael@0:     silk_resampler_state_struct *S,                 /* I/O  Resampler state                                             */
michael@0:     opus_int16                  out[],              /* O    Output signal                                               */
michael@0:     const opus_int16            in[],               /* I    Input signal                                                */
michael@0:     opus_int32                  inLen               /* I    Number of input samples                                     */
michael@0: )
michael@0: {
michael@0:     opus_int nSamples;
michael@0: 
michael@0:     /* Need at least 1 ms of input data */
michael@0:     silk_assert( inLen >= S->Fs_in_kHz );
michael@0:     /* Delay can't exceed the 1 ms of buffering */
michael@0:     silk_assert( S->inputDelay <= S->Fs_in_kHz );
michael@0: 
michael@0:     nSamples = S->Fs_in_kHz - S->inputDelay;
michael@0: 
michael@0:     /* Copy to delay buffer */
michael@0:     silk_memcpy( &S->delayBuf[ S->inputDelay ], in, nSamples * sizeof( opus_int16 ) );
michael@0: 
michael@0:     switch( S->resampler_function ) {
michael@0:         case USE_silk_resampler_private_up2_HQ_wrapper:
michael@0:             silk_resampler_private_up2_HQ_wrapper( S, out, S->delayBuf, S->Fs_in_kHz );
michael@0:             silk_resampler_private_up2_HQ_wrapper( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
michael@0:             break;
michael@0:         case USE_silk_resampler_private_IIR_FIR:
michael@0:             silk_resampler_private_IIR_FIR( S, out, S->delayBuf, S->Fs_in_kHz );
michael@0:             silk_resampler_private_IIR_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
michael@0:             break;
michael@0:         case USE_silk_resampler_private_down_FIR:
michael@0:             silk_resampler_private_down_FIR( S, out, S->delayBuf, S->Fs_in_kHz );
michael@0:             silk_resampler_private_down_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
michael@0:             break;
michael@0:         default:
michael@0:             silk_memcpy( out, S->delayBuf, S->Fs_in_kHz * sizeof( opus_int16 ) );
michael@0:             silk_memcpy( &out[ S->Fs_out_kHz ], &in[ nSamples ], ( inLen - S->Fs_in_kHz ) * sizeof( opus_int16 ) );
michael@0:     }
michael@0: 
michael@0:     /* Copy to delay buffer */
michael@0:     silk_memcpy( S->delayBuf, &in[ inLen - S->inputDelay ], S->inputDelay * sizeof( opus_int16 ) );
michael@0: 
michael@0:     return 0;
michael@0: }