Chris@69: /***********************************************************************
Chris@69: Copyright (c) 2006-2011, Skype Limited. All rights reserved.
Chris@69: Redistribution and use in source and binary forms, with or without
Chris@69: modification, are permitted provided that the following conditions
Chris@69: are met:
Chris@69: - Redistributions of source code must retain the above copyright notice,
Chris@69: this list of conditions and the following disclaimer.
Chris@69: - Redistributions in binary form must reproduce the above copyright
Chris@69: notice, this list of conditions and the following disclaimer in the
Chris@69: documentation and/or other materials provided with the distribution.
Chris@69: - Neither the name of Internet Society, IETF or IETF Trust, nor the
Chris@69: names of specific contributors, may be used to endorse or promote
Chris@69: products derived from this software without specific prior written
Chris@69: permission.
Chris@69: THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
Chris@69: AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
Chris@69: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
Chris@69: ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
Chris@69: LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
Chris@69: CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
Chris@69: SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
Chris@69: INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
Chris@69: CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
Chris@69: ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
Chris@69: POSSIBILITY OF SUCH DAMAGE.
Chris@69: ***********************************************************************/
Chris@69: 
Chris@69: #ifdef HAVE_CONFIG_H
Chris@69: #include "config.h"
Chris@69: #endif
Chris@69: 
Chris@69: /*
Chris@69:  * Matrix of resampling methods used:
Chris@69:  *                                 Fs_out (kHz)
Chris@69:  *                        8      12     16     24     48
Chris@69:  *
Chris@69:  *               8        C      UF     U      UF     UF
Chris@69:  *              12        AF     C      UF     U      UF
Chris@69:  * Fs_in (kHz)  16        D      AF     C      UF     UF
Chris@69:  *              24        AF     D      AF     C      U
Chris@69:  *              48        AF     AF     AF     D      C
Chris@69:  *
Chris@69:  * C   -> Copy (no resampling)
Chris@69:  * D   -> Allpass-based 2x downsampling
Chris@69:  * U   -> Allpass-based 2x upsampling
Chris@69:  * UF  -> Allpass-based 2x upsampling followed by FIR interpolation
Chris@69:  * AF  -> AR2 filter followed by FIR interpolation
Chris@69:  */
Chris@69: 
Chris@69: #include "resampler_private.h"
Chris@69: 
Chris@69: /* Tables with delay compensation values to equalize total delay for different modes */
Chris@69: static const opus_int8 delay_matrix_enc[ 5 ][ 3 ] = {
Chris@69: /* in  \ out  8  12  16 */
Chris@69: /*  8 */   {  6,  0,  3 },
Chris@69: /* 12 */   {  0,  7,  3 },
Chris@69: /* 16 */   {  0,  1, 10 },
Chris@69: /* 24 */   {  0,  2,  6 },
Chris@69: /* 48 */   { 18, 10, 12 }
Chris@69: };
Chris@69: 
Chris@69: static const opus_int8 delay_matrix_dec[ 3 ][ 5 ] = {
Chris@69: /* in  \ out  8  12  16  24  48 */
Chris@69: /*  8 */   {  4,  0,  2,  0,  0 },
Chris@69: /* 12 */   {  0,  9,  4,  7,  4 },
Chris@69: /* 16 */   {  0,  3, 12,  7,  7 }
Chris@69: };
Chris@69: 
Chris@69: /* Simple way to make [8000, 12000, 16000, 24000, 48000] to [0, 1, 2, 3, 4] */
Chris@69: #define rateID(R) ( ( ( ((R)>>12) - ((R)>16000) ) >> ((R)>24000) ) - 1 )
Chris@69: 
Chris@69: #define USE_silk_resampler_copy                     (0)
Chris@69: #define USE_silk_resampler_private_up2_HQ_wrapper   (1)
Chris@69: #define USE_silk_resampler_private_IIR_FIR          (2)
Chris@69: #define USE_silk_resampler_private_down_FIR         (3)
Chris@69: 
Chris@69: /* Initialize/reset the resampler state for a given pair of input/output sampling rates */
Chris@69: opus_int silk_resampler_init(
Chris@69:     silk_resampler_state_struct *S,                 /* I/O  Resampler state                                             */
Chris@69:     opus_int32                  Fs_Hz_in,           /* I    Input sampling rate (Hz)                                    */
Chris@69:     opus_int32                  Fs_Hz_out,          /* I    Output sampling rate (Hz)                                   */
Chris@69:     opus_int                    forEnc              /* I    If 1: encoder; if 0: decoder                                */
Chris@69: )
Chris@69: {
Chris@69:     opus_int up2x;
Chris@69: 
Chris@69:     /* Clear state */
Chris@69:     silk_memset( S, 0, sizeof( silk_resampler_state_struct ) );
Chris@69: 
Chris@69:     /* Input checking */
Chris@69:     if( forEnc ) {
Chris@69:         if( ( Fs_Hz_in  != 8000 && Fs_Hz_in  != 12000 && Fs_Hz_in  != 16000 && Fs_Hz_in  != 24000 && Fs_Hz_in  != 48000 ) ||
Chris@69:             ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 ) ) {
Chris@69:             celt_assert( 0 );
Chris@69:             return -1;
Chris@69:         }
Chris@69:         S->inputDelay = delay_matrix_enc[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ];
Chris@69:     } else {
Chris@69:         if( ( Fs_Hz_in  != 8000 && Fs_Hz_in  != 12000 && Fs_Hz_in  != 16000 ) ||
Chris@69:             ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 && Fs_Hz_out != 24000 && Fs_Hz_out != 48000 ) ) {
Chris@69:             celt_assert( 0 );
Chris@69:             return -1;
Chris@69:         }
Chris@69:         S->inputDelay = delay_matrix_dec[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ];
Chris@69:     }
Chris@69: 
Chris@69:     S->Fs_in_kHz  = silk_DIV32_16( Fs_Hz_in,  1000 );
Chris@69:     S->Fs_out_kHz = silk_DIV32_16( Fs_Hz_out, 1000 );
Chris@69: 
Chris@69:     /* Number of samples processed per batch */
Chris@69:     S->batchSize = S->Fs_in_kHz * RESAMPLER_MAX_BATCH_SIZE_MS;
Chris@69: 
Chris@69:     /* Find resampler with the right sampling ratio */
Chris@69:     up2x = 0;
Chris@69:     if( Fs_Hz_out > Fs_Hz_in ) {
Chris@69:         /* Upsample */
Chris@69:         if( Fs_Hz_out == silk_MUL( Fs_Hz_in, 2 ) ) {                            /* Fs_out : Fs_in = 2 : 1 */
Chris@69:             /* Special case: directly use 2x upsampler */
Chris@69:             S->resampler_function = USE_silk_resampler_private_up2_HQ_wrapper;
Chris@69:         } else {
Chris@69:             /* Default resampler */
Chris@69:             S->resampler_function = USE_silk_resampler_private_IIR_FIR;
Chris@69:             up2x = 1;
Chris@69:         }
Chris@69:     } else if ( Fs_Hz_out < Fs_Hz_in ) {
Chris@69:         /* Downsample */
Chris@69:          S->resampler_function = USE_silk_resampler_private_down_FIR;
Chris@69:         if( silk_MUL( Fs_Hz_out, 4 ) == silk_MUL( Fs_Hz_in, 3 ) ) {             /* Fs_out : Fs_in = 3 : 4 */
Chris@69:             S->FIR_Fracs = 3;
Chris@69:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0;
Chris@69:             S->Coefs = silk_Resampler_3_4_COEFS;
Chris@69:         } else if( silk_MUL( Fs_Hz_out, 3 ) == silk_MUL( Fs_Hz_in, 2 ) ) {      /* Fs_out : Fs_in = 2 : 3 */
Chris@69:             S->FIR_Fracs = 2;
Chris@69:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0;
Chris@69:             S->Coefs = silk_Resampler_2_3_COEFS;
Chris@69:         } else if( silk_MUL( Fs_Hz_out, 2 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 2 */
Chris@69:             S->FIR_Fracs = 1;
Chris@69:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR1;
Chris@69:             S->Coefs = silk_Resampler_1_2_COEFS;
Chris@69:         } else if( silk_MUL( Fs_Hz_out, 3 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 3 */
Chris@69:             S->FIR_Fracs = 1;
Chris@69:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
Chris@69:             S->Coefs = silk_Resampler_1_3_COEFS;
Chris@69:         } else if( silk_MUL( Fs_Hz_out, 4 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 4 */
Chris@69:             S->FIR_Fracs = 1;
Chris@69:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
Chris@69:             S->Coefs = silk_Resampler_1_4_COEFS;
Chris@69:         } else if( silk_MUL( Fs_Hz_out, 6 ) == Fs_Hz_in ) {                     /* Fs_out : Fs_in = 1 : 6 */
Chris@69:             S->FIR_Fracs = 1;
Chris@69:             S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2;
Chris@69:             S->Coefs = silk_Resampler_1_6_COEFS;
Chris@69:         } else {
Chris@69:             /* None available */
Chris@69:             celt_assert( 0 );
Chris@69:             return -1;
Chris@69:         }
Chris@69:     } else {
Chris@69:         /* Input and output sampling rates are equal: copy */
Chris@69:         S->resampler_function = USE_silk_resampler_copy;
Chris@69:     }
Chris@69: 
Chris@69:     /* Ratio of input/output samples */
Chris@69:     S->invRatio_Q16 = silk_LSHIFT32( silk_DIV32( silk_LSHIFT32( Fs_Hz_in, 14 + up2x ), Fs_Hz_out ), 2 );
Chris@69:     /* Make sure the ratio is rounded up */
Chris@69:     while( silk_SMULWW( S->invRatio_Q16, Fs_Hz_out ) < silk_LSHIFT32( Fs_Hz_in, up2x ) ) {
Chris@69:         S->invRatio_Q16++;
Chris@69:     }
Chris@69: 
Chris@69:     return 0;
Chris@69: }
Chris@69: 
Chris@69: /* Resampler: convert from one sampling rate to another */
Chris@69: /* Input and output sampling rate are at most 48000 Hz  */
Chris@69: opus_int silk_resampler(
Chris@69:     silk_resampler_state_struct *S,                 /* I/O  Resampler state                                             */
Chris@69:     opus_int16                  out[],              /* O    Output signal                                               */
Chris@69:     const opus_int16            in[],               /* I    Input signal                                                */
Chris@69:     opus_int32                  inLen               /* I    Number of input samples                                     */
Chris@69: )
Chris@69: {
Chris@69:     opus_int nSamples;
Chris@69: 
Chris@69:     /* Need at least 1 ms of input data */
Chris@69:     celt_assert( inLen >= S->Fs_in_kHz );
Chris@69:     /* Delay can't exceed the 1 ms of buffering */
Chris@69:     celt_assert( S->inputDelay <= S->Fs_in_kHz );
Chris@69: 
Chris@69:     nSamples = S->Fs_in_kHz - S->inputDelay;
Chris@69: 
Chris@69:     /* Copy to delay buffer */
Chris@69:     silk_memcpy( &S->delayBuf[ S->inputDelay ], in, nSamples * sizeof( opus_int16 ) );
Chris@69: 
Chris@69:     switch( S->resampler_function ) {
Chris@69:         case USE_silk_resampler_private_up2_HQ_wrapper:
Chris@69:             silk_resampler_private_up2_HQ_wrapper( S, out, S->delayBuf, S->Fs_in_kHz );
Chris@69:             silk_resampler_private_up2_HQ_wrapper( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
Chris@69:             break;
Chris@69:         case USE_silk_resampler_private_IIR_FIR:
Chris@69:             silk_resampler_private_IIR_FIR( S, out, S->delayBuf, S->Fs_in_kHz );
Chris@69:             silk_resampler_private_IIR_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
Chris@69:             break;
Chris@69:         case USE_silk_resampler_private_down_FIR:
Chris@69:             silk_resampler_private_down_FIR( S, out, S->delayBuf, S->Fs_in_kHz );
Chris@69:             silk_resampler_private_down_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz );
Chris@69:             break;
Chris@69:         default:
Chris@69:             silk_memcpy( out, S->delayBuf, S->Fs_in_kHz * sizeof( opus_int16 ) );
Chris@69:             silk_memcpy( &out[ S->Fs_out_kHz ], &in[ nSamples ], ( inLen - S->Fs_in_kHz ) * sizeof( opus_int16 ) );
Chris@69:     }
Chris@69: 
Chris@69:     /* Copy to delay buffer */
Chris@69:     silk_memcpy( S->delayBuf, &in[ inLen - S->inputDelay ], S->inputDelay * sizeof( opus_int16 ) );
Chris@69: 
Chris@69:     return 0;
Chris@69: }