ref: 17c5966045b463fde45418000b03c95eb5cd7e09
dir: /silk/resampler.c/
/*********************************************************************** Copyright (c) 2006-2011, Skype Limited. All rights reserved. Redistribution and use in source and binary forms, with or without modification, (subject to the limitations in the disclaimer below) are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of Skype Limited, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission. NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. ***********************************************************************/ #ifdef HAVE_CONFIG_H #include "config.h" #endif /* * Matrix of resampling methods used: * Fs_out (kHz) * 8 12 16 24 48 * * 8 C UF U UF UF * 12 AF C UF U UF * Fs_in (kHz) 16 D AF C UF UF * 24 AF D AF C U * 48 AF AF AF D C * * C -> Copy (no resampling) * D -> Allpass-based 2x downsampling * U -> Allpass-based 2x upsampling * UF -> Allpass-based 2x upsampling followed by FIR interpolation * AF -> AR2 filter followed by FIR interpolation */ #include "resampler_private.h" /* Tables with delay compensation values to equalize total delay for different modes */ static const opus_int8 delay_matrix_enc[ 5 ][ 3 ] = { /* in \ out 8 12 16 */ /* 8 */ { 6, 0, 3 }, /* 12 */ { 0, 7, 3 }, /* 16 */ { 0, 1, 10 }, /* 24 */ { 0, 2, 6 }, /* 48 */ { 18, 10, 12 } }; static const opus_int8 delay_matrix_dec[ 3 ][ 5 ] = { /* in \ out 8 12 16 24 48 */ /* 8 */ { 4, 0, 2, 0, 0 }, /* 12 */ { 0, 9, 4, 7, 4 }, /* 16 */ { 0, 3, 12, 7, 7 } }; /* Simple way to make [8000, 12000, 16000, 24000, 48000] to [0, 1, 2, 3, 4] */ #define rateID(R) ( ( ( ((R)>>12) - ((R)>16000) ) >> ((R)>24000) ) - 1 ) #define USE_silk_resampler_copy (0) #define USE_silk_resampler_private_up2_HQ_wrapper (1) #define USE_silk_resampler_private_IIR_FIR (2) #define USE_silk_resampler_private_down_FIR (3) /* Initialize/reset the resampler state for a given pair of input/output sampling rates */ opus_int silk_resampler_init( silk_resampler_state_struct *S, /* I/O Resampler state */ opus_int32 Fs_Hz_in, /* I Input sampling rate (Hz) */ opus_int32 Fs_Hz_out, /* I Output sampling rate (Hz) */ opus_int forEnc /* I If 1: encoder; if 0: decoder */ ) { opus_int up2x; /* Clear state */ silk_memset( S, 0, sizeof( silk_resampler_state_struct ) ); /* Input checking */ if( forEnc ) { if( ( Fs_Hz_in != 8000 && Fs_Hz_in != 12000 && Fs_Hz_in != 16000 && Fs_Hz_in != 24000 && Fs_Hz_in != 48000 ) || ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 ) ) { silk_assert( 0 ); return -1; } S->inputDelay = delay_matrix_enc[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ]; } else { if( ( Fs_Hz_in != 8000 && Fs_Hz_in != 12000 && Fs_Hz_in != 16000 ) || ( Fs_Hz_out != 8000 && Fs_Hz_out != 12000 && Fs_Hz_out != 16000 && Fs_Hz_out != 24000 && Fs_Hz_out != 48000 ) ) { silk_assert( 0 ); return -1; } S->inputDelay = delay_matrix_dec[ rateID( Fs_Hz_in ) ][ rateID( Fs_Hz_out ) ]; } S->Fs_in_kHz = silk_DIV32_16( Fs_Hz_in, 1000 ); S->Fs_out_kHz = silk_DIV32_16( Fs_Hz_out, 1000 ); /* Number of samples processed per batch */ S->batchSize = S->Fs_in_kHz * RESAMPLER_MAX_BATCH_SIZE_MS; /* Find resampler with the right sampling ratio */ up2x = 0; if( Fs_Hz_out > Fs_Hz_in ) { /* Upsample */ if( Fs_Hz_out == silk_MUL( Fs_Hz_in, 2 ) ) { /* Fs_out : Fs_in = 2 : 1 */ /* Special case: directly use 2x upsampler */ S->resampler_function = USE_silk_resampler_private_up2_HQ_wrapper; } else { /* Default resampler */ S->resampler_function = USE_silk_resampler_private_IIR_FIR; up2x = 1; } } else if ( Fs_Hz_out < Fs_Hz_in ) { /* Downsample */ S->resampler_function = USE_silk_resampler_private_down_FIR; if( silk_MUL( Fs_Hz_out, 4 ) == silk_MUL( Fs_Hz_in, 3 ) ) { /* Fs_out : Fs_in = 3 : 4 */ S->FIR_Fracs = 3; S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0; S->Coefs = silk_Resampler_3_4_COEFS; } else if( silk_MUL( Fs_Hz_out, 3 ) == silk_MUL( Fs_Hz_in, 2 ) ) { /* Fs_out : Fs_in = 2 : 3 */ S->FIR_Fracs = 2; S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR0; S->Coefs = silk_Resampler_2_3_COEFS; } else if( silk_MUL( Fs_Hz_out, 2 ) == Fs_Hz_in ) { /* Fs_out : Fs_in = 1 : 2 */ S->FIR_Fracs = 1; S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR1; S->Coefs = silk_Resampler_1_2_COEFS; } else if( silk_MUL( Fs_Hz_out, 3 ) == Fs_Hz_in ) { /* Fs_out : Fs_in = 1 : 3 */ S->FIR_Fracs = 1; S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2; S->Coefs = silk_Resampler_1_3_COEFS; } else if( silk_MUL( Fs_Hz_out, 4 ) == Fs_Hz_in ) { /* Fs_out : Fs_in = 1 : 4 */ S->FIR_Fracs = 1; S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2; S->Coefs = silk_Resampler_1_4_COEFS; } else if( silk_MUL( Fs_Hz_out, 6 ) == Fs_Hz_in ) { /* Fs_out : Fs_in = 1 : 6 */ S->FIR_Fracs = 1; S->FIR_Order = RESAMPLER_DOWN_ORDER_FIR2; S->Coefs = silk_Resampler_1_6_COEFS; } else { /* None available */ silk_assert( 0 ); return -1; } } else { /* Input and output sampling rates are equal: copy */ S->resampler_function = USE_silk_resampler_copy; } /* Ratio of input/output samples */ S->invRatio_Q16 = silk_LSHIFT32( silk_DIV32( silk_LSHIFT32( Fs_Hz_in, 14 + up2x ), Fs_Hz_out ), 2 ); /* Make sure the ratio is rounded up */ while( silk_SMULWW( S->invRatio_Q16, Fs_Hz_out ) < silk_LSHIFT32( Fs_Hz_in, up2x ) ) { S->invRatio_Q16++; } return 0; } /* Resampler: convert from one sampling rate to another */ /* Input and output sampling rate are at most 48000 Hz */ opus_int silk_resampler( silk_resampler_state_struct *S, /* I/O Resampler state */ opus_int16 out[], /* O Output signal */ const opus_int16 in[], /* I Input signal */ opus_int32 inLen /* I Number of input samples */ ) { opus_int nSamples; /* Need at least 1 ms of input data */ silk_assert( inLen >= S->Fs_in_kHz ); /* Delay can't exceed the 1 ms of buffering */ silk_assert( S->inputDelay <= S->Fs_in_kHz ); nSamples = S->Fs_in_kHz - S->inputDelay; /* Copy to delay buffer */ silk_memcpy( &S->delayBuf[ S->inputDelay ], in, nSamples * sizeof( opus_int16 ) ); switch( S->resampler_function ) { case USE_silk_resampler_private_up2_HQ_wrapper: silk_resampler_private_up2_HQ_wrapper( S, out, S->delayBuf, S->Fs_in_kHz ); silk_resampler_private_up2_HQ_wrapper( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz ); break; case USE_silk_resampler_private_IIR_FIR: silk_resampler_private_IIR_FIR( S, out, S->delayBuf, S->Fs_in_kHz ); silk_resampler_private_IIR_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz ); break; case USE_silk_resampler_private_down_FIR: silk_resampler_private_down_FIR( S, out, S->delayBuf, S->Fs_in_kHz ); silk_resampler_private_down_FIR( S, &out[ S->Fs_out_kHz ], &in[ nSamples ], inLen - S->Fs_in_kHz ); break; default: silk_memcpy( out, S->delayBuf, S->Fs_in_kHz * sizeof( opus_int16 ) ); silk_memcpy( &out[ S->Fs_out_kHz ], &in[ nSamples ], ( inLen - S->Fs_in_kHz ) * sizeof( opus_int16 ) ); } /* Copy to delay buffer */ silk_memcpy( S->delayBuf, &in[ inLen - S->inputDelay ], S->inputDelay * sizeof( opus_int16 ) ); return 0; }