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+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, 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 Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+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;
+}