103 lines
4.7 KiB
C
103 lines
4.7 KiB
C
/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "SigProc_FIX.h"
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#include "resampler_private.h"
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#include "stack_alloc.h"
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#define ORDER_FIR 4
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/* Downsample by a factor 2/3, low quality */
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void silk_resampler_down2_3(
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opus_int32 *S, /* I/O State vector [ 6 ] */
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opus_int16 *out, /* O Output signal [ floor(2*inLen/3) ] */
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const opus_int16 *in, /* I Input signal [ inLen ] */
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opus_int32 inLen /* I Number of input samples */
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)
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{
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opus_int32 nSamplesIn, counter, res_Q6;
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VARDECL( opus_int32, buf );
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opus_int32 *buf_ptr;
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SAVE_STACK;
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ALLOC( buf, RESAMPLER_MAX_BATCH_SIZE_IN + ORDER_FIR, opus_int32 );
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/* Copy buffered samples to start of buffer */
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silk_memcpy( buf, S, ORDER_FIR * sizeof( opus_int32 ) );
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/* Iterate over blocks of frameSizeIn input samples */
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while( 1 ) {
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nSamplesIn = silk_min( inLen, RESAMPLER_MAX_BATCH_SIZE_IN );
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/* Second-order AR filter (output in Q8) */
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silk_resampler_private_AR2( &S[ ORDER_FIR ], &buf[ ORDER_FIR ], in,
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silk_Resampler_2_3_COEFS_LQ, nSamplesIn );
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/* Interpolate filtered signal */
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buf_ptr = buf;
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counter = nSamplesIn;
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while( counter > 2 ) {
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/* Inner product */
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res_Q6 = silk_SMULWB( buf_ptr[ 0 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] );
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res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] );
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res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] );
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res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] );
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/* Scale down, saturate and store in output array */
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*out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) );
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res_Q6 = silk_SMULWB( buf_ptr[ 1 ], silk_Resampler_2_3_COEFS_LQ[ 4 ] );
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res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 2 ], silk_Resampler_2_3_COEFS_LQ[ 5 ] );
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res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 3 ], silk_Resampler_2_3_COEFS_LQ[ 3 ] );
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res_Q6 = silk_SMLAWB( res_Q6, buf_ptr[ 4 ], silk_Resampler_2_3_COEFS_LQ[ 2 ] );
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/* Scale down, saturate and store in output array */
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*out++ = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( res_Q6, 6 ) );
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buf_ptr += 3;
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counter -= 3;
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}
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in += nSamplesIn;
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inLen -= nSamplesIn;
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if( inLen > 0 ) {
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/* More iterations to do; copy last part of filtered signal to beginning of buffer */
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silk_memcpy( buf, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) );
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} else {
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break;
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}
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}
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/* Copy last part of filtered signal to the state for the next call */
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silk_memcpy( S, &buf[ nSamplesIn ], ORDER_FIR * sizeof( opus_int32 ) );
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RESTORE_STACK;
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}
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