75 lines
3.9 KiB
C
75 lines
3.9 KiB
C
/***********************************************************************
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Copyright (c) 2006-2010, 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, (subject to the limitations in the disclaimer below)
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are permitted provided that the following conditions 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 Skype Limited, nor the names of specific
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contributors, may be used to endorse or promote products derived from
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this software without specific prior written permission.
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NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED
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BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
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BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
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ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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/* *
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* File Name: SKP_Silk_resample_2_3.c *
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* *
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* Resamples by a factor 2/3 *
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* *
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* Copyright 2008 (c), Skype Limited *
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* All rights reserved. *
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* *
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* Date: 081113 *
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* */
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#include "SKP_Silk_SigProc_FIX.h"
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#define OUT_SUBFR_LEN 80
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/* Resamples by a factor 2/3 */
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void SKP_Silk_resample_2_3(
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SKP_int16 *out, /* O: Fs_low signal [inLen * 2/3] */
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SKP_int32 *S, /* I/O: State vector [7+4] */
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const SKP_int16 *in, /* I: Fs_high signal [inLen] */
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const SKP_int inLen /* I: Input length, must be a multiple of 3 */
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)
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{
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SKP_int outLen, LSubFrameIn, LSubFrameOut;
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SKP_int16 outH[ 3 * OUT_SUBFR_LEN ];
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SKP_int32 scratch[ ( 9 * OUT_SUBFR_LEN ) / 2 ];
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/* Check that input length is multiple of 3 */
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SKP_assert( inLen % 3 == 0 );
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outLen = SKP_DIV32_16( SKP_LSHIFT( inLen, 1 ), 3 );
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while( outLen > 0 ) {
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LSubFrameOut = SKP_min_int( OUT_SUBFR_LEN, outLen );
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LSubFrameIn = SKP_SMULWB( 98304, LSubFrameOut ); /* 98304_Q16 = 3/2_Q0 */
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/* Upsample by a factor 2 */
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/* Scratch size needs to be: 3 * LSubFrameIn * sizeof( SKP_int32 ) */
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SKP_Silk_resample_2_1_coarse( in, &S[ 0 ], outH, scratch, LSubFrameIn );
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/* Downsample by a factor 3 */
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SKP_Silk_resample_1_3( out, &S[ 4 ], outH, SKP_LSHIFT( LSubFrameIn, 1 ) );
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in += LSubFrameIn;
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out += LSubFrameOut;
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outLen -= LSubFrameOut;
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}
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}
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