70 lines
3.3 KiB
C
70 lines
3.3 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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#include "opus/opus_config.h"
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#include "opus/silk/main.h"
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/* Decode mid/side predictors */
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void silk_stereo_decode_pred(
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ec_dec *psRangeDec, /* I/O Compressor data structure */
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opus_int32 pred_Q13[] /* O Predictors */
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)
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{
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opus_int n, ix[ 2 ][ 3 ];
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opus_int32 low_Q13, step_Q13;
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/* Entropy decoding */
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n = ec_dec_icdf( psRangeDec, silk_stereo_pred_joint_iCDF, 8 );
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ix[ 0 ][ 2 ] = silk_DIV32_16( n, 5 );
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ix[ 1 ][ 2 ] = n - 5 * ix[ 0 ][ 2 ];
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for( n = 0; n < 2; n++ ) {
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ix[ n ][ 0 ] = ec_dec_icdf( psRangeDec, silk_uniform3_iCDF, 8 );
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ix[ n ][ 1 ] = ec_dec_icdf( psRangeDec, silk_uniform5_iCDF, 8 );
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}
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/* Dequantize */
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for( n = 0; n < 2; n++ ) {
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ix[ n ][ 0 ] += 3 * ix[ n ][ 2 ];
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low_Q13 = silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] ];
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step_Q13 = silk_SMULWB( silk_stereo_pred_quant_Q13[ ix[ n ][ 0 ] + 1 ] - low_Q13,
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SILK_FIX_CONST( 0.5 / STEREO_QUANT_SUB_STEPS, 16 ) );
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pred_Q13[ n ] = silk_SMLABB( low_Q13, step_Q13, 2 * ix[ n ][ 1 ] + 1 );
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}
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/* Subtract second from first predictor (helps when actually applying these) */
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pred_Q13[ 0 ] -= pred_Q13[ 1 ];
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}
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/* Decode mid-only flag */
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void silk_stereo_decode_mid_only(
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ec_dec *psRangeDec, /* I/O Compressor data structure */
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opus_int *decode_only_mid /* O Flag that only mid channel has been coded */
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)
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{
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/* Decode flag that only mid channel is coded */
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*decode_only_mid = ec_dec_icdf( psRangeDec, silk_stereo_only_code_mid_iCDF, 8 );
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}
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