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73 lines
3.3 KiB
73 lines
3.3 KiB
/*********************************************************************** |
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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 "main.h" |
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/* Quantize mid/side predictors */ |
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void silk_stereo_quant_pred( |
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opus_int32 pred_Q13[], /* I/O Predictors (out: quantized) */ |
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opus_int8 ix[ 2 ][ 3 ] /* O Quantization indices */ |
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) |
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{ |
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opus_int i, j, n; |
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opus_int32 low_Q13, step_Q13, lvl_Q13, err_min_Q13, err_Q13, quant_pred_Q13 = 0; |
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/* Quantize */ |
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for( n = 0; n < 2; n++ ) { |
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/* Brute-force search over quantization levels */ |
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err_min_Q13 = silk_int32_MAX; |
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for( i = 0; i < STEREO_QUANT_TAB_SIZE - 1; i++ ) { |
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low_Q13 = silk_stereo_pred_quant_Q13[ i ]; |
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step_Q13 = silk_SMULWB( silk_stereo_pred_quant_Q13[ i + 1 ] - low_Q13, |
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SILK_FIX_CONST( 0.5 / STEREO_QUANT_SUB_STEPS, 16 ) ); |
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for( j = 0; j < STEREO_QUANT_SUB_STEPS; j++ ) { |
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lvl_Q13 = silk_SMLABB( low_Q13, step_Q13, 2 * j + 1 ); |
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err_Q13 = silk_abs( pred_Q13[ n ] - lvl_Q13 ); |
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if( err_Q13 < err_min_Q13 ) { |
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err_min_Q13 = err_Q13; |
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quant_pred_Q13 = lvl_Q13; |
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ix[ n ][ 0 ] = i; |
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ix[ n ][ 1 ] = j; |
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} else { |
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/* Error increasing, so we're past the optimum */ |
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goto done; |
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} |
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} |
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} |
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done: |
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ix[ n ][ 2 ] = silk_DIV32_16( ix[ n ][ 0 ], 3 ); |
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ix[ n ][ 0 ] -= ix[ n ][ 2 ] * 3; |
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pred_Q13[ n ] = quant_pred_Q13; |
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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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