ref: 09767575a5b12f2491b257d3f58157a4139f0296
dir: /silk/silk_stereo_MS_to_LR.c/
/*********************************************************************** Copyright (c) 2006-2011, Skype Limited. All rights reserved. Redistribution and use in source and binary forms, with or without modification, (subject to the limitations in the disclaimer below) 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 Skype Limited, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission. NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED BY THIS LICENSE. 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 #include "silk_main.h" /* Convert adaptive Mid/Side representation to Left/Right stereo signal */ void silk_stereo_MS_to_LR( stereo_dec_state *state, /* I/O State */ opus_int16 x1[], /* I/O Left input signal, becomes mid signal */ opus_int16 x2[], /* I/O Right input signal, becomes side signal */ const opus_int32 pred_Q13[], /* I Predictors */ opus_int fs_kHz, /* I Samples rate (kHz) */ opus_int frame_length /* I Number of samples */ ) { opus_int n, denom_Q16, delta0_Q13, delta1_Q13; opus_int32 sum, diff, pred0_Q13, pred1_Q13; /* Buffering */ SKP_memcpy( x1, state->sMid, 2 * sizeof( opus_int16 ) ); SKP_memcpy( x2, state->sSide, 2 * sizeof( opus_int16 ) ); SKP_memcpy( state->sMid, &x1[ frame_length ], 2 * sizeof( opus_int16 ) ); SKP_memcpy( state->sSide, &x2[ frame_length ], 2 * sizeof( opus_int16 ) ); /* Interpolate predictors and add prediction to side channel */ pred0_Q13 = state->pred_prev_Q13[ 0 ]; pred1_Q13 = state->pred_prev_Q13[ 1 ]; denom_Q16 = SKP_DIV32_16( 1 << 16, STEREO_INTERP_LEN_MS * fs_kHz ); delta0_Q13 = SKP_RSHIFT_ROUND( SKP_SMULBB( pred_Q13[ 0 ] - state->pred_prev_Q13[ 0 ], denom_Q16 ), 16 ); delta1_Q13 = SKP_RSHIFT_ROUND( SKP_SMULBB( pred_Q13[ 1 ] - state->pred_prev_Q13[ 1 ], denom_Q16 ), 16 ); for( n = 0; n < STEREO_INTERP_LEN_MS * fs_kHz; n++ ) { pred0_Q13 += delta0_Q13; pred1_Q13 += delta1_Q13; sum = SKP_LSHIFT( SKP_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */ sum = SKP_SMLAWB( SKP_LSHIFT( ( opus_int32 )x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */ sum = SKP_SMLAWB( sum, SKP_LSHIFT( ( opus_int32 )x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */ x2[ n + 1 ] = (opus_int16)SKP_SAT16( SKP_RSHIFT_ROUND( sum, 8 ) ); } pred0_Q13 = pred_Q13[ 0 ]; pred1_Q13 = pred_Q13[ 1 ]; for( n = STEREO_INTERP_LEN_MS * fs_kHz; n < frame_length; n++ ) { sum = SKP_LSHIFT( SKP_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */ sum = SKP_SMLAWB( SKP_LSHIFT( ( opus_int32 )x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */ sum = SKP_SMLAWB( sum, SKP_LSHIFT( ( opus_int32 )x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */ x2[ n + 1 ] = (opus_int16)SKP_SAT16( SKP_RSHIFT_ROUND( sum, 8 ) ); } state->pred_prev_Q13[ 0 ] = pred_Q13[ 0 ]; state->pred_prev_Q13[ 1 ] = pred_Q13[ 1 ]; /* Convert to left/right signals */ for( n = 0; n < frame_length; n++ ) { sum = x1[ n + 1 ] + (opus_int32)x2[ n + 1 ]; diff = x1[ n + 1 ] - (opus_int32)x2[ n + 1 ]; x1[ n + 1 ] = (opus_int16)SKP_SAT16( sum ); x2[ n + 1 ] = (opus_int16)SKP_SAT16( diff ); } }