| /*********************************************************************** |
| 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, |
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| ***********************************************************************/ |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include "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 */ |
| silk_memcpy( x1, state->sMid, 2 * sizeof( opus_int16 ) ); |
| silk_memcpy( x2, state->sSide, 2 * sizeof( opus_int16 ) ); |
| silk_memcpy( state->sMid, &x1[ frame_length ], 2 * sizeof( opus_int16 ) ); |
| silk_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 = silk_DIV32_16( 1 << 16, STEREO_INTERP_LEN_MS * fs_kHz ); |
| delta0_Q13 = silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 0 ] - state->pred_prev_Q13[ 0 ], denom_Q16 ), 16 ); |
| delta1_Q13 = silk_RSHIFT_ROUND( silk_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 = silk_LSHIFT( silk_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */ |
| sum = silk_SMLAWB( silk_LSHIFT( ( opus_int32 )x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */ |
| sum = silk_SMLAWB( sum, silk_LSHIFT( ( opus_int32 )x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */ |
| x2[ n + 1 ] = (opus_int16)silk_SAT16( silk_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 = silk_LSHIFT( silk_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */ |
| sum = silk_SMLAWB( silk_LSHIFT( ( opus_int32 )x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */ |
| sum = silk_SMLAWB( sum, silk_LSHIFT( ( opus_int32 )x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */ |
| x2[ n + 1 ] = (opus_int16)silk_SAT16( silk_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)silk_SAT16( sum ); |
| x2[ n + 1 ] = (opus_int16)silk_SAT16( diff ); |
| } |
| } |