86 lines
4.8 KiB
C
86 lines
4.8 KiB
C
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/***********************************************************************
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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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/* Convert adaptive Mid/Side representation to Left/Right stereo signal */
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void silk_stereo_MS_to_LR(
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stereo_dec_state *state, /* I/O State */
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opus_int16 x1[], /* I/O Left input signal, becomes mid signal */
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opus_int16 x2[], /* I/O Right input signal, becomes side signal */
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const opus_int32 pred_Q13[], /* I Predictors */
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opus_int fs_kHz, /* I Samples rate (kHz) */
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opus_int frame_length /* I Number of samples */
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)
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{
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opus_int n, denom_Q16, delta0_Q13, delta1_Q13;
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opus_int32 sum, diff, pred0_Q13, pred1_Q13;
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/* Buffering */
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silk_memcpy( x1, state->sMid, 2 * sizeof( opus_int16 ) );
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silk_memcpy( x2, state->sSide, 2 * sizeof( opus_int16 ) );
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silk_memcpy( state->sMid, &x1[ frame_length ], 2 * sizeof( opus_int16 ) );
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silk_memcpy( state->sSide, &x2[ frame_length ], 2 * sizeof( opus_int16 ) );
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/* Interpolate predictors and add prediction to side channel */
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pred0_Q13 = state->pred_prev_Q13[ 0 ];
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pred1_Q13 = state->pred_prev_Q13[ 1 ];
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denom_Q16 = silk_DIV32_16( (opus_int32)1 << 16, STEREO_INTERP_LEN_MS * fs_kHz );
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delta0_Q13 = silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 0 ] - state->pred_prev_Q13[ 0 ], denom_Q16 ), 16 );
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delta1_Q13 = silk_RSHIFT_ROUND( silk_SMULBB( pred_Q13[ 1 ] - state->pred_prev_Q13[ 1 ], denom_Q16 ), 16 );
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for( n = 0; n < STEREO_INTERP_LEN_MS * fs_kHz; n++ ) {
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pred0_Q13 += delta0_Q13;
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pred1_Q13 += delta1_Q13;
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sum = silk_LSHIFT( silk_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */
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sum = silk_SMLAWB( silk_LSHIFT( (opus_int32)x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */
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sum = silk_SMLAWB( sum, silk_LSHIFT( (opus_int32)x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */
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x2[ n + 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( sum, 8 ) );
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}
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pred0_Q13 = pred_Q13[ 0 ];
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pred1_Q13 = pred_Q13[ 1 ];
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for( n = STEREO_INTERP_LEN_MS * fs_kHz; n < frame_length; n++ ) {
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sum = silk_LSHIFT( silk_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */
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sum = silk_SMLAWB( silk_LSHIFT( (opus_int32)x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */
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sum = silk_SMLAWB( sum, silk_LSHIFT( (opus_int32)x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */
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x2[ n + 1 ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( sum, 8 ) );
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}
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state->pred_prev_Q13[ 0 ] = pred_Q13[ 0 ];
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state->pred_prev_Q13[ 1 ] = pred_Q13[ 1 ];
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/* Convert to left/right signals */
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for( n = 0; n < frame_length; n++ ) {
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sum = x1[ n + 1 ] + (opus_int32)x2[ n + 1 ];
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diff = x1[ n + 1 ] - (opus_int32)x2[ n + 1 ];
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x1[ n + 1 ] = (opus_int16)silk_SAT16( sum );
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x2[ n + 1 ] = (opus_int16)silk_SAT16( diff );
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}
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}
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