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-rw-r--r--media/libopus/silk/stereo_MS_to_LR.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/media/libopus/silk/stereo_MS_to_LR.c b/media/libopus/silk/stereo_MS_to_LR.c
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+/***********************************************************************
+Copyright (c) 2006-2011, Skype Limited. All rights reserved.
+Redistribution and use in source and binary forms, with or without
+modification, 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 Internet Society, IETF or IETF Trust, nor the
+names of specific contributors, may be used to endorse or promote
+products derived from this software without specific prior written
+permission.
+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 "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( (opus_int32)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 );
+ }
+}