Add copy of opus library in deps/third_party.

opus/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, are permitted provided that the following conditions
+are met:
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+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
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+- 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
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+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 );
+    }
+}