Add copy of opus library in deps/third_party.

opus/silk/stereo_encode_pred.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:
+- 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"
+
+/* Entropy code the mid/side quantization indices */
+void silk_stereo_encode_pred(
+    ec_enc                      *psRangeEnc,                    /* I/O  Compressor data structure                   */
+    opus_int8                   ix[ 2 ][ 3 ]                    /* I    Quantization indices                        */
+)
+{
+    opus_int   n;
+
+    /* Entropy coding */
+    n = 5 * ix[ 0 ][ 2 ] + ix[ 1 ][ 2 ];
+    silk_assert( n < 25 );
+    ec_enc_icdf( psRangeEnc, n, silk_stereo_pred_joint_iCDF, 8 );
+    for( n = 0; n < 2; n++ ) {
+        silk_assert( ix[ n ][ 0 ] < 3 );
+        silk_assert( ix[ n ][ 1 ] < STEREO_QUANT_SUB_STEPS );
+        ec_enc_icdf( psRangeEnc, ix[ n ][ 0 ], silk_uniform3_iCDF, 8 );
+        ec_enc_icdf( psRangeEnc, ix[ n ][ 1 ], silk_uniform5_iCDF, 8 );
+    }
+}
+
+/* Entropy code the mid-only flag */
+void silk_stereo_encode_mid_only(
+    ec_enc                      *psRangeEnc,                    /* I/O  Compressor data structure                   */
+    opus_int8                   mid_only_flag
+)
+{
+    /* Encode flag that only mid channel is coded */
+    ec_enc_icdf( psRangeEnc, mid_only_flag, silk_stereo_only_code_mid_iCDF, 8 );
+}