Add copy of opus library in deps/third_party.
TBR=dannyb@google.com
Review URL: https://codereview.chromium.org/11196031
git-svn-id: svn://svn.chromium.org/chrome/trunk/deps/third_party/opus@162558 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/silk/stereo_find_predictor.c b/silk/stereo_find_predictor.c
new file mode 100644
index 0000000..aec58da
--- /dev/null
+++ b/silk/stereo_find_predictor.c
@@ -0,0 +1,79 @@
+/***********************************************************************
+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"
+
+/* Find least-squares prediction gain for one signal based on another and quantize it */
+opus_int32 silk_stereo_find_predictor( /* O Returns predictor in Q13 */
+ opus_int32 *ratio_Q14, /* O Ratio of residual and mid energies */
+ const opus_int16 x[], /* I Basis signal */
+ const opus_int16 y[], /* I Target signal */
+ opus_int32 mid_res_amp_Q0[], /* I/O Smoothed mid, residual norms */
+ opus_int length, /* I Number of samples */
+ opus_int smooth_coef_Q16 /* I Smoothing coefficient */
+)
+{
+ opus_int scale, scale1, scale2;
+ opus_int32 nrgx, nrgy, corr, pred_Q13, pred2_Q10;
+
+ /* Find predictor */
+ silk_sum_sqr_shift( &nrgx, &scale1, x, length );
+ silk_sum_sqr_shift( &nrgy, &scale2, y, length );
+ scale = silk_max_int( scale1, scale2 );
+ scale = scale + ( scale & 1 ); /* make even */
+ nrgy = silk_RSHIFT32( nrgy, scale - scale2 );
+ nrgx = silk_RSHIFT32( nrgx, scale - scale1 );
+ nrgx = silk_max_int( nrgx, 1 );
+ corr = silk_inner_prod_aligned_scale( x, y, scale, length );
+ pred_Q13 = silk_DIV32_varQ( corr, nrgx, 13 );
+ pred_Q13 = silk_LIMIT( pred_Q13, -(1 << 14), 1 << 14 );
+ pred2_Q10 = silk_SMULWB( pred_Q13, pred_Q13 );
+
+ /* Faster update for signals with large prediction parameters */
+ smooth_coef_Q16 = (opus_int)silk_max_int( smooth_coef_Q16, silk_abs( pred2_Q10 ) );
+
+ /* Smoothed mid and residual norms */
+ silk_assert( smooth_coef_Q16 < 32768 );
+ scale = silk_RSHIFT( scale, 1 );
+ mid_res_amp_Q0[ 0 ] = silk_SMLAWB( mid_res_amp_Q0[ 0 ], silk_LSHIFT( silk_SQRT_APPROX( nrgx ), scale ) - mid_res_amp_Q0[ 0 ],
+ smooth_coef_Q16 );
+ /* Residual energy = nrgy - 2 * pred * corr + pred^2 * nrgx */
+ nrgy = silk_SUB_LSHIFT32( nrgy, silk_SMULWB( corr, pred_Q13 ), 3 + 1 );
+ nrgy = silk_ADD_LSHIFT32( nrgy, silk_SMULWB( nrgx, pred2_Q10 ), 6 );
+ mid_res_amp_Q0[ 1 ] = silk_SMLAWB( mid_res_amp_Q0[ 1 ], silk_LSHIFT( silk_SQRT_APPROX( nrgy ), scale ) - mid_res_amp_Q0[ 1 ],
+ smooth_coef_Q16 );
+
+ /* Ratio of smoothed residual and mid norms */
+ *ratio_Q14 = silk_DIV32_varQ( mid_res_amp_Q0[ 1 ], silk_max( mid_res_amp_Q0[ 0 ], 1 ), 14 );
+ *ratio_Q14 = silk_LIMIT( *ratio_Q14, 0, 32767 );
+
+ return pred_Q13;
+}