1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/stereo_find_predictor.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,79 @@
1.4 +/***********************************************************************
1.5 +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
1.6 +Redistribution and use in source and binary forms, with or without
1.7 +modification, are permitted provided that the following conditions
1.8 +are met:
1.9 +- Redistributions of source code must retain the above copyright notice,
1.10 +this list of conditions and the following disclaimer.
1.11 +- Redistributions in binary form must reproduce the above copyright
1.12 +notice, this list of conditions and the following disclaimer in the
1.13 +documentation and/or other materials provided with the distribution.
1.14 +- Neither the name of Internet Society, IETF or IETF Trust, nor the
1.15 +names of specific contributors, may be used to endorse or promote
1.16 +products derived from this software without specific prior written
1.17 +permission.
1.18 +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.19 +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.20 +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.21 +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
1.22 +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.23 +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.24 +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.25 +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.26 +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.27 +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.28 +POSSIBILITY OF SUCH DAMAGE.
1.29 +***********************************************************************/
1.30 +
1.31 +#ifdef HAVE_CONFIG_H
1.32 +#include "config.h"
1.33 +#endif
1.34 +
1.35 +#include "main.h"
1.36 +
1.37 +/* Find least-squares prediction gain for one signal based on another and quantize it */
1.38 +opus_int32 silk_stereo_find_predictor( /* O Returns predictor in Q13 */
1.39 + opus_int32 *ratio_Q14, /* O Ratio of residual and mid energies */
1.40 + const opus_int16 x[], /* I Basis signal */
1.41 + const opus_int16 y[], /* I Target signal */
1.42 + opus_int32 mid_res_amp_Q0[], /* I/O Smoothed mid, residual norms */
1.43 + opus_int length, /* I Number of samples */
1.44 + opus_int smooth_coef_Q16 /* I Smoothing coefficient */
1.45 +)
1.46 +{
1.47 + opus_int scale, scale1, scale2;
1.48 + opus_int32 nrgx, nrgy, corr, pred_Q13, pred2_Q10;
1.49 +
1.50 + /* Find predictor */
1.51 + silk_sum_sqr_shift( &nrgx, &scale1, x, length );
1.52 + silk_sum_sqr_shift( &nrgy, &scale2, y, length );
1.53 + scale = silk_max_int( scale1, scale2 );
1.54 + scale = scale + ( scale & 1 ); /* make even */
1.55 + nrgy = silk_RSHIFT32( nrgy, scale - scale2 );
1.56 + nrgx = silk_RSHIFT32( nrgx, scale - scale1 );
1.57 + nrgx = silk_max_int( nrgx, 1 );
1.58 + corr = silk_inner_prod_aligned_scale( x, y, scale, length );
1.59 + pred_Q13 = silk_DIV32_varQ( corr, nrgx, 13 );
1.60 + pred_Q13 = silk_LIMIT( pred_Q13, -(1 << 14), 1 << 14 );
1.61 + pred2_Q10 = silk_SMULWB( pred_Q13, pred_Q13 );
1.62 +
1.63 + /* Faster update for signals with large prediction parameters */
1.64 + smooth_coef_Q16 = (opus_int)silk_max_int( smooth_coef_Q16, silk_abs( pred2_Q10 ) );
1.65 +
1.66 + /* Smoothed mid and residual norms */
1.67 + silk_assert( smooth_coef_Q16 < 32768 );
1.68 + scale = silk_RSHIFT( scale, 1 );
1.69 + mid_res_amp_Q0[ 0 ] = silk_SMLAWB( mid_res_amp_Q0[ 0 ], silk_LSHIFT( silk_SQRT_APPROX( nrgx ), scale ) - mid_res_amp_Q0[ 0 ],
1.70 + smooth_coef_Q16 );
1.71 + /* Residual energy = nrgy - 2 * pred * corr + pred^2 * nrgx */
1.72 + nrgy = silk_SUB_LSHIFT32( nrgy, silk_SMULWB( corr, pred_Q13 ), 3 + 1 );
1.73 + nrgy = silk_ADD_LSHIFT32( nrgy, silk_SMULWB( nrgx, pred2_Q10 ), 6 );
1.74 + mid_res_amp_Q0[ 1 ] = silk_SMLAWB( mid_res_amp_Q0[ 1 ], silk_LSHIFT( silk_SQRT_APPROX( nrgy ), scale ) - mid_res_amp_Q0[ 1 ],
1.75 + smooth_coef_Q16 );
1.76 +
1.77 + /* Ratio of smoothed residual and mid norms */
1.78 + *ratio_Q14 = silk_DIV32_varQ( mid_res_amp_Q0[ 1 ], silk_max( mid_res_amp_Q0[ 0 ], 1 ), 14 );
1.79 + *ratio_Q14 = silk_LIMIT( *ratio_Q14, 0, 32767 );
1.80 +
1.81 + return pred_Q13;
1.82 +}
