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comparison: media/libopus/silk/stereo_find_predictor.c
media/libopus/silk/stereo_find_predictor.c
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- TOR_BUG_9701
- changeset 15
- b8a032363ba2
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| -1:000000000000 | 0:44452e3e51ae |
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| 1 /*********************************************************************** | |
| 2 Copyright (c) 2006-2011, Skype Limited. All rights reserved. | |
| 3 Redistribution and use in source and binary forms, with or without | |
| 4 modification, are permitted provided that the following conditions | |
| 5 are met: | |
| 6 - Redistributions of source code must retain the above copyright notice, | |
| 7 this list of conditions and the following disclaimer. | |
| 8 - Redistributions in binary form must reproduce the above copyright | |
| 9 notice, this list of conditions and the following disclaimer in the | |
| 10 documentation and/or other materials provided with the distribution. | |
| 11 - Neither the name of Internet Society, IETF or IETF Trust, nor the | |
| 12 names of specific contributors, may be used to endorse or promote | |
| 13 products derived from this software without specific prior written | |
| 14 permission. | |
| 15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 16 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 17 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 18 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 19 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 20 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 21 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 22 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 23 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 24 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 25 POSSIBILITY OF SUCH DAMAGE. | |
| 26 ***********************************************************************/ | |
| 27 | |
| 28 #ifdef HAVE_CONFIG_H | |
| 29 #include "config.h" | |
| 30 #endif | |
| 31 | |
| 32 #include "main.h" | |
| 33 | |
| 34 /* Find least-squares prediction gain for one signal based on another and quantize it */ | |
| 35 opus_int32 silk_stereo_find_predictor( /* O Returns predictor in Q13 */ | |
| 36 opus_int32 *ratio_Q14, /* O Ratio of residual and mid energies */ | |
| 37 const opus_int16 x[], /* I Basis signal */ | |
| 38 const opus_int16 y[], /* I Target signal */ | |
| 39 opus_int32 mid_res_amp_Q0[], /* I/O Smoothed mid, residual norms */ | |
| 40 opus_int length, /* I Number of samples */ | |
| 41 opus_int smooth_coef_Q16 /* I Smoothing coefficient */ | |
| 42 ) | |
| 43 { | |
| 44 opus_int scale, scale1, scale2; | |
| 45 opus_int32 nrgx, nrgy, corr, pred_Q13, pred2_Q10; | |
| 46 | |
| 47 /* Find predictor */ | |
| 48 silk_sum_sqr_shift( &nrgx, &scale1, x, length ); | |
| 49 silk_sum_sqr_shift( &nrgy, &scale2, y, length ); | |
| 50 scale = silk_max_int( scale1, scale2 ); | |
| 51 scale = scale + ( scale & 1 ); /* make even */ | |
| 52 nrgy = silk_RSHIFT32( nrgy, scale - scale2 ); | |
| 53 nrgx = silk_RSHIFT32( nrgx, scale - scale1 ); | |
| 54 nrgx = silk_max_int( nrgx, 1 ); | |
| 55 corr = silk_inner_prod_aligned_scale( x, y, scale, length ); | |
| 56 pred_Q13 = silk_DIV32_varQ( corr, nrgx, 13 ); | |
| 57 pred_Q13 = silk_LIMIT( pred_Q13, -(1 << 14), 1 << 14 ); | |
| 58 pred2_Q10 = silk_SMULWB( pred_Q13, pred_Q13 ); | |
| 59 | |
| 60 /* Faster update for signals with large prediction parameters */ | |
| 61 smooth_coef_Q16 = (opus_int)silk_max_int( smooth_coef_Q16, silk_abs( pred2_Q10 ) ); | |
| 62 | |
| 63 /* Smoothed mid and residual norms */ | |
| 64 silk_assert( smooth_coef_Q16 < 32768 ); | |
| 65 scale = silk_RSHIFT( scale, 1 ); | |
| 66 mid_res_amp_Q0[ 0 ] = silk_SMLAWB( mid_res_amp_Q0[ 0 ], silk_LSHIFT( silk_SQRT_APPROX( nrgx ), scale ) - mid_res_amp_Q0[ 0 ], | |
| 67 smooth_coef_Q16 ); | |
| 68 /* Residual energy = nrgy - 2 * pred * corr + pred^2 * nrgx */ | |
| 69 nrgy = silk_SUB_LSHIFT32( nrgy, silk_SMULWB( corr, pred_Q13 ), 3 + 1 ); | |
| 70 nrgy = silk_ADD_LSHIFT32( nrgy, silk_SMULWB( nrgx, pred2_Q10 ), 6 ); | |
| 71 mid_res_amp_Q0[ 1 ] = silk_SMLAWB( mid_res_amp_Q0[ 1 ], silk_LSHIFT( silk_SQRT_APPROX( nrgy ), scale ) - mid_res_amp_Q0[ 1 ], | |
| 72 smooth_coef_Q16 ); | |
| 73 | |
| 74 /* Ratio of smoothed residual and mid norms */ | |
| 75 *ratio_Q14 = silk_DIV32_varQ( mid_res_amp_Q0[ 1 ], silk_max( mid_res_amp_Q0[ 0 ], 1 ), 14 ); | |
| 76 *ratio_Q14 = silk_LIMIT( *ratio_Q14, 0, 32767 ); | |
| 77 | |
| 78 return pred_Q13; | |
| 79 } |
