media/libopus/silk/stereo_find_predictor.c@ac0c01689b40 (annotated)
media/libopus/silk/stereo_find_predictor.c
Thu, 15 Jan 2015 15:59:08 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 15 Jan 2015 15:59:08 +0100
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
- permissions
- -rw-r--r--
Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /*********************************************************************** |
| michael@0 | 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| michael@0 | 3 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 4 | modification, are permitted provided that the following conditions |
| michael@0 | 5 | are met: |
| michael@0 | 6 | - Redistributions of source code must retain the above copyright notice, |
| michael@0 | 7 | this list of conditions and the following disclaimer. |
| michael@0 | 8 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 9 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 10 | documentation and/or other materials provided with the distribution. |
| michael@0 | 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| michael@0 | 12 | names of specific contributors, may be used to endorse or promote |
| michael@0 | 13 | products derived from this software without specific prior written |
| michael@0 | 14 | permission. |
| michael@0 | 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| michael@0 | 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| michael@0 | 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| michael@0 | 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| michael@0 | 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| michael@0 | 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| michael@0 | 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| michael@0 | 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| michael@0 | 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| michael@0 | 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| michael@0 | 25 | POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 26 | ***********************************************************************/ |
| michael@0 | 27 | |
| michael@0 | 28 | #ifdef HAVE_CONFIG_H |
| michael@0 | 29 | #include "config.h" |
| michael@0 | 30 | #endif |
| michael@0 | 31 | |
| michael@0 | 32 | #include "main.h" |
| michael@0 | 33 | |
| michael@0 | 34 | /* Find least-squares prediction gain for one signal based on another and quantize it */ |
| michael@0 | 35 | opus_int32 silk_stereo_find_predictor( /* O Returns predictor in Q13 */ |
| michael@0 | 36 | opus_int32 *ratio_Q14, /* O Ratio of residual and mid energies */ |
| michael@0 | 37 | const opus_int16 x[], /* I Basis signal */ |
| michael@0 | 38 | const opus_int16 y[], /* I Target signal */ |
| michael@0 | 39 | opus_int32 mid_res_amp_Q0[], /* I/O Smoothed mid, residual norms */ |
| michael@0 | 40 | opus_int length, /* I Number of samples */ |
| michael@0 | 41 | opus_int smooth_coef_Q16 /* I Smoothing coefficient */ |
| michael@0 | 42 | ) |
| michael@0 | 43 | { |
| michael@0 | 44 | opus_int scale, scale1, scale2; |
| michael@0 | 45 | opus_int32 nrgx, nrgy, corr, pred_Q13, pred2_Q10; |
| michael@0 | 46 | |
| michael@0 | 47 | /* Find predictor */ |
| michael@0 | 48 | silk_sum_sqr_shift( &nrgx, &scale1, x, length ); |
| michael@0 | 49 | silk_sum_sqr_shift( &nrgy, &scale2, y, length ); |
| michael@0 | 50 | scale = silk_max_int( scale1, scale2 ); |
| michael@0 | 51 | scale = scale + ( scale & 1 ); /* make even */ |
| michael@0 | 52 | nrgy = silk_RSHIFT32( nrgy, scale - scale2 ); |
| michael@0 | 53 | nrgx = silk_RSHIFT32( nrgx, scale - scale1 ); |
| michael@0 | 54 | nrgx = silk_max_int( nrgx, 1 ); |
| michael@0 | 55 | corr = silk_inner_prod_aligned_scale( x, y, scale, length ); |
| michael@0 | 56 | pred_Q13 = silk_DIV32_varQ( corr, nrgx, 13 ); |
| michael@0 | 57 | pred_Q13 = silk_LIMIT( pred_Q13, -(1 << 14), 1 << 14 ); |
| michael@0 | 58 | pred2_Q10 = silk_SMULWB( pred_Q13, pred_Q13 ); |
| michael@0 | 59 | |
| michael@0 | 60 | /* Faster update for signals with large prediction parameters */ |
| michael@0 | 61 | smooth_coef_Q16 = (opus_int)silk_max_int( smooth_coef_Q16, silk_abs( pred2_Q10 ) ); |
| michael@0 | 62 | |
| michael@0 | 63 | /* Smoothed mid and residual norms */ |
| michael@0 | 64 | silk_assert( smooth_coef_Q16 < 32768 ); |
| michael@0 | 65 | scale = silk_RSHIFT( scale, 1 ); |
| michael@0 | 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 ], |
| michael@0 | 67 | smooth_coef_Q16 ); |
| michael@0 | 68 | /* Residual energy = nrgy - 2 * pred * corr + pred^2 * nrgx */ |
| michael@0 | 69 | nrgy = silk_SUB_LSHIFT32( nrgy, silk_SMULWB( corr, pred_Q13 ), 3 + 1 ); |
| michael@0 | 70 | nrgy = silk_ADD_LSHIFT32( nrgy, silk_SMULWB( nrgx, pred2_Q10 ), 6 ); |
| michael@0 | 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 ], |
| michael@0 | 72 | smooth_coef_Q16 ); |
| michael@0 | 73 | |
| michael@0 | 74 | /* Ratio of smoothed residual and mid norms */ |
| michael@0 | 75 | *ratio_Q14 = silk_DIV32_varQ( mid_res_amp_Q0[ 1 ], silk_max( mid_res_amp_Q0[ 0 ], 1 ), 14 ); |
| michael@0 | 76 | *ratio_Q14 = silk_LIMIT( *ratio_Q14, 0, 32767 ); |
| michael@0 | 77 | |
| michael@0 | 78 | return pred_Q13; |
| michael@0 | 79 | } |
