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Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/stereo_find_predictor.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/stereo_find_predictor.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/stereo_find_predictor.c b/lib/rbcodec/codecs/libopus/silk/stereo_find_predictor.c new file mode 100644 index 0000000000..e30e90bddc --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/stereo_find_predictor.c | |||
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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 | } | ||