diff options
Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/float/LPC_inv_pred_gain_FLP.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/float/LPC_inv_pred_gain_FLP.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/float/LPC_inv_pred_gain_FLP.c b/lib/rbcodec/codecs/libopus/silk/float/LPC_inv_pred_gain_FLP.c new file mode 100644 index 0000000000..2be2122d61 --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/float/LPC_inv_pred_gain_FLP.c | |||
@@ -0,0 +1,73 @@ | |||
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 "SigProc_FIX.h" | ||
33 | #include "SigProc_FLP.h" | ||
34 | #include "define.h" | ||
35 | |||
36 | /* compute inverse of LPC prediction gain, and */ | ||
37 | /* test if LPC coefficients are stable (all poles within unit circle) */ | ||
38 | /* this code is based on silk_a2k_FLP() */ | ||
39 | silk_float silk_LPC_inverse_pred_gain_FLP( /* O return inverse prediction gain, energy domain */ | ||
40 | const silk_float *A, /* I prediction coefficients [order] */ | ||
41 | opus_int32 order /* I prediction order */ | ||
42 | ) | ||
43 | { | ||
44 | opus_int k, n; | ||
45 | double invGain, rc, rc_mult1, rc_mult2, tmp1, tmp2; | ||
46 | silk_float Atmp[ SILK_MAX_ORDER_LPC ]; | ||
47 | |||
48 | silk_memcpy( Atmp, A, order * sizeof(silk_float) ); | ||
49 | |||
50 | invGain = 1.0; | ||
51 | for( k = order - 1; k > 0; k-- ) { | ||
52 | rc = -Atmp[ k ]; | ||
53 | rc_mult1 = 1.0f - rc * rc; | ||
54 | invGain *= rc_mult1; | ||
55 | if( invGain * MAX_PREDICTION_POWER_GAIN < 1.0f ) { | ||
56 | return 0.0f; | ||
57 | } | ||
58 | rc_mult2 = 1.0f / rc_mult1; | ||
59 | for( n = 0; n < (k + 1) >> 1; n++ ) { | ||
60 | tmp1 = Atmp[ n ]; | ||
61 | tmp2 = Atmp[ k - n - 1 ]; | ||
62 | Atmp[ n ] = (silk_float)( ( tmp1 - tmp2 * rc ) * rc_mult2 ); | ||
63 | Atmp[ k - n - 1 ] = (silk_float)( ( tmp2 - tmp1 * rc ) * rc_mult2 ); | ||
64 | } | ||
65 | } | ||
66 | rc = -Atmp[ 0 ]; | ||
67 | rc_mult1 = 1.0f - rc * rc; | ||
68 | invGain *= rc_mult1; | ||
69 | if( invGain * MAX_PREDICTION_POWER_GAIN < 1.0f ) { | ||
70 | return 0.0f; | ||
71 | } | ||
72 | return (silk_float)invGain; | ||
73 | } | ||