diff options
Diffstat (limited to 'lib/rbcodec/codecs/libopus/silk/LPC_fit.c')
-rw-r--r-- | lib/rbcodec/codecs/libopus/silk/LPC_fit.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/lib/rbcodec/codecs/libopus/silk/LPC_fit.c b/lib/rbcodec/codecs/libopus/silk/LPC_fit.c new file mode 100644 index 0000000000..cdea4f3abc --- /dev/null +++ b/lib/rbcodec/codecs/libopus/silk/LPC_fit.c | |||
@@ -0,0 +1,81 @@ | |||
1 | /*********************************************************************** | ||
2 | Copyright (c) 2013, Koen Vos. 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 | |||
34 | /* Convert int32 coefficients to int16 coefs and make sure there's no wrap-around */ | ||
35 | void silk_LPC_fit( | ||
36 | opus_int16 *a_QOUT, /* O Output signal */ | ||
37 | opus_int32 *a_QIN, /* I/O Input signal */ | ||
38 | const opus_int QOUT, /* I Input Q domain */ | ||
39 | const opus_int QIN, /* I Input Q domain */ | ||
40 | const opus_int d /* I Filter order */ | ||
41 | ) | ||
42 | { | ||
43 | opus_int i, k, idx = 0; | ||
44 | opus_int32 maxabs, absval, chirp_Q16; | ||
45 | |||
46 | /* Limit the maximum absolute value of the prediction coefficients, so that they'll fit in int16 */ | ||
47 | for( i = 0; i < 10; i++ ) { | ||
48 | /* Find maximum absolute value and its index */ | ||
49 | maxabs = 0; | ||
50 | for( k = 0; k < d; k++ ) { | ||
51 | absval = silk_abs( a_QIN[k] ); | ||
52 | if( absval > maxabs ) { | ||
53 | maxabs = absval; | ||
54 | idx = k; | ||
55 | } | ||
56 | } | ||
57 | maxabs = silk_RSHIFT_ROUND( maxabs, QIN - QOUT ); | ||
58 | |||
59 | if( maxabs > silk_int16_MAX ) { | ||
60 | /* Reduce magnitude of prediction coefficients */ | ||
61 | maxabs = silk_min( maxabs, 163838 ); /* ( silk_int32_MAX >> 14 ) + silk_int16_MAX = 163838 */ | ||
62 | chirp_Q16 = SILK_FIX_CONST( 0.999, 16 ) - silk_DIV32( silk_LSHIFT( maxabs - silk_int16_MAX, 14 ), | ||
63 | silk_RSHIFT32( silk_MUL( maxabs, idx + 1), 2 ) ); | ||
64 | silk_bwexpander_32( a_QIN, d, chirp_Q16 ); | ||
65 | } else { | ||
66 | break; | ||
67 | } | ||
68 | } | ||
69 | |||
70 | if( i == 10 ) { | ||
71 | /* Reached the last iteration, clip the coefficients */ | ||
72 | for( k = 0; k < d; k++ ) { | ||
73 | a_QOUT[ k ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND( a_QIN[ k ], QIN - QOUT ) ); | ||
74 | a_QIN[ k ] = silk_LSHIFT( (opus_int32)a_QOUT[ k ], QIN - QOUT ); | ||
75 | } | ||
76 | } else { | ||
77 | for( k = 0; k < d; k++ ) { | ||
78 | a_QOUT[ k ] = (opus_int16)silk_RSHIFT_ROUND( a_QIN[ k ], QIN - QOUT ); | ||
79 | } | ||
80 | } | ||
81 | } | ||