FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/lpc_functions.h
Date: 2025-06-23 20:06:14
Exec Total Coverage
Lines: 27 30 90.0%
Functions: 1 1 100.0%
Branches: 21 26 80.8%

Line Branch Exec Source
1 /*
2 * LPC utility functions
3 * Copyright (c) 2006 Justin Ruggles <justin.ruggles@gmail.com>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #ifndef AVCODEC_LPC_FUNCTIONS_H
23 #define AVCODEC_LPC_FUNCTIONS_H
24
25 #include "libavutil/avassert.h"
26
27 #ifndef LPC_USE_FIXED
28 #define LPC_USE_FIXED 0
29 #endif
30
31 #if LPC_USE_FIXED
32 typedef int LPC_TYPE;
33 typedef unsigned LPC_TYPE_U;
34 #else
35 #ifndef LPC_SRA_R
36 #define LPC_SRA_R(x, y) (x)
37 #define LPC_MUL26(x, y) ((x) * (y))
38 #define LPC_FIXR(x) ((float)(x))
39 #endif
40
41 #ifdef LPC_USE_DOUBLE
42 typedef double LPC_TYPE;
43 typedef double LPC_TYPE_U;
44 #else
45 typedef float LPC_TYPE;
46 typedef float LPC_TYPE_U;
47 #endif
48 #endif // USE_FIXED
49
50 /**
51 * Levinson-Durbin recursion.
52 * Produce LPC coefficients from autocorrelation data.
53 */
54 38280 static inline int compute_lpc_coefs(const LPC_TYPE *autoc, int i, int max_order,
55 LPC_TYPE *lpc, int lpc_stride, int fail,
56 int normalize, LPC_TYPE *err_ptr)
57 {
58 38280 LPC_TYPE err = 0;
59 38280 LPC_TYPE *lpc_last = lpc;
60
61 av_assert2(normalize || !fail);
62
63
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38280 if (normalize) {
64
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29315 if (i == 0)
65 29315 err = *autoc++;
66 else {
67 err = *err_ptr;
68 }
69 }
70
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38280 if (fail && (autoc[max_order - 1] == 0 || err <= 0))
72 4 return -1;
73
74
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650070 for( ; i < max_order; i++) {
75 611794 LPC_TYPE r = LPC_SRA_R(-autoc[i], 5);
76
77
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611794 if (normalize) {
78
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7900749 for(int j = 0; j < i; j++)
79 7348015 r -= lpc_last[j] * autoc[i-j-1];
80
81
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552734 if (err)
82 552734 r /= err;
83 552734 err *= LPC_FIXR(1.0) - (r * r);
84 }
85
86 611794 lpc[i] = r;
87
88
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4549999 for(int j = 0; j < (i + 1) >> 1; j++) {
89 3938205 LPC_TYPE f = lpc_last[ j];
90 3938205 LPC_TYPE b = lpc_last[i-1-j];
91 3938205 lpc[ j] = f + (LPC_TYPE_U)LPC_MUL26(r, b);
92 3938205 lpc[i-1-j] = b + (LPC_TYPE_U)LPC_MUL26(r, f);
93 }
94
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611794 if (fail && err < 0)
96 return -1;
97
98 611794 lpc_last = lpc;
99 611794 lpc += lpc_stride;
100 }
101
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38276 if (err_ptr)
103 *err_ptr = err;
104
105 38276 return 0;
106 }
107
108 #endif /* AVCODEC_LPC_FUNCTIONS_H */
109