FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/pcm_tablegen.h
Date: 2021-09-23 20:34:37
Exec Total Coverage
Lines: 33 39 84.6%
Branches: 12 14 85.7%

Line Branch Exec Source
1 /*
2 * Header file for hardcoded PCM tables
3 *
4 * Copyright (c) 2010 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #ifndef AVCODEC_PCM_TABLEGEN_H
24 #define AVCODEC_PCM_TABLEGEN_H
25
26 #include <stdint.h>
27 #include "libavutil/attributes.h"
28
29 /* from g711.c by SUN microsystems (unrestricted use) */
30
31 #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
32 #define QUANT_MASK (0xf) /* Quantization field mask. */
33 #define NSEGS (8) /* Number of A-law segments. */
34 #define SEG_SHIFT (4) /* Left shift for segment number. */
35 #define SEG_MASK (0x70) /* Segment field mask. */
36
37 #define BIAS (0x84) /* Bias for linear code. */
38
39 #define VIDC_SIGN_BIT (1)
40 #define VIDC_QUANT_MASK (0x1E)
41 #define VIDC_QUANT_SHIFT (1)
42 #define VIDC_SEG_SHIFT (5)
43 #define VIDC_SEG_MASK (0xE0)
44
45 /* alaw2linear() - Convert an A-law value to 16-bit linear PCM */
46 7668 static av_cold int alaw2linear(unsigned char a_val)
47 {
48 int t;
49 int seg;
50
51 7668 a_val ^= 0x55;
52
53 7668 t = a_val & QUANT_MASK;
54 7668 seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
55
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7668 if(seg) t= (t + t + 1 + 32) << (seg + 2);
56 954 else t= (t + t + 1 ) << 3;
57
58
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7668 return (a_val & SIGN_BIT) ? t : -t;
59 }
60
61 4092 static av_cold int ulaw2linear(unsigned char u_val)
62 {
63 int t;
64
65 /* Complement to obtain normal u-law value. */
66 4092 u_val = ~u_val;
67
68 /*
69 * Extract and bias the quantization bits. Then
70 * shift up by the segment number and subtract out the bias.
71 */
72 4092 t = ((u_val & QUANT_MASK) << 3) + BIAS;
73 4092 t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
74
75
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4092 return (u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS);
76 }
77
78 static av_cold int vidc2linear(unsigned char u_val)
79 {
80 int t;
81
82 /*
83 * Extract and bias the quantization bits. Then
84 * shift up by the segment number and subtract out the bias.
85 */
86 t = (((u_val & VIDC_QUANT_MASK) >> VIDC_QUANT_SHIFT) << 3) + BIAS;
87 t <<= ((unsigned)u_val & VIDC_SEG_MASK) >> VIDC_SEG_SHIFT;
88
89 return (u_val & VIDC_SIGN_BIT) ? (BIAS - t) : (t - BIAS);
90 }
91
92 #if CONFIG_HARDCODED_TABLES
93 #define pcm_alaw_tableinit()
94 #define pcm_ulaw_tableinit()
95 #define pcm_vidc_tableinit()
96 #include "libavcodec/pcm_tables.h"
97 #else
98 /* 16384 entries per table */
99 static uint8_t linear_to_alaw[16384];
100 static uint8_t linear_to_ulaw[16384];
101 static uint8_t linear_to_vidc[16384];
102
103 8 static av_cold void build_xlaw_table(uint8_t *linear_to_xlaw,
104 int (*xlaw2linear)(unsigned char),
105 int mask)
106 {
107 int i, j, v, v1, v2;
108
109 8 j = 1;
110 8 linear_to_xlaw[8192] = mask;
111
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1024 for(i=0;i<127;i++) {
112 1016 v1 = xlaw2linear(i ^ mask);
113 1016 v2 = xlaw2linear((i + 1) ^ mask);
114 1016 v = (v1 + v2 + 4) >> 3;
115
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64430 for(;j<v;j+=1) {
116 63414 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
117 63414 linear_to_xlaw[8192 + j] = (i ^ mask);
118 }
119 }
120
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2122 for(;j<8192;j++) {
121 2114 linear_to_xlaw[8192 - j] = (127 ^ (mask ^ 0x80));
122 2114 linear_to_xlaw[8192 + j] = (127 ^ mask);
123 }
124 8 linear_to_xlaw[0] = linear_to_xlaw[1];
125 8 }
126
127 6 static void pcm_alaw_tableinit(void)
128 {
129 6 build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
130 6 }
131
132 2 static void pcm_ulaw_tableinit(void)
133 {
134 2 build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
135 2 }
136
137 static void pcm_vidc_tableinit(void)
138 {
139 build_xlaw_table(linear_to_vidc, vidc2linear, 0xff);
140 }
141 #endif /* CONFIG_HARDCODED_TABLES */
142
143 #endif /* AVCODEC_PCM_TABLEGEN_H */
144