FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mpegaudiodecheader.c
Date: 2026-01-16 07:34:38
Exec Total Coverage
Lines: 67 68 98.5%
Functions: 2 2 100.0%
Branches: 20 22 90.9%
Line Branch Exec Source
1 /*
2 * MPEG Audio header decoder
3 * Copyright (c) 2001, 2002 Fabrice Bellard
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 /**
23 * @file
24 * MPEG Audio header decoder.
25 */
26
27 #include "libavutil/macros.h"
28
29 #include "mpegaudio.h"
30 #include "mpegaudiodata.h"
31 #include "mpegaudiodecheader.h"
32
33
34 371537149 int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
35 {
36 int sample_rate, frame_size, mpeg25, padding;
37 int sample_rate_index, bitrate_index;
38 int ret;
39
40 371537149 ret = ff_mpa_check_header(header);
41
2/2
✓ Branch 0 taken 371335083 times.
✓ Branch 1 taken 202066 times.
 371537149 if (ret < 0)
42 371335083 return ret;
43
44
2/2
✓ Branch 0 taken 177832 times.
✓ Branch 1 taken 24234 times.
 202066 if (header & (1<<20)) {
45 177832 s->lsf = (header & (1<<19)) ? 0 : 1;
46 177832 mpeg25 = 0;
47 } else {
48 24234 s->lsf = 1;
49 24234 mpeg25 = 1;
50 }
51
52 202066 s->layer = 4 - ((header >> 17) & 3);
53 /* extract frequency */
54 202066 sample_rate_index = (header >> 10) & 3;
55
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 202066 times.
 202066 if (sample_rate_index >= FF_ARRAY_ELEMS(ff_mpa_freq_tab))
56 ✗ sample_rate_index = 0;
57 202066 sample_rate = ff_mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);
58 202066 sample_rate_index += 3 * (s->lsf + mpeg25);
59 202066 s->sample_rate_index = sample_rate_index;
60 202066 s->error_protection = ((header >> 16) & 1) ^ 1;
61 202066 s->sample_rate = sample_rate;
62
63 202066 bitrate_index = (header >> 12) & 0xf;
64 202066 padding = (header >> 9) & 1;
65 //extension = (header >> 8) & 1;
66 202066 s->mode = (header >> 6) & 3;
67 202066 s->mode_ext = (header >> 4) & 3;
68 //copyright = (header >> 3) & 1;
69 //original = (header >> 2) & 1;
70 //emphasis = header & 3;
71
72
2/2
✓ Branch 0 taken 82991 times.
✓ Branch 1 taken 119075 times.
 202066 if (s->mode == MPA_MONO)
73 82991 s->nb_channels = 1;
74 else
75 119075 s->nb_channels = 2;
76
77
2/2
✓ Branch 0 taken 99805 times.
✓ Branch 1 taken 102261 times.
 202066 if (bitrate_index != 0) {
78 99805 frame_size = ff_mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];
79 99805 s->bit_rate = frame_size * 1000;
80
3/3
✓ Branch 0 taken 45658 times.
✓ Branch 1 taken 28770 times.
✓ Branch 2 taken 25377 times.
 99805 switch(s->layer) {
81 45658 case 1:
82 45658 frame_size = (frame_size * 12000) / sample_rate;
83 45658 frame_size = (frame_size + padding) * 4;
84 45658 break;
85 28770 case 2:
86 28770 frame_size = (frame_size * 144000) / sample_rate;
87 28770 frame_size += padding;
88 28770 break;
89 25377 default:
90 case 3:
91 25377 frame_size = (frame_size * 144000) / (sample_rate << s->lsf);
92 25377 frame_size += padding;
93 25377 break;
94 }
95 99805 s->frame_size = frame_size;
96 } else {
97 /* if no frame size computed, signal it */
98 102261 return 1;
99 }
100
101 #if defined(DEBUG)
102 ff_dlog(NULL, "layer%d, %d Hz, %d kbits/s, ",
103 s->layer, s->sample_rate, s->bit_rate);
104 if (s->nb_channels == 2) {
105 if (s->layer == 3) {
106 if (s->mode_ext & MODE_EXT_MS_STEREO)
107 ff_dlog(NULL, "ms-");
108 if (s->mode_ext & MODE_EXT_I_STEREO)
109 ff_dlog(NULL, "i-");
110 }
111 ff_dlog(NULL, "stereo");
112 } else {
113 ff_dlog(NULL, "mono");
114 }
115 ff_dlog(NULL, "\n");
116 #endif
117 99805 return 0;
118 }
119
120 285692 int ff_mpa_decode_header(uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bit_rate, enum AVCodecID *codec_id)
121 {
122 285692 MPADecodeHeader s1, *s = &s1;
123
124
2/2
✓ Branch 1 taken 267346 times.
✓ Branch 2 taken 18346 times.
 285692 if (avpriv_mpegaudio_decode_header(s, head) != 0) {
125 267346 return -1;
126 }
127
128
3/3
✓ Branch 0 taken 68 times.
✓ Branch 1 taken 10456 times.
✓ Branch 2 taken 7822 times.
 18346 switch(s->layer) {
129 68 case 1:
130 68 *codec_id = AV_CODEC_ID_MP1;
131 68 *frame_size = 384;
132 68 break;
133 10456 case 2:
134 10456 *codec_id = AV_CODEC_ID_MP2;
135 10456 *frame_size = 1152;
136 10456 break;
137 7822 default:
138 case 3:
139
1/2
✓ Branch 0 taken 7822 times.
✗ Branch 1 not taken.
 7822 if (*codec_id != AV_CODEC_ID_MP3ADU)
140 7822 *codec_id = AV_CODEC_ID_MP3;
141
2/2
✓ Branch 0 taken 257 times.
✓ Branch 1 taken 7565 times.
 7822 if (s->lsf)
142 257 *frame_size = 576;
143 else
144 7565 *frame_size = 1152;
145 7822 break;
146 }
147
148 18346 *sample_rate = s->sample_rate;
149 18346 *channels = s->nb_channels;
150 18346 *bit_rate = s->bit_rate;
151 18346 return s->frame_size;
152 }
153