GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/mpegaudiodecheader.c Lines: 67 68 98.5 %
Date: 2019-11-20 04:07:19 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/common.h"
28
29
#include "avcodec.h"
30
#include "internal.h"
31
#include "mpegaudio.h"
32
#include "mpegaudiodata.h"
33
#include "mpegaudiodecheader.h"
34
35
36
120737695
int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header)
37
{
38
    int sample_rate, frame_size, mpeg25, padding;
39
    int sample_rate_index, bitrate_index;
40
    int ret;
41
42
120737695
    ret = ff_mpa_check_header(header);
43
120737695
    if (ret < 0)
44
120646977
        return ret;
45
46
90718
    if (header & (1<<20)) {
47
80424
        s->lsf = (header & (1<<19)) ? 0 : 1;
48
80424
        mpeg25 = 0;
49
    } else {
50
10294
        s->lsf = 1;
51
10294
        mpeg25 = 1;
52
    }
53
54
90718
    s->layer = 4 - ((header >> 17) & 3);
55
    /* extract frequency */
56
90718
    sample_rate_index = (header >> 10) & 3;
57
90718
    if (sample_rate_index >= FF_ARRAY_ELEMS(avpriv_mpa_freq_tab))
58
        sample_rate_index = 0;
59
90718
    sample_rate = avpriv_mpa_freq_tab[sample_rate_index] >> (s->lsf + mpeg25);
60
90718
    sample_rate_index += 3 * (s->lsf + mpeg25);
61
90718
    s->sample_rate_index = sample_rate_index;
62
90718
    s->error_protection = ((header >> 16) & 1) ^ 1;
63
90718
    s->sample_rate = sample_rate;
64
65
90718
    bitrate_index = (header >> 12) & 0xf;
66
90718
    padding = (header >> 9) & 1;
67
    //extension = (header >> 8) & 1;
68
90718
    s->mode = (header >> 6) & 3;
69
90718
    s->mode_ext = (header >> 4) & 3;
70
    //copyright = (header >> 3) & 1;
71
    //original = (header >> 2) & 1;
72
    //emphasis = header & 3;
73
74
90718
    if (s->mode == MPA_MONO)
75
42709
        s->nb_channels = 1;
76
    else
77
48009
        s->nb_channels = 2;
78
79
90718
    if (bitrate_index != 0) {
80
55887
        frame_size = avpriv_mpa_bitrate_tab[s->lsf][s->layer - 1][bitrate_index];
81
55887
        s->bit_rate = frame_size * 1000;
82
55887
        switch(s->layer) {
83
18828
        case 1:
84
18828
            frame_size = (frame_size * 12000) / sample_rate;
85
18828
            frame_size = (frame_size + padding) * 4;
86
18828
            break;
87
22008
        case 2:
88
22008
            frame_size = (frame_size * 144000) / sample_rate;
89
22008
            frame_size += padding;
90
22008
            break;
91
15051
        default:
92
        case 3:
93
15051
            frame_size = (frame_size * 144000) / (sample_rate << s->lsf);
94
15051
            frame_size += padding;
95
15051
            break;
96
        }
97
55887
        s->frame_size = frame_size;
98
    } else {
99
        /* if no frame size computed, signal it */
100
34831
        return 1;
101
    }
102
103
#if defined(DEBUG)
104
    ff_dlog(NULL, "layer%d, %d Hz, %d kbits/s, ",
105
           s->layer, s->sample_rate, s->bit_rate);
106
    if (s->nb_channels == 2) {
107
        if (s->layer == 3) {
108
            if (s->mode_ext & MODE_EXT_MS_STEREO)
109
                ff_dlog(NULL, "ms-");
110
            if (s->mode_ext & MODE_EXT_I_STEREO)
111
                ff_dlog(NULL, "i-");
112
        }
113
        ff_dlog(NULL, "stereo");
114
    } else {
115
        ff_dlog(NULL, "mono");
116
    }
117
    ff_dlog(NULL, "\n");
118
#endif
119
55887
    return 0;
120
}
121
122
199178
int ff_mpa_decode_header(uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bit_rate, enum AVCodecID *codec_id)
123
{
124
199178
    MPADecodeHeader s1, *s = &s1;
125
126
199178
    if (avpriv_mpegaudio_decode_header(s, head) != 0) {
127
182948
        return -1;
128
    }
129
130
16230
    switch(s->layer) {
131
3
    case 1:
132
3
        *codec_id = AV_CODEC_ID_MP1;
133
3
        *frame_size = 384;
134
3
        break;
135
10045
    case 2:
136
10045
        *codec_id = AV_CODEC_ID_MP2;
137
10045
        *frame_size = 1152;
138
10045
        break;
139
6182
    default:
140
    case 3:
141
6182
        if (*codec_id != AV_CODEC_ID_MP3ADU)
142
6182
            *codec_id = AV_CODEC_ID_MP3;
143
6182
        if (s->lsf)
144
237
            *frame_size = 576;
145
        else
146
5945
            *frame_size = 1152;
147
6182
        break;
148
    }
149
150
16230
    *sample_rate = s->sample_rate;
151
16230
    *channels = s->nb_channels;
152
16230
    *bit_rate = s->bit_rate;
153
16230
    return s->frame_size;
154
}