FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/mpegaudiodecheader.h
Date: 2021-09-24 20:55:06
Exec Total Coverage
Lines: 12 12 100.0%
Branches: 10 10 100.0%

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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 #ifndef AVCODEC_MPEGAUDIODECHEADER_H
28 #define AVCODEC_MPEGAUDIODECHEADER_H
29
30 #include <stdint.h>
31 #include "codec_id.h"
32
33 #define MP3_MASK 0xFFFE0CCF
34
35 #define MPA_DECODE_HEADER \
36 int frame_size; \
37 int error_protection; \
38 int layer; \
39 int sample_rate; \
40 int sample_rate_index; /* between 0 and 8 */ \
41 int bit_rate; \
42 int nb_channels; \
43 int mode; \
44 int mode_ext; \
45 int lsf;
46
47 typedef struct MPADecodeHeader {
48 MPA_DECODE_HEADER
49 } MPADecodeHeader;
50
51 /* header decoding. MUST check the header before because no
52 consistency check is done there. Return 1 if free format found and
53 that the frame size must be computed externally */
54 int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header);
55
56 /* useful helper to get MPEG audio stream info. Return -1 if error in
57 header, otherwise the coded frame size in bytes */
58 int ff_mpa_decode_header(uint32_t head, int *sample_rate,
59 int *channels, int *frame_size, int *bitrate, enum AVCodecID *codec_id);
60
61 /* fast header check for resync */
62 124734777 static inline int ff_mpa_check_header(uint32_t header){
63 /* header */
64
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124734777 if ((header & 0xffe00000) != 0xffe00000)
65 124208653 return -1;
66 /* version check */
67
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526124 if ((header & (3<<19)) == 1<<19)
68 88956 return -1;
69 /* layer check */
70
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437168 if ((header & (3<<17)) == 0)
71 78238 return -1;
72 /* bit rate */
73
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358930 if ((header & (0xf<<12)) == 0xf<<12)
74 246348 return -1;
75 /* frequency */
76
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112582 if ((header & (3<<10)) == 3<<10)
77 16832 return -1;
78 95750 return 0;
79 }
80
81 #endif /* AVCODEC_MPEGAUDIODECHEADER_H */
82