| 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 | #ifndef AVCODEC_MPEGAUDIODECHEADER_H | ||
| 28 | #define AVCODEC_MPEGAUDIODECHEADER_H | ||
| 29 | |||
| 30 | #include <stdint.h> | ||
| 31 | |||
| 32 | #include "libavutil/attributes.h" | ||
| 33 | |||
| 34 | #include "codec_id.h" | ||
| 35 | #include "version_major.h" | ||
| 36 | |||
| 37 | #define MP3_MASK 0xFFFE0CCF | ||
| 38 | |||
| 39 | #define FF_MPEGAUDIO_LEGACY_DECODE_HEADER (LIBAVCODEC_VERSION_MAJOR < 64) | ||
| 40 | |||
| 41 | #if FF_MPEGAUDIO_LEGACY_DECODE_HEADER | ||
| 42 | #define MPA_DECODE_HEADER \ | ||
| 43 | int frame_size; \ | ||
| 44 | int error_protection; \ | ||
| 45 | int layer; \ | ||
| 46 | int sample_rate; \ | ||
| 47 | int sample_rate_index; /* between 0 and 8 */ \ | ||
| 48 | int bit_rate; \ | ||
| 49 | int nb_channels; \ | ||
| 50 | int mode; \ | ||
| 51 | int mode_ext; \ | ||
| 52 | int lsf; | ||
| 53 | |||
| 54 | typedef struct MPADecodeHeader { | ||
| 55 | MPA_DECODE_HEADER | ||
| 56 | } MPADecodeHeader; | ||
| 57 | |||
| 58 | /* header decoding. MUST check the header before because no | ||
| 59 | consistency check is done there. Return 1 if free format found and | ||
| 60 | that the frame size must be computed externally */ | ||
| 61 | int avpriv_mpegaudio_decode_header(MPADecodeHeader *s, uint32_t header); | ||
| 62 | #endif | ||
| 63 | |||
| 64 | /** | ||
| 65 | * Same as MPADecodeHeader, plus the header fields that carry no decoding | ||
| 66 | * information. Its size is not part of the libavcodec ABI: it is only ever | ||
| 67 | * allocated by avpriv_mpegaudio_decode_header2(). | ||
| 68 | */ | ||
| 69 | typedef struct MPADecodeHeader2 { | ||
| 70 | int frame_size; | ||
| 71 | int error_protection; | ||
| 72 | int layer; | ||
| 73 | int sample_rate; | ||
| 74 | int sample_rate_index; /* between 0 and 8 */ | ||
| 75 | int bit_rate; | ||
| 76 | int nb_channels; | ||
| 77 | int mode; | ||
| 78 | int mode_ext; | ||
| 79 | int lsf; | ||
| 80 | int copyright; | ||
| 81 | int original; | ||
| 82 | int emphasis; | ||
| 83 | int bitrate_index; | ||
| 84 | int padding; | ||
| 85 | int private_bit; | ||
| 86 | } MPADecodeHeader2; | ||
| 87 | |||
| 88 | /** | ||
| 89 | * Decode an MPEG audio header into *phdr, which is allocated if it is NULL. | ||
| 90 | * | ||
| 91 | * The header must have been checked beforehand, as no consistency check is | ||
| 92 | * done here. | ||
| 93 | * | ||
| 94 | * @return 1 if free format was found and the frame size must be computed | ||
| 95 | * externally, 0 on success, a negative AVERROR code on failure | ||
| 96 | */ | ||
| 97 | int avpriv_mpegaudio_decode_header2(MPADecodeHeader2 **phdr, uint32_t header); | ||
| 98 | |||
| 99 | /* same as avpriv_mpegaudio_decode_header2(), for callers within libavcodec, | ||
| 100 | which are built against this very header and may allocate it themselves */ | ||
| 101 | int ff_mpegaudio_decode_header(MPADecodeHeader2 *s, uint32_t header); | ||
| 102 | |||
| 103 | /* useful helper to get MPEG audio stream info. Return -1 if error in | ||
| 104 | header, otherwise the coded frame size in bytes */ | ||
| 105 | int ff_mpa_decode_header(uint32_t head, int *sample_rate, | ||
| 106 | int *channels, int *frame_size, int *bitrate, enum AVCodecID *codec_id); | ||
| 107 | |||
| 108 | /* fast header check for resync */ | ||
| 109 | 464287831 | static inline int ff_mpa_check_header(uint32_t header){ | |
| 110 | /* header */ | ||
| 111 |
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464287831 | if ((header & 0xffe00000) != 0xffe00000) |
| 112 | 463001586 | return -1; | |
| 113 | /* version check */ | ||
| 114 |
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1286245 | if ((header & (3<<19)) == 1<<19) |
| 115 | 246332 | return -1; | |
| 116 | /* layer check */ | ||
| 117 |
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1039913 | if ((header & (3<<17)) == 0) |
| 118 | 235998 | return -1; | |
| 119 | /* bit rate */ | ||
| 120 |
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803915 | if ((header & (0xf<<12)) == 0xf<<12) |
| 121 | 541884 | return -1; | |
| 122 | /* frequency */ | ||
| 123 |
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262031 | if ((header & (3<<10)) == 3<<10) |
| 124 | 35714 | return -1; | |
| 125 | 226317 | return 0; | |
| 126 | } | ||
| 127 | |||
| 128 | 683 | static inline uint32_t ff_mpa_encode_header(const MPADecodeHeader2 *s) | |
| 129 | { | ||
| 130 |
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683 | int version = s->sample_rate_index < 6 ? 3 - s->sample_rate_index / 3 : 0; |
| 131 | |||
| 132 | return 0xffeU << 20 | | ||
| 133 | 683 | version << 19 | | |
| 134 | 1366 | (4 - s->layer) << 17 | | |
| 135 |
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683 | !s->error_protection << 16 | |
| 136 | 683 | s->bitrate_index << 12 | | |
| 137 | 683 | s->sample_rate_index % 3 << 10 | | |
| 138 | 683 | s->padding << 9 | | |
| 139 | 683 | s->private_bit << 8 | | |
| 140 | 683 | s->mode << 6 | | |
| 141 | 683 | s->mode_ext << 4 | | |
| 142 | 683 | s->copyright << 3 | | |
| 143 | 1366 | s->original << 2 | | |
| 144 | 683 | s->emphasis; | |
| 145 | } | ||
| 146 | |||
| 147 | #endif /* AVCODEC_MPEGAUDIODECHEADER_H */ | ||
| 148 |