Corrections of errors in aac_ac3_parser
[libav.git] / libavcodec / aac_parser.c
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1/*
2 * Audio and Video frame extraction
3 * Copyright (c) 2003 Fabrice Bellard.
4 * Copyright (c) 2003 Michael Niedermayer.
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#include "parser.h"
24#include "aac_ac3_parser.h"
25#include "bitstream.h"
bac47ae6 26#include "mpeg4audio.h"
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27
28#define AAC_HEADER_SIZE 7
29
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30static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info,
31 int *need_next_header, int *new_frame_start)
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32{
33 GetBitContext bits;
34 int size, rdb, ch, sr;
0a5754c3 35 uint64_t tmp = be2me_64(state);
99ff31dc 36
c09ed33e 37 init_get_bits(&bits, ((uint8_t *)&tmp)+8-AAC_HEADER_SIZE, AAC_HEADER_SIZE * 8);
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38
39 if(get_bits(&bits, 12) != 0xfff)
40 return 0;
41
42 skip_bits1(&bits); /* id */
43 skip_bits(&bits, 2); /* layer */
44 skip_bits1(&bits); /* protection_absent */
45 skip_bits(&bits, 2); /* profile_objecttype */
46 sr = get_bits(&bits, 4); /* sample_frequency_index */
bac47ae6 47 if(!ff_mpeg4audio_sample_rates[sr])
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48 return 0;
49 skip_bits1(&bits); /* private_bit */
50 ch = get_bits(&bits, 3); /* channel_configuration */
bac47ae6 51 if(!ff_mpeg4audio_channels[ch])
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52 return 0;
53 skip_bits1(&bits); /* original/copy */
54 skip_bits1(&bits); /* home */
55
56 /* adts_variable_header */
57 skip_bits1(&bits); /* copyright_identification_bit */
58 skip_bits1(&bits); /* copyright_identification_start */
59 size = get_bits(&bits, 13); /* aac_frame_length */
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60 if(size < AAC_HEADER_SIZE)
61 return 0;
62
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63 skip_bits(&bits, 11); /* adts_buffer_fullness */
64 rdb = get_bits(&bits, 2); /* number_of_raw_data_blocks_in_frame */
65
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66 hdr_info->channels = ff_mpeg4audio_channels[ch];
67 hdr_info->sample_rate = ff_mpeg4audio_sample_rates[sr];
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68 hdr_info->samples = (rdb + 1) * 1024;
69 hdr_info->bit_rate = size * 8 * hdr_info->sample_rate / hdr_info->samples;
99ff31dc 70
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71 *need_next_header=0;
72 *new_frame_start=1;
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73 return size;
74}
75
98a6fff9 76static av_cold int aac_parse_init(AVCodecParserContext *s1)
99ff31dc 77{
679c2294 78 AACAC3ParseContext *s = s1->priv_data;
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79 s->header_size = AAC_HEADER_SIZE;
80 s->sync = aac_sync;
81 return 0;
82}
83
84
85AVCodecParser aac_parser = {
86 { CODEC_ID_AAC },
679c2294 87 sizeof(AACAC3ParseContext),
99ff31dc 88 aac_parse_init,
679c2294 89 ff_aac_ac3_parse,
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90 NULL,
91};