2 * Audio and Video frame extraction
3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2003 Michael Niedermayer
6 * This file is part of FFmpeg.
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.
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.
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
24 #include "aac_ac3_parser.h"
25 #include "aac_parser.h"
27 #include "mpeg4audio.h"
29 int ff_aac_parse_header(GetBitContext *gbc, AACADTSHeaderInfo *hdr)
31 int size, rdb, ch, sr;
34 if(get_bits(gbc, 12) != 0xfff)
35 return AAC_AC3_PARSE_ERROR_SYNC;
37 skip_bits1(gbc); /* id */
38 skip_bits(gbc, 2); /* layer */
39 crc_abs = get_bits1(gbc); /* protection_absent */
40 aot = get_bits(gbc, 2); /* profile_objecttype */
41 sr = get_bits(gbc, 4); /* sample_frequency_index */
42 if(!ff_mpeg4audio_sample_rates[sr])
43 return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
44 skip_bits1(gbc); /* private_bit */
45 ch = get_bits(gbc, 3); /* channel_configuration */
47 if(!ff_mpeg4audio_channels[ch])
48 return AAC_AC3_PARSE_ERROR_CHANNEL_CFG;
50 skip_bits1(gbc); /* original/copy */
51 skip_bits1(gbc); /* home */
53 /* adts_variable_header */
54 skip_bits1(gbc); /* copyright_identification_bit */
55 skip_bits1(gbc); /* copyright_identification_start */
56 size = get_bits(gbc, 13); /* aac_frame_length */
57 if(size < AAC_ADTS_HEADER_SIZE)
58 return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
60 skip_bits(gbc, 11); /* adts_buffer_fullness */
61 rdb = get_bits(gbc, 2); /* number_of_raw_data_blocks_in_frame */
63 hdr->object_type = aot + 1;
64 hdr->chan_config = ch;
65 hdr->crc_absent = crc_abs;
66 hdr->num_aac_frames = rdb + 1;
67 hdr->sampling_index = sr;
68 hdr->sample_rate = ff_mpeg4audio_sample_rates[sr];
69 hdr->samples = (rdb + 1) * 1024;
70 hdr->bit_rate = size * 8 * hdr->sample_rate / hdr->samples;
75 static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info,
76 int *need_next_header, int *new_frame_start)
79 AACADTSHeaderInfo hdr;
86 tmp.u64 = be2me_64(state);
87 init_get_bits(&bits, tmp.u8+8-AAC_ADTS_HEADER_SIZE, AAC_ADTS_HEADER_SIZE * 8);
89 if ((size = ff_aac_parse_header(&bits, &hdr)) < 0)
91 *need_next_header = 0;
93 hdr_info->sample_rate = hdr.sample_rate;
94 hdr_info->channels = ff_mpeg4audio_channels[hdr.chan_config];
95 hdr_info->samples = hdr.samples;
96 hdr_info->bit_rate = hdr.bit_rate;
100 static av_cold int aac_parse_init(AVCodecParserContext *s1)
102 AACAC3ParseContext *s = s1->priv_data;
103 s->header_size = AAC_ADTS_HEADER_SIZE;
109 AVCodecParser aac_parser = {
111 sizeof(AACAC3ParseContext),