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 "bitstream.h"
26 #include "mpeg4audio.h"
28 #define AAC_HEADER_SIZE 7
30 static int aac_sync(AACAC3ParseContext *hdr_info, AACAC3FrameFlag *flag)
33 int size, rdb, ch, sr;
35 init_get_bits(&bits, hdr_info->inbuf, AAC_HEADER_SIZE * 8);
37 if(get_bits(&bits, 12) != 0xfff)
40 skip_bits1(&bits); /* id */
41 skip_bits(&bits, 2); /* layer */
42 skip_bits1(&bits); /* protection_absent */
43 skip_bits(&bits, 2); /* profile_objecttype */
44 sr = get_bits(&bits, 4); /* sample_frequency_index */
45 if(!ff_mpeg4audio_sample_rates[sr])
47 skip_bits1(&bits); /* private_bit */
48 ch = get_bits(&bits, 3); /* channel_configuration */
49 if(!ff_mpeg4audio_channels[ch])
51 skip_bits1(&bits); /* original/copy */
52 skip_bits1(&bits); /* home */
54 /* adts_variable_header */
55 skip_bits1(&bits); /* copyright_identification_bit */
56 skip_bits1(&bits); /* copyright_identification_start */
57 size = get_bits(&bits, 13); /* aac_frame_length */
58 if(size < AAC_HEADER_SIZE)
61 skip_bits(&bits, 11); /* adts_buffer_fullness */
62 rdb = get_bits(&bits, 2); /* number_of_raw_data_blocks_in_frame */
64 hdr_info->channels = ff_mpeg4audio_channels[ch];
65 hdr_info->sample_rate = ff_mpeg4audio_sample_rates[sr];
66 hdr_info->samples = (rdb + 1) * 1024;
67 hdr_info->bit_rate = size * 8 * hdr_info->sample_rate / hdr_info->samples;
68 *flag = FRAME_COMPLETE;
73 static av_cold int aac_parse_init(AVCodecParserContext *s1)
75 AACAC3ParseContext *s = s1->priv_data;
76 s->inbuf_ptr = s->inbuf;
77 s->header_size = AAC_HEADER_SIZE;
83 AVCodecParser aac_parser = {
85 sizeof(AACAC3ParseContext),