0,0 → 1,70 |
/* |
* Audio and Video frame extraction |
* Copyright (c) 2003 Fabrice Bellard |
* Copyright (c) 2003 Michael Niedermayer |
* Copyright (c) 2009 Alex Converse |
* |
* This file is part of FFmpeg. |
* |
* FFmpeg is free software; you can redistribute it and/or |
* modify it under the terms of the GNU Lesser General Public |
* License as published by the Free Software Foundation; either |
* version 2.1 of the License, or (at your option) any later version. |
* |
* FFmpeg is distributed in the hope that it will be useful, |
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
* Lesser General Public License for more details. |
* |
* You should have received a copy of the GNU Lesser General Public |
* License along with FFmpeg; if not, write to the Free Software |
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
*/ |
|
#include "aac_ac3_parser.h" |
#include "aacadtsdec.h" |
#include "get_bits.h" |
#include "mpeg4audio.h" |
|
int avpriv_aac_parse_header(GetBitContext *gbc, AACADTSHeaderInfo *hdr) |
{ |
int size, rdb, ch, sr; |
int aot, crc_abs; |
|
if(get_bits(gbc, 12) != 0xfff) |
return AAC_AC3_PARSE_ERROR_SYNC; |
|
skip_bits1(gbc); /* id */ |
skip_bits(gbc, 2); /* layer */ |
crc_abs = get_bits1(gbc); /* protection_absent */ |
aot = get_bits(gbc, 2); /* profile_objecttype */ |
sr = get_bits(gbc, 4); /* sample_frequency_index */ |
if(!avpriv_mpeg4audio_sample_rates[sr]) |
return AAC_AC3_PARSE_ERROR_SAMPLE_RATE; |
skip_bits1(gbc); /* private_bit */ |
ch = get_bits(gbc, 3); /* channel_configuration */ |
|
skip_bits1(gbc); /* original/copy */ |
skip_bits1(gbc); /* home */ |
|
/* adts_variable_header */ |
skip_bits1(gbc); /* copyright_identification_bit */ |
skip_bits1(gbc); /* copyright_identification_start */ |
size = get_bits(gbc, 13); /* aac_frame_length */ |
if(size < AAC_ADTS_HEADER_SIZE) |
return AAC_AC3_PARSE_ERROR_FRAME_SIZE; |
|
skip_bits(gbc, 11); /* adts_buffer_fullness */ |
rdb = get_bits(gbc, 2); /* number_of_raw_data_blocks_in_frame */ |
|
hdr->object_type = aot + 1; |
hdr->chan_config = ch; |
hdr->crc_absent = crc_abs; |
hdr->num_aac_frames = rdb + 1; |
hdr->sampling_index = sr; |
hdr->sample_rate = avpriv_mpeg4audio_sample_rates[sr]; |
hdr->samples = (rdb + 1) * 1024; |
hdr->bit_rate = size * 8 * hdr->sample_rate / hdr->samples; |
|
return size; |
} |