mirror of https://github.com/FFmpeg/FFmpeg.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
117 lines
3.6 KiB
117 lines
3.6 KiB
/* |
|
* Audio and Video frame extraction |
|
* Copyright (c) 2003 Fabrice Bellard |
|
* Copyright (c) 2003 Michael Niedermayer |
|
* |
|
* 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 "parser.h" |
|
#include "aac_ac3_parser.h" |
|
#include "aac_parser.h" |
|
#include "bitstream.h" |
|
#include "mpeg4audio.h" |
|
|
|
#define AAC_HEADER_SIZE 7 |
|
|
|
int ff_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(!ff_mpeg4audio_sample_rates[sr]) |
|
return AAC_AC3_PARSE_ERROR_SAMPLE_RATE; |
|
skip_bits1(gbc); /* private_bit */ |
|
ch = get_bits(gbc, 3); /* channel_configuration */ |
|
|
|
if(!ff_mpeg4audio_channels[ch]) |
|
return AAC_AC3_PARSE_ERROR_CHANNEL_CFG; |
|
|
|
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_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 = ff_mpeg4audio_sample_rates[sr]; |
|
hdr->samples = (rdb + 1) * 1024; |
|
hdr->bit_rate = size * 8 * hdr->sample_rate / hdr->samples; |
|
|
|
return size; |
|
} |
|
|
|
static int aac_sync(uint64_t state, AACAC3ParseContext *hdr_info, |
|
int *need_next_header, int *new_frame_start) |
|
{ |
|
GetBitContext bits; |
|
AACADTSHeaderInfo hdr; |
|
int size; |
|
union { |
|
uint64_t u64; |
|
uint8_t u8[8]; |
|
} tmp; |
|
|
|
tmp.u64 = be2me_64(state); |
|
init_get_bits(&bits, tmp.u8+8-AAC_HEADER_SIZE, AAC_HEADER_SIZE * 8); |
|
|
|
if ((size = ff_aac_parse_header(&bits, &hdr)) < 0) |
|
return 0; |
|
*need_next_header = 0; |
|
*new_frame_start = 1; |
|
hdr_info->sample_rate = hdr.sample_rate; |
|
hdr_info->channels = ff_mpeg4audio_channels[hdr.chan_config]; |
|
hdr_info->samples = hdr.samples; |
|
hdr_info->bit_rate = hdr.bit_rate; |
|
return size; |
|
} |
|
|
|
static av_cold int aac_parse_init(AVCodecParserContext *s1) |
|
{ |
|
AACAC3ParseContext *s = s1->priv_data; |
|
s->header_size = AAC_HEADER_SIZE; |
|
s->sync = aac_sync; |
|
return 0; |
|
} |
|
|
|
|
|
AVCodecParser aac_parser = { |
|
{ CODEC_ID_AAC }, |
|
sizeof(AACAC3ParseContext), |
|
aac_parse_init, |
|
ff_aac_ac3_parse, |
|
NULL, |
|
};
|
|
|