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libavcodec
aacadtsdec.c
Go to the documentation of this file.
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/*
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* Audio and Video frame extraction
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* Copyright (c) 2003 Fabrice Bellard
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* Copyright (c) 2003 Michael Niedermayer
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* Copyright (c) 2009 Alex Converse
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "
aac_ac3_parser.h
"
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#include "
aacadtsdec.h
"
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#include "
get_bits.h
"
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#include "
mpeg4audio.h
"
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int
avpriv_aac_parse_header
(
GetBitContext
*gbc,
AACADTSHeaderInfo
*hdr)
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{
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int
size
, rdb, ch, sr;
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int
aot, crc_abs;
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if
(
get_bits
(gbc, 12) != 0xfff)
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return
AAC_AC3_PARSE_ERROR_SYNC
;
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skip_bits1
(gbc);
/* id */
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skip_bits
(gbc, 2);
/* layer */
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crc_abs =
get_bits1
(gbc);
/* protection_absent */
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aot =
get_bits
(gbc, 2);
/* profile_objecttype */
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sr =
get_bits
(gbc, 4);
/* sample_frequency_index */
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if
(!
avpriv_mpeg4audio_sample_rates
[sr])
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return
AAC_AC3_PARSE_ERROR_SAMPLE_RATE
;
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skip_bits1
(gbc);
/* private_bit */
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ch =
get_bits
(gbc, 3);
/* channel_configuration */
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skip_bits1
(gbc);
/* original/copy */
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skip_bits1
(gbc);
/* home */
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/* adts_variable_header */
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skip_bits1
(gbc);
/* copyright_identification_bit */
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skip_bits1
(gbc);
/* copyright_identification_start */
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size =
get_bits
(gbc, 13);
/* aac_frame_length */
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if
(size <
AAC_ADTS_HEADER_SIZE
)
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return
AAC_AC3_PARSE_ERROR_FRAME_SIZE
;
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skip_bits
(gbc, 11);
/* adts_buffer_fullness */
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rdb =
get_bits
(gbc, 2);
/* number_of_raw_data_blocks_in_frame */
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hdr->
object_type
= aot + 1;
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hdr->
chan_config
= ch;
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hdr->
crc_absent
= crc_abs;
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hdr->
num_aac_frames
= rdb + 1;
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hdr->
sampling_index
= sr;
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hdr->
sample_rate
=
avpriv_mpeg4audio_sample_rates
[sr];
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hdr->
samples
= (rdb + 1) * 1024;
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hdr->
bit_rate
= size * 8 * hdr->
sample_rate
/ hdr->
samples
;
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return
size
;
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}
Generated on Wed Jul 10 2013 23:47:54 for FFmpeg by
1.8.2