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https://github.com/FFmpeg/FFmpeg.git
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12ded9cd85
Most users of ff_adts_header_parse() don't already have an opened GetBitContext for the header, so add a convenience function for them. Also use a forward declaration of GetBitContext in adts_header.h as this avoids (implicit) inclusion of get_bits.h in some of the users that now no longer use a GetBitContext of their own. Reviewed-by: James Almer <jamrial@gmail.com> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
84 lines
2.9 KiB
C
84 lines
2.9 KiB
C
/*
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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 "adts_header.h"
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#include "adts_parser.h"
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#include "get_bits.h"
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#include "mpeg4audio.h"
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#include "libavutil/avassert.h"
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int ff_adts_header_parse(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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memset(hdr, 0, sizeof(*hdr));
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if (get_bits(gbc, 12) != 0xfff)
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return AAC_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 (!ff_mpeg4audio_sample_rates[sr])
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return AAC_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 < AV_AAC_ADTS_HEADER_SIZE)
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return AAC_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 = ff_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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hdr->frame_length = size;
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return size;
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}
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int ff_adts_header_parse_buf(const uint8_t buf[AV_AAC_ADTS_HEADER_SIZE + AV_INPUT_BUFFER_PADDING_SIZE],
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AACADTSHeaderInfo *hdr)
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{
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GetBitContext gb;
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av_unused int ret = init_get_bits8(&gb, buf, AV_AAC_ADTS_HEADER_SIZE);
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av_assert1(ret >= 0);
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return ff_adts_header_parse(&gb, hdr);
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}
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