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Required by MP4's AC3SpecificBox and MPEG-TS AC-3 audio_descriptor, of which the former is implemented in our MP4 writer. Signed-off-by: Jan Ekström <jan.ekstrom@24i.com>
83 lines
2.6 KiB
C
83 lines
2.6 KiB
C
/*
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* AC-3 parser internal code
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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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#ifndef AVCODEC_AC3_PARSER_INTERNAL_H
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#define AVCODEC_AC3_PARSER_INTERNAL_H
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#include <stddef.h>
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#include <stdint.h>
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#include "ac3defs.h"
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#include "get_bits.h"
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/**
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* @struct AC3HeaderInfo
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* Coded AC-3 header values up to the lfeon element, plus derived values.
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*/
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typedef struct AC3HeaderInfo {
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/** @name Coded elements
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* @{
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*/
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uint16_t sync_word;
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uint16_t crc1;
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uint8_t sr_code;
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uint8_t bitstream_id;
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uint8_t bitstream_mode;
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uint8_t channel_mode;
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uint8_t lfe_on;
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uint8_t frame_type;
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int substreamid; ///< substream identification
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int center_mix_level; ///< Center mix level index
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int surround_mix_level; ///< Surround mix level index
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uint16_t channel_map;
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int num_blocks; ///< number of audio blocks
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int dolby_surround_mode;
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/** @} */
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/** @name Derived values
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* @{
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*/
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uint8_t sr_shift;
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uint16_t sample_rate;
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uint32_t bit_rate;
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uint8_t channels;
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uint16_t frame_size;
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uint64_t channel_layout;
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int8_t ac3_bit_rate_code;
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/** @} */
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} AC3HeaderInfo;
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/**
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* Parse AC-3 frame header.
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* Parse the header up to the lfeon element, which is the first 52 or 54 bits
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* depending on the audio coding mode.
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* @param[in] gbc BitContext containing the first 54 bits of the frame.
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* @param[out] hdr Pointer to struct where header info is written.
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* @return Returns 0 on success, -1 if there is a sync word mismatch,
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* -2 if the bsid (version) element is invalid, -3 if the fscod (sample rate)
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* element is invalid, or -4 if the frmsizecod (bit rate) element is invalid.
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*/
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int ff_ac3_parse_header(GetBitContext *gbc, AC3HeaderInfo *hdr);
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int avpriv_ac3_parse_header(AC3HeaderInfo **hdr, const uint8_t *buf,
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size_t size);
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#endif /* AVCODEC_AC3_PARSER_INTERNAL_H */
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