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84 lines
2.7 KiB
84 lines
2.7 KiB
/* |
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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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int ff_ac3_find_syncword(const uint8_t *buf, int buf_size); |
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#endif /* AVCODEC_AC3_PARSER_INTERNAL_H */
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