mirror of
https://github.com/FFmpeg/FFmpeg.git
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eee5fa0808
This commit adds a decoder for the frequency-domain part of USAC. What works: - Mono - Stereo (no prediction) - Stereo (mid/side coding) - Stereo (complex prediction) What's left: - SBR - Speech coding Known issues: - Desync with certain sequences - Preroll crossover missing (shouldn't matter, bitrate adaptation only)
55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
/*
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* AAC definitions and structures
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* Copyright (c) 2024 Lynne
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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_AAC_AACDEC_AC_H
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#define AVCODEC_AAC_AACDEC_AC_H
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#include "libavcodec/get_bits.h"
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typedef struct AACArithState {
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uint8_t last[512 /* 2048 / 4 */];
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int last_len;
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uint8_t cur[4];
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uint16_t state_pre;
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} AACArithState;
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typedef struct AACArith {
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uint16_t low;
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uint16_t high;
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uint16_t val;
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} AACArith;
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#define FF_AAC_AC_ESCAPE 16
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uint32_t ff_aac_ac_map_process(AACArithState *state, int reset, int len);
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uint32_t ff_aac_ac_get_context(AACArithState *state, uint32_t old_c, int idx, int len);
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uint32_t ff_aac_ac_get_pk(uint32_t c);
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void ff_aac_ac_update_context(AACArithState *state, int idx, uint16_t a, uint16_t b);
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void ff_aac_ac_init(AACArith *ac, GetBitContext *gb);
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uint16_t ff_aac_ac_decode(AACArith *ac, GetBitContext *gb,
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const uint16_t *cdf, uint16_t cdf_len);
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void ff_aac_ac_finish(AACArithState *state, int offset, int nb);
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#endif /* AVCODEC_AACDEC_AC_H */
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