71 lines
2.2 KiB
C
71 lines
2.2 KiB
C
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/*
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* Shared functions between AMR codecs
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*
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* Copyright (c) 2010 Marcelo Galvao Povoa
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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_AMR_H
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#define AVCODEC_AMR_H
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#include <string.h>
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#include "avcodec.h"
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#ifdef AMR_USE_16BIT_TABLES
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typedef uint16_t R_TABLE_TYPE;
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#else
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typedef uint8_t R_TABLE_TYPE;
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#endif
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/**
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* Fill the frame structure variables from bitstream by parsing the
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* given reordering table that uses the following format:
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*
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* Each field (16 bits) in the AMR Frame is stored as:
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* - one byte for the number of bits in the field
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* - one byte for the field index
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* - then, one byte for each bit of the field (from most-significant to least)
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* of the position of that bit in the AMR frame.
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*
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* @param out pointer to the frame struct
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* @param size the size in bytes of the frame struct
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* @param data input bitstream after the frame header
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* @param ord_table the reordering table as above
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*/
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static inline void ff_amr_bit_reorder(uint16_t *out, int size,
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const uint8_t *data,
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const R_TABLE_TYPE *ord_table)
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{
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int field_size;
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memset(out, 0, size);
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while ((field_size = *ord_table++)) {
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int field = 0;
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int field_offset = *ord_table++;
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while (field_size--) {
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int bit = *ord_table++;
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field <<= 1;
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field |= data[bit >> 3] >> (bit & 7) & 1;
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}
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out[field_offset >> 1] = field;
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}
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}
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#endif /* AVCODEC_AMR_H */
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