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/*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_APV_DECODE_H
#define AVCODEC_APV_DECODE_H
#include <stdint.h>
#include "apv.h"
#include "avcodec.h"
#include "get_bits.h"
// Number of bits in the entropy look-up tables.
// It may be desirable to tune this per-architecture, as a larger LUT
// trades greater memory use for fewer instructions.
// (N bits -> 24*2^N bytes of tables; 9 -> 12KB of tables.)
#define APV_VLC_LUT_BITS 9
#define APV_VLC_LUT_SIZE (1 << APV_VLC_LUT_BITS)
typedef struct APVVLCLUTEntry {
uint16_t result; // Return value if not reading more.
uint8_t consume; // Number of bits to consume.
uint8_t more; // Whether to read additional bits.
} APVVLCLUTEntry;
typedef struct APVVLCLUT {
APVVLCLUTEntry lut[6][APV_VLC_LUT_SIZE];
} APVVLCLUT;
typedef struct APVEntropyState {
void *log_ctx;
const APVVLCLUT *decode_lut;
int16_t prev_dc;
int16_t prev_dc_diff;
int16_t prev_1st_ac_level;
} APVEntropyState;
/**
* Build the decoder VLC look-up table.
*/
void ff_apv_entropy_build_decode_lut(APVVLCLUT *decode_lut);
/**
* Entropy decode a single 8x8 block to coefficients.
*
* Outputs in block order (dezigzag already applied).
*/
int ff_apv_entropy_decode_block(int16_t *coeff,
GetBitContext *gbc,
APVEntropyState *state);
/**
* Read a single APV VLC code.
*
* This entrypoint is exposed for testing.
*/
unsigned int ff_apv_read_vlc(GetBitContext *gbc, int k_param,
const APVVLCLUT *lut);
#endif /* AVCODEC_APV_DECODE_H */
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