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/*
* JPEG-LS common code
* Copyright (c) 2003 Michael Niedermayer
* Copyright (c) 2006 Konstantin Shishkov
*
* 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
*/
/**
* @file
* JPEG-LS common code.
*/
#ifndef AVCODEC_JPEGLS_H
#define AVCODEC_JPEGLS_H
#include "libavutil/common.h"
#include "avcodec.h"
#include "internal.h"
typedef struct JpeglsContext {
AVCodecContext *avctx;
} JpeglsContext;
typedef struct JLSState {
int T1, T2, T3;
int A[367], B[367], C[365], N[367];
int limit, reset, bpp, qbpp, maxval, range;
int near, twonear;
int run_index[4];
} JLSState;
/**
* Calculate initial JPEG-LS parameters
*/
void ff_jpegls_init_state(JLSState *state);
/**
* Calculate quantized gradient value, used for context determination
*/
static inline int ff_jpegls_quantize(JLSState *s, int v)
{
if (v == 0)
return 0;
if (v < 0) {
if (v <= -s->T3)
return -4;
if (v <= -s->T2)
return -3;
if (v <= -s->T1)
return -2;
if (v < -s->near)
return -1;
return 0;
} else {
if (v <= s->near)
return 0;
if (v < s->T1)
return 1;
if (v < s->T2)
return 2;
if (v < s->T3)
return 3;
return 4;
}
}
/**
* Calculate JPEG-LS codec values
*/
void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
{
if (state->N[Q] == state->reset) {
state->A[Q] >>= 1;
state->B[Q] >>= 1;
state->N[Q] >>= 1;
}
state->N[Q]++;
}
static inline int ff_jpegls_update_state_regular(JLSState *state,
int Q, int err)
{
if(FFABS(err) > 0xFFFF)
return -0x10000;
state->A[Q] += FFABS(err);
err *= state->twonear;
state->B[Q] += err;
ff_jpegls_downscale_state(state, Q);
if (state->B[Q] <= -state->N[Q]) {
state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
if (state->C[Q] > -128)
state->C[Q]--;
} else if (state->B[Q] > 0) {
state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
if (state->C[Q] < 127)
state->C[Q]++;
}
return err;
}
#define R(a, i) (bits == 8 ? ((uint8_t *)(a))[i] : ((uint16_t *)(a))[i])
#define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
#endif /* AVCODEC_JPEGLS_H */
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