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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.
*/
#include "jpegls.h"
void ff_jpegls_init_state(JLSState *state){
int i;
state->twonear = state->near * 2 + 1;
state->range = ((state->maxval + state->twonear - 1) / state->twonear) + 1;
// QBPP = ceil(log2(RANGE))
for(state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++);
state->bpp = FFMAX(av_log2(state->maxval)+1, 2);
state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp;
for(i = 0; i < 367; i++) {
state->A[i] = FFMAX((state->range + 32) >> 6, 2);
state->N[i] = 1;
}
}
/**
* Custom value clipping function used in T1, T2, T3 calculation
*/
static inline int iso_clip(int v, int vmin, int vmax){
if(v > vmax || v < vmin) return vmin;
else return v;
}
void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all){
const int basic_t1= 3;
const int basic_t2= 7;
const int basic_t3= 21;
int factor;
if(s->maxval==0 || reset_all) s->maxval= (1 << s->bpp) - 1;
if(s->maxval >=128){
factor= (FFMIN(s->maxval, 4095) + 128)>>8;
if(s->T1==0 || reset_all)
s->T1= iso_clip(factor*(basic_t1-2) + 2 + 3*s->near, s->near+1, s->maxval);
if(s->T2==0 || reset_all)
s->T2= iso_clip(factor*(basic_t2-3) + 3 + 5*s->near, s->T1, s->maxval);
if(s->T3==0 || reset_all)
s->T3= iso_clip(factor*(basic_t3-4) + 4 + 7*s->near, s->T2, s->maxval);
}else{
factor= 256 / (s->maxval + 1);
if(s->T1==0 || reset_all)
s->T1= iso_clip(FFMAX(2, basic_t1/factor + 3*s->near), s->near+1, s->maxval);
if(s->T2==0 || reset_all)
s->T2= iso_clip(FFMAX(3, basic_t2/factor + 5*s->near), s->T1, s->maxval);
if(s->T3==0 || reset_all)
s->T3= iso_clip(FFMAX(4, basic_t3/factor + 7*s->near), s->T2, s->maxval);
}
if(s->reset==0 || reset_all) s->reset= 64;
// av_log(NULL, AV_LOG_DEBUG, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);
}
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