1/*
2 * JPEG-LS common code
3 * Copyright (c) 2003 Michael Niedermayer
4 * Copyright (c) 2006 Konstantin Shishkov
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * JPEG-LS common code.
26 */
27
28#include "jpegls.h"
29
30void ff_jpegls_init_state(JLSState *state){
31    int i;
32
33    state->twonear = state->near * 2 + 1;
34    state->range = ((state->maxval + state->twonear - 1) / state->twonear) + 1;
35
36    // QBPP = ceil(log2(RANGE))
37    for(state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++);
38
39    if(state->bpp < 8)
40        state->limit = 16 + 2 * state->bpp - state->qbpp;
41    else
42        state->limit = (4 * state->bpp) - state->qbpp;
43
44    for(i = 0; i < 367; i++) {
45        state->A[i] = FFMAX((state->range + 32) >> 6, 2);
46        state->N[i] = 1;
47    }
48
49}
50
51/**
52 * Custom value clipping function used in T1, T2, T3 calculation
53 */
54static inline int iso_clip(int v, int vmin, int vmax){
55    if(v > vmax || v < vmin) return vmin;
56    else                     return v;
57}
58
59void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all){
60    const int basic_t1= 3;
61    const int basic_t2= 7;
62    const int basic_t3= 21;
63    int factor;
64
65    if(s->maxval==0 || reset_all) s->maxval= (1 << s->bpp) - 1;
66
67    if(s->maxval >=128){
68        factor= (FFMIN(s->maxval, 4095) + 128)>>8;
69
70        if(s->T1==0     || reset_all)
71            s->T1= iso_clip(factor*(basic_t1-2) + 2 + 3*s->near, s->near+1, s->maxval);
72        if(s->T2==0     || reset_all)
73            s->T2= iso_clip(factor*(basic_t2-3) + 3 + 5*s->near, s->T1, s->maxval);
74        if(s->T3==0     || reset_all)
75            s->T3= iso_clip(factor*(basic_t3-4) + 4 + 7*s->near, s->T2, s->maxval);
76    }else{
77        factor= 256 / (s->maxval + 1);
78
79        if(s->T1==0     || reset_all)
80            s->T1= iso_clip(FFMAX(2, basic_t1/factor + 3*s->near), s->near+1, s->maxval);
81        if(s->T2==0     || reset_all)
82            s->T2= iso_clip(FFMAX(3, basic_t2/factor + 5*s->near), s->T1, s->maxval);
83        if(s->T3==0     || reset_all)
84            s->T3= iso_clip(FFMAX(4, basic_t3/factor + 7*s->near), s->T2, s->maxval);
85    }
86
87    if(s->reset==0  || reset_all) s->reset= 64;
88//    av_log(NULL, AV_LOG_DEBUG, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);
89}
90