3 * Copyright (c) 2003 Michael Niedermayer
4 * Copyright (c) 2006 Konstantin Shishkov
6 * This file is part of FFmpeg.
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.
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.
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
25 * JPEG-LS common code.
30 void ff_jpegls_init_state(JLSState *state){
33 state->twonear = state->near * 2 + 1;
34 state->range = ((state->maxval + state->twonear - 1) / state->twonear) + 1;
36 // QBPP = ceil(log2(RANGE))
37 for(state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++);
39 state->bpp = FFMAX(av_log2(state->maxval)+1, 2);
40 state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp;
42 for(i = 0; i < 367; i++) {
43 state->A[i] = FFMAX((state->range + 32) >> 6, 2);
50 * Custom value clipping function used in T1, T2, T3 calculation
52 static inline int iso_clip(int v, int vmin, int vmax){
53 if(v > vmax || v < vmin) return vmin;
57 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all){
58 const int basic_t1= 3;
59 const int basic_t2= 7;
60 const int basic_t3= 21;
63 if(s->maxval==0 || reset_all) s->maxval= (1 << s->bpp) - 1;
66 factor= (FFMIN(s->maxval, 4095) + 128)>>8;
68 if(s->T1==0 || reset_all)
69 s->T1= iso_clip(factor*(basic_t1-2) + 2 + 3*s->near, s->near+1, s->maxval);
70 if(s->T2==0 || reset_all)
71 s->T2= iso_clip(factor*(basic_t2-3) + 3 + 5*s->near, s->T1, s->maxval);
72 if(s->T3==0 || reset_all)
73 s->T3= iso_clip(factor*(basic_t3-4) + 4 + 7*s->near, s->T2, s->maxval);
75 factor= 256 / (s->maxval + 1);
77 if(s->T1==0 || reset_all)
78 s->T1= iso_clip(FFMAX(2, basic_t1/factor + 3*s->near), s->near+1, s->maxval);
79 if(s->T2==0 || reset_all)
80 s->T2= iso_clip(FFMAX(3, basic_t2/factor + 5*s->near), s->T1, s->maxval);
81 if(s->T3==0 || reset_all)
82 s->T3= iso_clip(FFMAX(4, basic_t3/factor + 7*s->near), s->T2, s->maxval);
85 if(s->reset==0 || reset_all) s->reset= 64;
86 av_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);