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 const uint8_t ff_log2_run
[32]={
31 0, 0, 0, 0, 1, 1, 1, 1,
32 2, 2, 2, 2, 3, 3, 3, 3,
33 4, 4, 5, 5, 6, 6, 7, 7,
34 8, 9,10,11,12,13,14,15
37 void ff_jpegls_init_state(JLSState
*state
){
40 state
->twonear
= state
->near
* 2 + 1;
41 state
->range
= ((state
->maxval
+ state
->twonear
- 1) / state
->twonear
) + 1;
43 // QBPP = ceil(log2(RANGE))
44 for(state
->qbpp
= 0; (1 << state
->qbpp
) < state
->range
; state
->qbpp
++);
47 state
->limit
= 16 + 2 * state
->bpp
- state
->qbpp
;
49 state
->limit
= (4 * state
->bpp
) - state
->qbpp
;
51 for(i
= 0; i
< 367; i
++) {
52 state
->A
[i
] = FFMAX((state
->range
+ 32) >> 6, 2);
59 * Custom value clipping function used in T1, T2, T3 calculation
61 static inline int iso_clip(int v
, int vmin
, int vmax
){
62 if(v
> vmax
|| v
< vmin
) return vmin
;
66 void ff_jpegls_reset_coding_parameters(JLSState
*s
, int reset_all
){
67 const int basic_t1
= 3;
68 const int basic_t2
= 7;
69 const int basic_t3
= 21;
72 if(s
->maxval
==0 || reset_all
) s
->maxval
= (1 << s
->bpp
) - 1;
75 factor
= (FFMIN(s
->maxval
, 4095) + 128)>>8;
77 if(s
->T1
==0 || reset_all
)
78 s
->T1
= iso_clip(factor
*(basic_t1
-2) + 2 + 3*s
->near
, s
->near
+1, s
->maxval
);
79 if(s
->T2
==0 || reset_all
)
80 s
->T2
= iso_clip(factor
*(basic_t2
-3) + 3 + 5*s
->near
, s
->T1
, s
->maxval
);
81 if(s
->T3
==0 || reset_all
)
82 s
->T3
= iso_clip(factor
*(basic_t3
-4) + 4 + 7*s
->near
, s
->T2
, s
->maxval
);
84 factor
= 256 / (s
->maxval
+ 1);
86 if(s
->T1
==0 || reset_all
)
87 s
->T1
= iso_clip(FFMAX(2, basic_t1
/factor
+ 3*s
->near
), s
->near
+1, s
->maxval
);
88 if(s
->T2
==0 || reset_all
)
89 s
->T2
= iso_clip(FFMAX(3, basic_t2
/factor
+ 5*s
->near
), s
->T1
, s
->maxval
);
90 if(s
->T3
==0 || reset_all
)
91 s
->T3
= iso_clip(FFMAX(4, basic_t3
/factor
+ 6*s
->near
), s
->T2
, s
->maxval
);
94 if(s
->reset
==0 || reset_all
) s
->reset
= 64;
95 // av_log(NULL, AV_LOG_DEBUG, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);