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
)
34 state
->twonear
= state
->near
* 2 + 1;
35 state
->range
= (state
->maxval
+ state
->twonear
- 1) / state
->twonear
+ 1;
37 // QBPP = ceil(log2(RANGE))
38 for (state
->qbpp
= 0; (1 << state
->qbpp
) < state
->range
; state
->qbpp
++)
41 state
->bpp
= FFMAX(av_log2(state
->maxval
) + 1, 2);
42 state
->limit
= 2*(state
->bpp
+ FFMAX(state
->bpp
, 8)) - state
->qbpp
;
44 for (i
= 0; i
< 367; i
++) {
45 state
->A
[i
] = FFMAX(state
->range
+ 32 >> 6, 2);
51 * Custom value clipping function used in T1, T2, T3 calculation
53 static inline int iso_clip(int v
, int vmin
, int vmax
)
55 if (v
> vmax
|| v
< vmin
)
61 void ff_jpegls_reset_coding_parameters(JLSState
*s
, int reset_all
)
63 const int basic_t1
= 3;
64 const int basic_t2
= 7;
65 const int basic_t3
= 21;
68 if (s
->maxval
== 0 || reset_all
)
69 s
->maxval
= (1 << s
->bpp
) - 1;
71 if (s
->maxval
>= 128) {
72 factor
= FFMIN(s
->maxval
, 4095) + 128 >> 8;
74 if (s
->T1
== 0 || reset_all
)
75 s
->T1
= iso_clip(factor
* (basic_t1
- 2) + 2 + 3 * s
->near
,
76 s
->near
+ 1, s
->maxval
);
77 if (s
->T2
== 0 || reset_all
)
78 s
->T2
= iso_clip(factor
* (basic_t2
- 3) + 3 + 5 * s
->near
,
80 if (s
->T3
== 0 || reset_all
)
81 s
->T3
= iso_clip(factor
* (basic_t3
- 4) + 4 + 7 * s
->near
,
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
),
88 s
->near
+ 1, s
->maxval
);
89 if (s
->T2
== 0 || reset_all
)
90 s
->T2
= iso_clip(FFMAX(3, basic_t2
/ factor
+ 5 * s
->near
),
92 if (s
->T3
== 0 || reset_all
)
93 s
->T3
= iso_clip(FFMAX(4, basic_t3
/ factor
+ 7 * s
->near
),
97 if (s
->reset
== 0 || reset_all
)
99 av_dlog(NULL
, "[JPEG-LS RESET] T=%i,%i,%i\n", s
->T1
, s
->T2
, s
->T3
);