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 #ifndef AVCODEC_JPEGLS_H
29 #define AVCODEC_JPEGLS_H
30
31 #include "libavutil/common.h"
32 #include "avcodec.h"
33 #include "internal.h"
34
35 #undef near /* This file uses struct member 'near' which in windows.h is defined as empty. */
36
37 typedef struct JLSState {
38 int T1, T2, T3;
39 int A[367], B[367], C[365], N[367];
40 int limit, reset, bpp, qbpp, maxval, range;
41 int near, twonear;
42 int run_index[4];
43 } JLSState;
44
45 /**
46 * Calculate initial JPEG-LS parameters
47 */
48 void ff_jpegls_init_state(JLSState *state);
49
50 /**
51 * Calculate quantized gradient value, used for context determination
52 */
ff_jpegls_quantize(JLSState * s,int v)53 static inline int ff_jpegls_quantize(JLSState *s, int v)
54 {
55 if (v == 0)
56 return 0;
57 if (v < 0) {
58 if (v <= -s->T3)
59 return -4;
60 if (v <= -s->T2)
61 return -3;
62 if (v <= -s->T1)
63 return -2;
64 if (v < -s->near)
65 return -1;
66 return 0;
67 } else {
68 if (v <= s->near)
69 return 0;
70 if (v < s->T1)
71 return 1;
72 if (v < s->T2)
73 return 2;
74 if (v < s->T3)
75 return 3;
76 return 4;
77 }
78 }
79
80 /**
81 * Calculate JPEG-LS codec values
82 */
83 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
84
ff_jpegls_downscale_state(JLSState * state,int Q)85 static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
86 {
87 if (state->N[Q] == state->reset) {
88 state->A[Q] >>= 1;
89 state->B[Q] >>= 1;
90 state->N[Q] >>= 1;
91 }
92 state->N[Q]++;
93 }
94
ff_jpegls_update_state_regular(JLSState * state,int Q,int err)95 static inline int ff_jpegls_update_state_regular(JLSState *state,
96 int Q, int err)
97 {
98 if(FFABS(err) > 0xFFFF || FFABS(err) > INT_MAX - state->A[Q])
99 return -0x10000;
100 state->A[Q] += FFABS(err);
101 err *= state->twonear;
102 state->B[Q] += err;
103
104 ff_jpegls_downscale_state(state, Q);
105
106 if (state->B[Q] <= -state->N[Q]) {
107 state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
108 if (state->C[Q] > -128)
109 state->C[Q]--;
110 } else if (state->B[Q] > 0) {
111 state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
112 if (state->C[Q] < 127)
113 state->C[Q]++;
114 }
115
116 return err;
117 }
118
119 #define R(a, i) (bits == 8 ? ((uint8_t *)(a))[i] : ((uint16_t *)(a))[i])
120 #define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
121
122 #endif /* AVCODEC_JPEGLS_H */
123