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 JpeglsContext {
38 AVCodecContext *avctx;
39 } JpeglsContext;
40
41 typedef struct JLSState {
42 int T1, T2, T3;
43 int A[367], B[367], C[365], N[367];
44 int limit, reset, bpp, qbpp, maxval, range;
45 int near, twonear;
46 int run_index[4];
47 } JLSState;
48
49 /**
50 * Calculate initial JPEG-LS parameters
51 */
52 void ff_jpegls_init_state(JLSState *state);
53
54 /**
55 * Calculate quantized gradient value, used for context determination
56 */
ff_jpegls_quantize(JLSState * s,int v)57 static inline int ff_jpegls_quantize(JLSState *s, int v)
58 {
59 if (v == 0)
60 return 0;
61 if (v < 0) {
62 if (v <= -s->T3)
63 return -4;
64 if (v <= -s->T2)
65 return -3;
66 if (v <= -s->T1)
67 return -2;
68 if (v < -s->near)
69 return -1;
70 return 0;
71 } else {
72 if (v <= s->near)
73 return 0;
74 if (v < s->T1)
75 return 1;
76 if (v < s->T2)
77 return 2;
78 if (v < s->T3)
79 return 3;
80 return 4;
81 }
82 }
83
84 /**
85 * Calculate JPEG-LS codec values
86 */
87 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
88
ff_jpegls_downscale_state(JLSState * state,int Q)89 static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
90 {
91 if (state->N[Q] == state->reset) {
92 state->A[Q] >>= 1;
93 state->B[Q] >>= 1;
94 state->N[Q] >>= 1;
95 }
96 state->N[Q]++;
97 }
98
ff_jpegls_update_state_regular(JLSState * state,int Q,int err)99 static inline int ff_jpegls_update_state_regular(JLSState *state,
100 int Q, int err)
101 {
102 if(FFABS(err) > 0xFFFF)
103 return -0x10000;
104 state->A[Q] += FFABS(err);
105 err *= state->twonear;
106 state->B[Q] += err;
107
108 ff_jpegls_downscale_state(state, Q);
109
110 if (state->B[Q] <= -state->N[Q]) {
111 state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
112 if (state->C[Q] > -128)
113 state->C[Q]--;
114 } else if (state->B[Q] > 0) {
115 state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
116 if (state->C[Q] < 127)
117 state->C[Q]++;
118 }
119
120 return err;
121 }
122
123 #define R(a, i) (bits == 8 ? ((uint8_t *)(a))[i] : ((uint16_t *)(a))[i])
124 #define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
125
126 #endif /* AVCODEC_JPEGLS_H */
127