FFmpeg
jpegls.h
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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 <limits.h>
32 #include "libavutil/common.h"
33 
34 #undef near /* This file uses struct member 'near' which in windows.h is defined as empty. */
35 
36 typedef struct JLSState {
37  int T1, T2, T3;
38  int A[367], B[367], C[365], N[367];
40  int near, twonear;
41  int run_index[4];
42 } JLSState;
43 
44 /**
45  * Calculate initial JPEG-LS parameters
46  */
48 
49 /**
50  * Calculate quantized gradient value, used for context determination
51  */
52 static inline int ff_jpegls_quantize(JLSState *s, int v)
53 {
54  if (v == 0)
55  return 0;
56  if (v < 0) {
57  if (v <= -s->T3)
58  return -4;
59  if (v <= -s->T2)
60  return -3;
61  if (v <= -s->T1)
62  return -2;
63  if (v < -s->near)
64  return -1;
65  return 0;
66  } else {
67  if (v <= s->near)
68  return 0;
69  if (v < s->T1)
70  return 1;
71  if (v < s->T2)
72  return 2;
73  if (v < s->T3)
74  return 3;
75  return 4;
76  }
77 }
78 
79 /**
80  * Calculate JPEG-LS codec values
81  */
82 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
83 
84 static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
85 {
86  if (state->N[Q] == state->reset) {
87  state->A[Q] >>= 1;
88  state->B[Q] >>= 1;
89  state->N[Q] >>= 1;
90  }
91  state->N[Q]++;
92 }
93 
95  int Q, int err)
96 {
97  if(FFABS(err) > 0xFFFF || FFABS(err) > INT_MAX - state->A[Q])
98  return -0x10000;
99  state->A[Q] += FFABS(err);
100  err *= state->twonear;
101  state->B[Q] += err;
102 
104 
105  if (state->B[Q] <= -state->N[Q]) {
106  state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
107  if (state->C[Q] > -128)
108  state->C[Q]--;
109  } else if (state->B[Q] > 0) {
110  state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
111  if (state->C[Q] < 127)
112  state->C[Q]++;
113  }
114 
115  return err;
116 }
117 
118 #define R(a, i) (bits == 8 ? ((uint8_t *)(a))[i] : ((uint16_t *)(a))[i])
119 #define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
120 
121 #endif /* AVCODEC_JPEGLS_H */
JLSState::bpp
int bpp
Definition: jpegls.h:39
ff_jpegls_reset_coding_parameters
void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all)
Calculate JPEG-LS codec values.
Definition: jpegls.c:64
JLSState::T1
int T1
Definition: jpegls.h:37
FFMAX
#define FFMAX(a, b)
Definition: macros.h:47
JLSState::T2
int T2
Definition: jpegls.h:37
JLSState::run_index
int run_index[4]
Definition: jpegls.h:41
JLSState::B
int B[367]
Definition: jpegls.h:38
JLSState
Definition: jpegls.h:36
s
#define s(width, name)
Definition: cbs_vp9.c:257
limits.h
JLSState::maxval
int maxval
Definition: jpegls.h:39
FFABS
#define FFABS(a)
Absolute value, Note, INT_MIN / INT64_MIN result in undefined behavior as they are not representable ...
Definition: common.h:65
JLSState::near
int near
Definition: jpegls.h:40
ff_jpegls_downscale_state
static void ff_jpegls_downscale_state(JLSState *state, int Q)
Definition: jpegls.h:84
JLSState::A
int A[367]
Definition: jpegls.h:38
state
static struct @317 state
JLSState::range
int range
Definition: jpegls.h:39
JLSState::T3
int T3
Definition: jpegls.h:37
JLSState::twonear
int twonear
Definition: jpegls.h:40
JLSState::reset
int reset
Definition: jpegls.h:39
ff_jpegls_quantize
static int ff_jpegls_quantize(JLSState *s, int v)
Calculate quantized gradient value, used for context determination.
Definition: jpegls.h:52
ff_jpegls_update_state_regular
static int ff_jpegls_update_state_regular(JLSState *state, int Q, int err)
Definition: jpegls.h:94
common.h
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
JLSState::qbpp
int qbpp
Definition: jpegls.h:39
JLSState::C
int C[365]
Definition: jpegls.h:38
ff_jpegls_init_state
void ff_jpegls_init_state(JLSState *state)
Calculate initial JPEG-LS parameters.
Definition: jpegls.c:33
JLSState::N
int N[367]
Definition: jpegls.h:38
JLSState::limit
int limit
Definition: jpegls.h:39