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 libavcodec/jpegls.h
25 * JPEG-LS common code.
26 */
27
28#ifndef AVCODEC_JPEGLS_H
29#define AVCODEC_JPEGLS_H
30
31#include "avcodec.h"
32
33typedef struct JpeglsContext{
34    AVCodecContext *avctx;
35    AVFrame picture;
36}JpeglsContext;
37
38typedef struct JLSState{
39    int T1, T2, T3;
40    int A[367], B[367], C[365], N[367];
41    int limit, reset, bpp, qbpp, maxval, range;
42    int near, twonear;
43    int run_index[3];
44}JLSState;
45
46extern const uint8_t ff_log2_run[32];
47
48/**
49 * Calculate initial JPEG-LS parameters
50 */
51void ff_jpegls_init_state(JLSState *state);
52
53/**
54 * Calculate quantized gradient value, used for context determination
55 */
56static inline int ff_jpegls_quantize(JLSState *s, int v){ //FIXME optimize
57    if(v==0) return 0;
58    if(v < 0){
59        if(v <= -s->T3) return -4;
60        if(v <= -s->T2) return -3;
61        if(v <= -s->T1) return -2;
62        if(v <  -s->near) return -1;
63        return 0;
64    }else{
65        if(v <= s->near) return 0;
66        if(v <  s->T1) return 1;
67        if(v <  s->T2) return 2;
68        if(v <  s->T3) return 3;
69        return 4;
70    }
71}
72
73/**
74 * Calculate JPEG-LS codec values
75 */
76void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
77
78
79static inline void ff_jpegls_downscale_state(JLSState *state, int Q){
80    if(state->N[Q] == state->reset){
81        state->A[Q] >>=1;
82        state->B[Q] >>=1;
83        state->N[Q] >>=1;
84    }
85    state->N[Q]++;
86}
87
88static inline int ff_jpegls_update_state_regular(JLSState *state, int Q, int err){
89    state->A[Q] += FFABS(err);
90    err *= state->twonear;
91    state->B[Q] += err;
92
93    ff_jpegls_downscale_state(state, Q);
94
95    if(state->B[Q] <= -state->N[Q]) {
96        state->B[Q]= FFMAX(state->B[Q] + state->N[Q], 1-state->N[Q]);
97        if(state->C[Q] > -128)
98            state->C[Q]--;
99    }else if(state->B[Q] > 0){
100        state->B[Q]= FFMIN(state->B[Q] - state->N[Q], 0);
101        if(state->C[Q] < 127)
102            state->C[Q]++;
103    }
104
105    return err;
106}
107
108#define R(a, i   ) (bits == 8 ?  ((uint8_t*)(a))[i]    :  ((uint16_t*)(a))[i]  )
109#define W(a, i, v) (bits == 8 ? (((uint8_t*)(a))[i]=v) : (((uint16_t*)(a))[i]=v))
110
111#endif /* AVCODEC_JPEGLS_H */
112