jpegls.c
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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 #include "jpegls.h"
29 
31  int i;
32 
33  state->twonear = state->near * 2 + 1;
34  state->range = ((state->maxval + state->twonear - 1) / state->twonear) + 1;
35 
36  // QBPP = ceil(log2(RANGE))
37  for(state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++);
38 
39  state->bpp = FFMAX(av_log2(state->maxval)+1, 2);
40  state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp;
41 
42  for(i = 0; i < 367; i++) {
43  state->A[i] = FFMAX((state->range + 32) >> 6, 2);
44  state->N[i] = 1;
45  }
46 
47 }
48 
49 /**
50  * Custom value clipping function used in T1, T2, T3 calculation
51  */
52 static inline int iso_clip(int v, int vmin, int vmax){
53  if(v > vmax || v < vmin) return vmin;
54  else return v;
55 }
56 
58  const int basic_t1= 3;
59  const int basic_t2= 7;
60  const int basic_t3= 21;
61  int factor;
62 
63  if(s->maxval==0 || reset_all) s->maxval= (1 << s->bpp) - 1;
64 
65  if(s->maxval >=128){
66  factor= (FFMIN(s->maxval, 4095) + 128)>>8;
67 
68  if(s->T1==0 || reset_all)
69  s->T1= iso_clip(factor*(basic_t1-2) + 2 + 3*s->near, s->near+1, s->maxval);
70  if(s->T2==0 || reset_all)
71  s->T2= iso_clip(factor*(basic_t2-3) + 3 + 5*s->near, s->T1, s->maxval);
72  if(s->T3==0 || reset_all)
73  s->T3= iso_clip(factor*(basic_t3-4) + 4 + 7*s->near, s->T2, s->maxval);
74  }else{
75  factor= 256 / (s->maxval + 1);
76 
77  if(s->T1==0 || reset_all)
78  s->T1= iso_clip(FFMAX(2, basic_t1/factor + 3*s->near), s->near+1, s->maxval);
79  if(s->T2==0 || reset_all)
80  s->T2= iso_clip(FFMAX(3, basic_t2/factor + 5*s->near), s->T1, s->maxval);
81  if(s->T3==0 || reset_all)
82  s->T3= iso_clip(FFMAX(4, basic_t3/factor + 7*s->near), s->T2, s->maxval);
83  }
84 
85  if(s->reset==0 || reset_all) s->reset= 64;
86  av_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);
87 }
int reset
Definition: jpegls.h:42
float v
const char * s
Definition: avisynth_c.h:668
int T2
Definition: jpegls.h:40
int twonear
Definition: jpegls.h:43
av_dlog(ac->avr,"%d samples - audio_convert: %s to %s (%s)\n", len, av_get_sample_fmt_name(ac->in_fmt), av_get_sample_fmt_name(ac->out_fmt), use_generic?ac->func_descr_generic:ac->func_descr)
int limit
Definition: jpegls.h:42
int bpp
Definition: jpegls.h:42
int maxval
Definition: jpegls.h:42
static int iso_clip(int v, int vmin, int vmax)
Custom value clipping function used in T1, T2, T3 calculation.
Definition: jpegls.c:52
void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all)
Calculate JPEG-LS codec values.
Definition: jpegls.c:57
#define FFMAX(a, b)
Definition: common.h:56
int near
Definition: jpegls.h:43
#define FFMIN(a, b)
Definition: common.h:58
int qbpp
Definition: jpegls.h:42
NULL
Definition: eval.c:55
int A[367]
Definition: jpegls.h:41
JPEG-LS common code.
synthesis window for stochastic i
int T1
Definition: jpegls.h:40
int range
Definition: jpegls.h:42
int N[367]
Definition: jpegls.h:41
static const int factor[16]
Definition: vf_pp7.c:202
static uint32_t state
Definition: trasher.c:27
#define av_log2
Definition: intmath.h:89
int T3
Definition: jpegls.h:40
void ff_jpegls_init_state(JLSState *state)
Calculate initial JPEG-LS parameters.
Definition: jpegls.c:30