libavcodec/jpegls.h

   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
  33 typedef struct JpeglsContext{
  34     AVCodecContext *avctx;
  35     AVFrame picture;
  36 }JpeglsContext;
  37
  38 typedef 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
  46 extern const uint8_t ff_log2_run[32];
  47
  48 /**
  49  * Calculate initial JPEG-LS parameters
  50  */
  51 void ff_jpegls_init_state(JLSState *state);
  52
  53 /**
  54  * Calculate quantized gradient value, used for context determination
  55  */
  56 static 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  */
  76 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
  77
  78
  79 static 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
  88 static 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 */