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 Libav.
   7  *
   8  * Libav 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  * Libav 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 Libav; 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 "avcodec.h"
  32 #include "libavutil/common.h"
  33
  34 typedef struct JpeglsContext{
  35     AVCodecContext *avctx;
  36     AVFrame picture;
  37 }JpeglsContext;
  38
  39 typedef struct JLSState{
  40     int T1, T2, T3;
  41     int A[367], B[367], C[365], N[367];
  42     int limit, reset, bpp, qbpp, maxval, range;
  43     int near, twonear;
  44     int run_index[3];
  45 }JLSState;
  46
  47 extern const uint8_t ff_log2_run[32];
  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  */
  57 static inline int ff_jpegls_quantize(JLSState *s, int v){ //FIXME optimize
  58     if(v==0) return 0;
  59     if(v < 0){
  60         if(v <= -s->T3) return -4;
  61         if(v <= -s->T2) return -3;
  62         if(v <= -s->T1) return -2;
  63         if(v <  -s->near) return -1;
  64         return 0;
  65     }else{
  66         if(v <= s->near) return 0;
  67         if(v <  s->T1) return 1;
  68         if(v <  s->T2) return 2;
  69         if(v <  s->T3) return 3;
  70         return 4;
  71     }
  72 }
  73
  74 /**
  75  * Calculate JPEG-LS codec values
  76  */
  77 void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
  78
  79
  80 static inline void ff_jpegls_downscale_state(JLSState *state, int Q){
  81     if(state->N[Q] == state->reset){
  82         state->A[Q] >>=1;
  83         state->B[Q] >>=1;
  84         state->N[Q] >>=1;
  85     }
  86     state->N[Q]++;
  87 }
  88
  89 static inline int ff_jpegls_update_state_regular(JLSState *state, int Q, int err){
  90     state->A[Q] += FFABS(err);
  91     err *= state->twonear;
  92     state->B[Q] += err;
  93
  94     ff_jpegls_downscale_state(state, Q);
  95
  96     if(state->B[Q] <= -state->N[Q]) {
  97         state->B[Q]= FFMAX(state->B[Q] + state->N[Q], 1-state->N[Q]);
  98         if(state->C[Q] > -128)
  99             state->C[Q]--;
 100     }else if(state->B[Q] > 0){
 101         state->B[Q]= FFMIN(state->B[Q] - state->N[Q], 0);
 102         if(state->C[Q] < 127)
 103             state->C[Q]++;
 104     }
 105
 106     return err;
 107 }
 108
 109 #define R(a, i   ) (bits == 8 ?  ((uint8_t*)(a))[i]    :  ((uint16_t*)(a))[i]  )
 110 #define W(a, i, v) (bits == 8 ? (((uint8_t*)(a))[i]=v) : (((uint16_t*)(a))[i]=v))
 111
 112 #endif /* AVCODEC_JPEGLS_H */