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