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.c 25 * JPEG-LS common code. 26 */ 27 28#include "jpegls.h" 29 30void ff_jpegls_init_state(JLSState *state){ 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 if(state->bpp < 8) 40 state->limit = 16 + 2 * state->bpp - state->qbpp; 41 else 42 state->limit = (4 * state->bpp) - state->qbpp; 43 44 for(i = 0; i < 367; i++) { 45 state->A[i] = FFMAX((state->range + 32) >> 6, 2); 46 state->N[i] = 1; 47 } 48 49} 50 51/** 52 * Custom value clipping function used in T1, T2, T3 calculation 53 */ 54static inline int iso_clip(int v, int vmin, int vmax){ 55 if(v > vmax || v < vmin) return vmin; 56 else return v; 57} 58 59void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all){ 60 const int basic_t1= 3; 61 const int basic_t2= 7; 62 const int basic_t3= 21; 63 int factor; 64 65 if(s->maxval==0 || reset_all) s->maxval= (1 << s->bpp) - 1; 66 67 if(s->maxval >=128){ 68 factor= (FFMIN(s->maxval, 4095) + 128)>>8; 69 70 if(s->T1==0 || reset_all) 71 s->T1= iso_clip(factor*(basic_t1-2) + 2 + 3*s->near, s->near+1, s->maxval); 72 if(s->T2==0 || reset_all) 73 s->T2= iso_clip(factor*(basic_t2-3) + 3 + 5*s->near, s->T1, s->maxval); 74 if(s->T3==0 || reset_all) 75 s->T3= iso_clip(factor*(basic_t3-4) + 4 + 7*s->near, s->T2, s->maxval); 76 }else{ 77 factor= 256 / (s->maxval + 1); 78 79 if(s->T1==0 || reset_all) 80 s->T1= iso_clip(FFMAX(2, basic_t1/factor + 3*s->near), s->near+1, s->maxval); 81 if(s->T2==0 || reset_all) 82 s->T2= iso_clip(FFMAX(3, basic_t2/factor + 5*s->near), s->T1, s->maxval); 83 if(s->T3==0 || reset_all) 84 s->T3= iso_clip(FFMAX(4, basic_t3/factor + 7*s->near), s->T2, s->maxval); 85 } 86 87 if(s->reset==0 || reset_all) s->reset= 64; 88// av_log(NULL, AV_LOG_DEBUG, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3); 89} 90