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 30void ff_jpegls_init_state(JLSState *state) 31{ 32 int i; 33 34 state->twonear = state->near * 2 + 1; 35 state->range = (state->maxval + state->twonear - 1) / state->twonear + 1; 36 37 // QBPP = ceil(log2(RANGE)) 38 for (state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++) 39 ; 40 41 state->bpp = FFMAX(av_log2(state->maxval) + 1, 2); 42 state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - 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 * Custom value clipping function used in T1, T2, T3 calculation 52 */ 53static inline int iso_clip(int v, int vmin, int vmax) 54{ 55 if (v > vmax || v < vmin) 56 return vmin; 57 else 58 return v; 59} 60 61void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all) 62{ 63 const int basic_t1 = 3; 64 const int basic_t2 = 7; 65 const int basic_t3 = 21; 66 int factor; 67 68 if (s->maxval == 0 || reset_all) 69 s->maxval = (1 << s->bpp) - 1; 70 71 if (s->maxval >= 128) { 72 factor = FFMIN(s->maxval, 4095) + 128 >> 8; 73 74 if (s->T1 == 0 || reset_all) 75 s->T1 = iso_clip(factor * (basic_t1 - 2) + 2 + 3 * s->near, 76 s->near + 1, s->maxval); 77 if (s->T2 == 0 || reset_all) 78 s->T2 = iso_clip(factor * (basic_t2 - 3) + 3 + 5 * s->near, 79 s->T1, s->maxval); 80 if (s->T3 == 0 || reset_all) 81 s->T3 = iso_clip(factor * (basic_t3 - 4) + 4 + 7 * s->near, 82 s->T2, s->maxval); 83 } else { 84 factor = 256 / (s->maxval + 1); 85 86 if (s->T1 == 0 || reset_all) 87 s->T1 = iso_clip(FFMAX(2, basic_t1 / factor + 3 * s->near), 88 s->near + 1, s->maxval); 89 if (s->T2 == 0 || reset_all) 90 s->T2 = iso_clip(FFMAX(3, basic_t2 / factor + 5 * s->near), 91 s->T1, s->maxval); 92 if (s->T3 == 0 || reset_all) 93 s->T3 = iso_clip(FFMAX(4, basic_t3 / factor + 7 * s->near), 94 s->T2, s->maxval); 95 } 96 97 if (s->reset == 0 || reset_all) 98 s->reset = 64; 99 av_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3); 100} 101