/* * JPEG-LS common code * Copyright (c) 2003 Michael Niedermayer * Copyright (c) 2006 Konstantin Shishkov * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * JPEG-LS common code. */ #include <stddef.h> #include "libavutil/internal.h" #include "libavutil/intmath.h" #include "jpegls.h" void ff_jpegls_init_state(JLSState *state) { int i; state->twonear = state->near * 2 + 1; state->range = (state->maxval + state->twonear - 1) / state->twonear + 1; // QBPP = ceil(log2(RANGE)) for (state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++) ; state->bpp = FFMAX(av_log2(state->maxval) + 1, 2); state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp; for (i = 0; i < 367; i++) { state->A[i] = FFMAX(state->range + 32 >> 6, 2); state->N[i] = 1; } } /** * Custom value clipping function used in T1, T2, T3 calculation */ static inline int iso_clip(int v, int vmin, int vmax) { if (v > vmax || v < vmin) return vmin; else return v; } void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all) { const int basic_t1 = 3; const int basic_t2 = 7; const int basic_t3 = 21; int factor; if (s->maxval == 0 || reset_all) s->maxval = (1 << s->bpp) - 1; if (s->maxval >= 128) { factor = FFMIN(s->maxval, 4095) + 128 >> 8; if (s->T1 == 0 || reset_all) s->T1 = iso_clip(factor * (basic_t1 - 2) + 2 + 3 * s->near, s->near + 1, s->maxval); if (s->T2 == 0 || reset_all) s->T2 = iso_clip(factor * (basic_t2 - 3) + 3 + 5 * s->near, s->T1, s->maxval); if (s->T3 == 0 || reset_all) s->T3 = iso_clip(factor * (basic_t3 - 4) + 4 + 7 * s->near, s->T2, s->maxval); } else { factor = 256 / (s->maxval + 1); if (s->T1 == 0 || reset_all) s->T1 = iso_clip(FFMAX(2, basic_t1 / factor + 3 * s->near), s->near + 1, s->maxval); if (s->T2 == 0 || reset_all) s->T2 = iso_clip(FFMAX(3, basic_t2 / factor + 5 * s->near), s->T1, s->maxval); if (s->T3 == 0 || reset_all) s->T3 = iso_clip(FFMAX(4, basic_t3 / factor + 7 * s->near), s->T2, s->maxval); } if (s->reset == 0 || reset_all) s->reset = 64; ff_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3); }