| /* |
| * 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 libavcodec/jpegls.c |
| * JPEG-LS common code. |
| */ |
| |
| #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++); |
| |
| if(state->bpp < 8) |
| state->limit = 16 + 2 * state->bpp - state->qbpp; |
| else |
| state->limit = (4 * state->bpp) - 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; |
| // av_log(NULL, AV_LOG_DEBUG, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3); |
| } |