yading@10: /*
yading@10:  * JPEG-LS common code
yading@10:  * Copyright (c) 2003 Michael Niedermayer
yading@10:  * Copyright (c) 2006 Konstantin Shishkov
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * JPEG-LS common code.
yading@10:  */
yading@10: 
yading@10: #include "jpegls.h"
yading@10: 
yading@10: void ff_jpegls_init_state(JLSState *state){
yading@10:     int i;
yading@10: 
yading@10:     state->twonear = state->near * 2 + 1;
yading@10:     state->range = ((state->maxval + state->twonear - 1) / state->twonear) + 1;
yading@10: 
yading@10:     // QBPP = ceil(log2(RANGE))
yading@10:     for(state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++);
yading@10: 
yading@10:     state->bpp = FFMAX(av_log2(state->maxval)+1, 2);
yading@10:     state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp;
yading@10: 
yading@10:     for(i = 0; i < 367; i++) {
yading@10:         state->A[i] = FFMAX((state->range + 32) >> 6, 2);
yading@10:         state->N[i] = 1;
yading@10:     }
yading@10: 
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Custom value clipping function used in T1, T2, T3 calculation
yading@10:  */
yading@10: static inline int iso_clip(int v, int vmin, int vmax){
yading@10:     if(v > vmax || v < vmin) return vmin;
yading@10:     else                     return v;
yading@10: }
yading@10: 
yading@10: void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all){
yading@10:     const int basic_t1= 3;
yading@10:     const int basic_t2= 7;
yading@10:     const int basic_t3= 21;
yading@10:     int factor;
yading@10: 
yading@10:     if(s->maxval==0 || reset_all) s->maxval= (1 << s->bpp) - 1;
yading@10: 
yading@10:     if(s->maxval >=128){
yading@10:         factor= (FFMIN(s->maxval, 4095) + 128)>>8;
yading@10: 
yading@10:         if(s->T1==0     || reset_all)
yading@10:             s->T1= iso_clip(factor*(basic_t1-2) + 2 + 3*s->near, s->near+1, s->maxval);
yading@10:         if(s->T2==0     || reset_all)
yading@10:             s->T2= iso_clip(factor*(basic_t2-3) + 3 + 5*s->near, s->T1, s->maxval);
yading@10:         if(s->T3==0     || reset_all)
yading@10:             s->T3= iso_clip(factor*(basic_t3-4) + 4 + 7*s->near, s->T2, s->maxval);
yading@10:     }else{
yading@10:         factor= 256 / (s->maxval + 1);
yading@10: 
yading@10:         if(s->T1==0     || reset_all)
yading@10:             s->T1= iso_clip(FFMAX(2, basic_t1/factor + 3*s->near), s->near+1, s->maxval);
yading@10:         if(s->T2==0     || reset_all)
yading@10:             s->T2= iso_clip(FFMAX(3, basic_t2/factor + 5*s->near), s->T1, s->maxval);
yading@10:         if(s->T3==0     || reset_all)
yading@10:             s->T3= iso_clip(FFMAX(4, basic_t3/factor + 7*s->near), s->T2, s->maxval);
yading@10:     }
yading@10: 
yading@10:     if(s->reset==0  || reset_all) s->reset= 64;
yading@10:     av_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3);
yading@10: }