yading@10: /*
yading@10:  * MQ-coder encoder
yading@10:  * Copyright (c) 2007 Kamil Nowosad
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:  * MQ-coder encoder
yading@10:  * @file
yading@10:  * @author Kamil Nowosad
yading@10:  */
yading@10: 
yading@10: #include "mqc.h"
yading@10: 
yading@10: static void byteout(MqcState *mqc)
yading@10: {
yading@10: retry:
yading@10:     if (*mqc->bp == 0xff){
yading@10:         mqc->bp++;
yading@10:         *mqc->bp = mqc->c >> 20;
yading@10:         mqc->c &= 0xfffff;
yading@10:         mqc->ct = 7;
yading@10:     } else if ((mqc->c & 0x8000000)){
yading@10:         (*mqc->bp)++;
yading@10:         mqc->c &= 0x7ffffff;
yading@10:         goto retry;
yading@10:     } else{
yading@10:         mqc->bp++;
yading@10:         *mqc->bp = mqc->c >> 19;
yading@10:         mqc->c &= 0x7ffff;
yading@10:         mqc->ct = 8;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void renorme(MqcState *mqc)
yading@10: {
yading@10:     do{
yading@10:         mqc->a += mqc->a;
yading@10:         mqc->c += mqc->c;
yading@10:         if (!--mqc->ct)
yading@10:             byteout(mqc);
yading@10:     } while (!(mqc->a & 0x8000));
yading@10: }
yading@10: 
yading@10: static void setbits(MqcState *mqc)
yading@10: {
yading@10:     int tmp = mqc->c + mqc->a;
yading@10:     mqc->c |= 0xffff;
yading@10:     if (mqc->c >= tmp)
yading@10:         mqc->c -= 0x8000;
yading@10: }
yading@10: 
yading@10: void ff_mqc_initenc(MqcState *mqc, uint8_t *bp)
yading@10: {
yading@10:     ff_mqc_init_contexts(mqc);
yading@10:     mqc->a = 0x8000;
yading@10:     mqc->c = 0;
yading@10:     mqc->bp = bp-1;
yading@10:     mqc->bpstart = bp;
yading@10:     mqc->ct = 12 + (*mqc->bp == 0xff);
yading@10: }
yading@10: 
yading@10: void ff_mqc_encode(MqcState *mqc, uint8_t *cxstate, int d)
yading@10: {
yading@10:     int qe;
yading@10: 
yading@10:     qe = ff_mqc_qe[*cxstate];
yading@10:     mqc->a -= qe;
yading@10:     if ((*cxstate & 1) == d){
yading@10:         if (!(mqc->a & 0x8000)){
yading@10:             if (mqc->a < qe)
yading@10:                 mqc->a = qe;
yading@10:             else
yading@10:                 mqc->c += qe;
yading@10:             *cxstate = ff_mqc_nmps[*cxstate];
yading@10:             renorme(mqc);
yading@10:         } else
yading@10:             mqc->c += qe;
yading@10:     } else{
yading@10:         if (mqc->a < qe)
yading@10:             mqc->c += qe;
yading@10:         else
yading@10:             mqc->a = qe;
yading@10:         *cxstate = ff_mqc_nlps[*cxstate];
yading@10:         renorme(mqc);
yading@10:     }
yading@10: }
yading@10: 
yading@10: int ff_mqc_length(MqcState *mqc)
yading@10: {
yading@10:     return mqc->bp - mqc->bpstart;
yading@10: }
yading@10: 
yading@10: int ff_mqc_flush(MqcState *mqc)
yading@10: {
yading@10:     setbits(mqc);
yading@10:     mqc->c = mqc->c << mqc->ct;
yading@10:     byteout(mqc);
yading@10:     mqc->c = mqc->c << mqc->ct;
yading@10:     byteout(mqc);
yading@10:     if (*mqc->bp != 0xff)
yading@10:         mqc->bp++;
yading@10:     return mqc->bp - mqc->bpstart;
yading@10: }