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