mirror of
https://git.ffmpeg.org/ffmpeg.git
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120 lines
2.7 KiB
C
120 lines
2.7 KiB
C
/*
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* MQ-coder encoder
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* Copyright (c) 2007 Kamil Nowosad
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* MQ-coder encoder
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* @file
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* @author Kamil Nowosad
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*/
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#include "mqc.h"
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static void byteout(MqcState *mqc)
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{
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retry:
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if (*mqc->bp == 0xff){
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mqc->bp++;
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*mqc->bp = mqc->c >> 20;
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mqc->c &= 0xfffff;
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mqc->ct = 7;
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} else if ((mqc->c & 0x8000000)){
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(*mqc->bp)++;
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mqc->c &= 0x7ffffff;
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goto retry;
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} else{
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mqc->bp++;
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*mqc->bp = mqc->c >> 19;
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mqc->c &= 0x7ffff;
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mqc->ct = 8;
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}
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}
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static void renorme(MqcState *mqc)
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{
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do{
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mqc->a += mqc->a;
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mqc->c += mqc->c;
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if (!--mqc->ct)
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byteout(mqc);
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} while (!(mqc->a & 0x8000));
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}
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static void setbits(MqcState *mqc)
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{
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int tmp = mqc->c + mqc->a;
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mqc->c |= 0xffff;
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if (mqc->c >= tmp)
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mqc->c -= 0x8000;
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}
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void ff_mqc_initenc(MqcState *mqc, uint8_t *bp)
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{
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ff_mqc_init_contexts(mqc);
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mqc->a = 0x8000;
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mqc->c = 0;
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mqc->bp = bp-1;
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mqc->bpstart = bp;
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mqc->ct = 12 + (*mqc->bp == 0xff);
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}
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void ff_mqc_encode(MqcState *mqc, uint8_t *cxstate, int d)
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{
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int qe;
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qe = ff_mqc_qe[*cxstate];
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mqc->a -= qe;
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if ((*cxstate & 1) == d){
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if (!(mqc->a & 0x8000)){
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if (mqc->a < qe)
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mqc->a = qe;
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else
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mqc->c += qe;
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*cxstate = ff_mqc_nmps[*cxstate];
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renorme(mqc);
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} else
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mqc->c += qe;
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} else{
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if (mqc->a < qe)
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mqc->c += qe;
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else
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mqc->a = qe;
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*cxstate = ff_mqc_nlps[*cxstate];
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renorme(mqc);
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}
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}
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int ff_mqc_length(MqcState *mqc)
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{
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return mqc->bp - mqc->bpstart;
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}
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int ff_mqc_flush(MqcState *mqc)
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{
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setbits(mqc);
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mqc->c = mqc->c << mqc->ct;
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byteout(mqc);
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mqc->c = mqc->c << mqc->ct;
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byteout(mqc);
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if (*mqc->bp != 0xff)
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mqc->bp++;
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return mqc->bp - mqc->bpstart;
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}
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