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119 lines
2.7 KiB
119 lines
2.7 KiB
/* |
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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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