/libavcodec/mqcenc.c
http://github.com/FFmpeg/FFmpeg · C · 139 lines · 103 code · 11 blank · 25 comment · 20 complexity · 82807a14b650b55de776cce46bbab6d6 MD5 · raw file
- /*
- * 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 "libavutil/avassert.h"
- #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;
- }
- int ff_mqc_flush_to(MqcState *mqc, uint8_t *dst, int *dst_len)
- {
- MqcState mqc2 = *mqc;
- mqc2.bpstart=
- mqc2.bp = dst;
- *mqc2.bp = *mqc->bp;
- ff_mqc_flush(&mqc2);
- *dst_len = mqc2.bp - dst;
- if (mqc->bp < mqc->bpstart) {
- av_assert1(mqc->bpstart - mqc->bp == 1);
- av_assert1(*dst_len > 0);
- av_assert1(mqc->bp[0] == 0 && dst[0] == 0);
- (*dst_len) --;
- memmove(dst, dst+1, *dst_len);
- return mqc->bp - mqc->bpstart + 1 + *dst_len;
- }
- return mqc->bp - mqc->bpstart + *dst_len;
- }