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/*
* VC-1 and WMV3 parser
* Copyright (c) 2006-2007 Konstantin Shishkov
* Partly based on vc9.c (c) 2005 Anonymous, Alex Beregszaszi, Michael Niedermayer
*
* 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
*/
/**
* @file libavcodec/vc1_parser.c
* VC-1 and WMV3 parser
*/
#include "parser.h"
#include "vc1.h"
/**
* finds the end of the current frame in the bitstream.
* @return the position of the first byte of the next frame, or -1
*/
static int vc1_find_frame_end(ParseContext *pc, const uint8_t *buf,
int buf_size) {
int pic_found, i;
uint32_t state;
pic_found= pc->frame_start_found;
state= pc->state;
i=0;
if(!pic_found){
for(i=0; i<buf_size; i++){
state= (state<<8) | buf[i];
if(state == VC1_CODE_FRAME || state == VC1_CODE_FIELD){
i++;
pic_found=1;
break;
}
}
}
if(pic_found){
/* EOF considered as end of frame */
if (buf_size == 0)
return 0;
for(; i<buf_size; i++){
state= (state<<8) | buf[i];
if(IS_MARKER(state) && state != VC1_CODE_FIELD && state != VC1_CODE_SLICE){
pc->frame_start_found=0;
pc->state=-1;
return i-3;
}
}
}
pc->frame_start_found= pic_found;
pc->state= state;
return END_NOT_FOUND;
}
static int vc1_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
ParseContext *pc = s->priv_data;
int next;
if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
next= buf_size;
}else{
next= vc1_find_frame_end(pc, buf, buf_size);
if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
static int vc1_split(AVCodecContext *avctx,
const uint8_t *buf, int buf_size)
{
int i;
uint32_t state= -1;
for(i=0; i<buf_size; i++){
state= (state<<8) | buf[i];
if(IS_MARKER(state) && state != VC1_CODE_SEQHDR && state != VC1_CODE_ENTRYPOINT)
return i-3;
}
return 0;
}
AVCodecParser vc1_parser = {
{ CODEC_ID_VC1 },
sizeof(ParseContext1),
NULL,
vc1_parse,
ff_parse1_close,
vc1_split,
};
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