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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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* VC-1 and WMV3 parser
*/
#include "parser.h"
#include "vc1.h"
#include "get_bits.h"
typedef struct {
ParseContext pc;
VC1Context v;
} VC1ParseContext;
static void vc1_extract_headers(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t *buf, int buf_size)
{
VC1ParseContext *vpc = s->priv_data;
GetBitContext gb;
const uint8_t *start, *end, *next;
uint8_t *buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
vpc->v.s.avctx = avctx;
vpc->v.parse_only = 1;
next = buf;
for(start = buf, end = buf + buf_size; next < end; start = next){
int buf2_size, size;
next = find_next_marker(start + 4, end);
size = next - start - 4;
buf2_size = vc1_unescape_buffer(start + 4, size, buf2);
init_get_bits(&gb, buf2, buf2_size * 8);
if(size <= 0) continue;
switch(AV_RB32(start)){
case VC1_CODE_SEQHDR:
vc1_decode_sequence_header(avctx, &vpc->v, &gb);
break;
case VC1_CODE_ENTRYPOINT:
vc1_decode_entry_point(avctx, &vpc->v, &gb);
break;
case VC1_CODE_FRAME:
if(vpc->v.profile < PROFILE_ADVANCED)
vc1_parse_frame_header (&vpc->v, &gb);
else
vc1_parse_frame_header_adv(&vpc->v, &gb);
/* keep AV_PICTURE_TYPE_BI internal to VC1 */
if (vpc->v.s.pict_type == AV_PICTURE_TYPE_BI)
s->pict_type = AV_PICTURE_TYPE_B;
else
s->pict_type = vpc->v.s.pict_type;
break;
}
}
av_free(buf2);
}
/**
* 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)
{
VC1ParseContext *vpc = s->priv_data;
int next;
if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
next= buf_size;
}else{
next= vc1_find_frame_end(&vpc->pc, buf, buf_size);
if (ff_combine_frame(&vpc->pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
}
vc1_extract_headers(s, avctx, buf, 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;
int charged=0;
for(i=0; i<buf_size; i++){
state= (state<<8) | buf[i];
if(IS_MARKER(state)){
if(state == VC1_CODE_SEQHDR || state == VC1_CODE_ENTRYPOINT){
charged=1;
}else if(charged){
return i-3;
}
}
}
return 0;
}
AVCodecParser ff_vc1_parser = {
{ CODEC_ID_VC1 },
sizeof(VC1ParseContext),
NULL,
vc1_parse,
ff_parse1_close,
vc1_split,
};
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