mirror of https://git.ffmpeg.org/ffmpeg.git
91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
|
|
* H261 parser
|
|
* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
|
|
* Copyright (c) 2004 Maarten Daniels
|
|
*
|
|
* 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 h261_parser.c
|
|
* h261codec.
|
|
*/
|
|
|
|
#include "parser.h"
|
|
|
|
|
|
static int h261_find_frame_end(ParseContext *pc, AVCodecContext* avctx, const uint8_t *buf, int buf_size){
|
|
int vop_found, i, j;
|
|
uint32_t state;
|
|
|
|
vop_found= pc->frame_start_found;
|
|
state= pc->state;
|
|
|
|
for(i=0; i<buf_size && !vop_found; i++){
|
|
state= (state<<8) | buf[i];
|
|
for(j=0; j<8; j++){
|
|
if(((state>>j)&0xFFFFF) == 0x00010){
|
|
vop_found=1;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if(vop_found){
|
|
for(; i<buf_size; i++){
|
|
state= (state<<8) | buf[i];
|
|
for(j=0; j<8; j++){
|
|
if(((state>>j)&0xFFFFF) == 0x00010){
|
|
pc->frame_start_found=0;
|
|
pc->state= state>>(2*8);
|
|
return i-1;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
pc->frame_start_found= vop_found;
|
|
pc->state= state;
|
|
return END_NOT_FOUND;
|
|
}
|
|
|
|
static int h261_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;
|
|
|
|
next= h261_find_frame_end(pc,avctx, 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;
|
|
}
|
|
|
|
AVCodecParser h261_parser = {
|
|
{ CODEC_ID_H261 },
|
|
sizeof(ParseContext),
|
|
NULL,
|
|
h261_parse,
|
|
ff_parse_close,
|
|
};
|