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/*
* Dirac parser
*
* Copyright (c) 2007 Marco Gerards <marco@gnu.org>
*
* 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 dirac_parser.c
* Dirac Parser
* @author Marco Gerards <marco@gnu.org>
*/
#include "parser.h"
#define DIRAC_PARSE_INFO_PREFIX 0x42424344
/**
* 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 find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
{
uint32_t state = pc->state;
int i;
for (i = 0; i < buf_size; i++) {
state = (state << 8) | buf[i];
if (state == DIRAC_PARSE_INFO_PREFIX) {
pc->frame_start_found ^= 1;
if (!pc->frame_start_found) {
pc->state = -1;
return i - 3;
}
}
}
pc->state = state;
return END_NOT_FOUND;
}
static int dirac_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 = 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;
}
AVCodecParser dirac_parser = {
{ CODEC_ID_DIRAC },
sizeof(ParseContext),
NULL,
dirac_parse,
ff_parse_close,
};