95 lines
2.8 KiB
C
95 lines
2.8 KiB
C
|
/*
|
||
|
|
* H.261 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
|
||
|
|
* H.261 parser
|
||
|
|
*/
|
||
|
|
|
||
|
|
#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) & 0xFFFFF0) == 0x000100) {
|
||
|
|
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) & 0xFFFFF0) == 0x000100) {
|
||
|
|
pc->frame_start_found = 0;
|
||
|
|
pc->state = (state >> (3 * 8)) + 0xFF00;
|
||
|
|
return i - 2;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
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;
|
||
|
|
|
||
|
|
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
|
||
|
|
next = buf_size;
|
||
|
|
} else {
|
||
|
|
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 ff_h261_parser = {
|
||
|
|
.codec_ids = { AV_CODEC_ID_H261 },
|
||
|
|
.priv_data_size = sizeof(ParseContext),
|
||
|
|
.parser_parse = h261_parse,
|
||
|
|
.parser_close = ff_parse_close,
|
||
|
|
};
|