ffmpeg/libavcodec/dvbsub_parser.c

171 lines
4.5 KiB
C

/*
* DVB subtitle parser for FFmpeg
* Copyright (c) 2005 Ian Caulfield
*
* 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
*/
#include <inttypes.h>
#include <string.h>
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
/* Parser (mostly) copied from dvdsub.c */
#define PARSE_BUF_SIZE (65536)
/* parser definition */
typedef struct DVBSubParseContext {
int packet_start;
int packet_index;
int in_packet;
uint8_t packet_buf[PARSE_BUF_SIZE];
} DVBSubParseContext;
static int dvbsub_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
DVBSubParseContext *pc = s->priv_data;
uint8_t *p, *p_end;
int i, len, buf_pos = 0;
int out_size = 0;
ff_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
for (i=0; i < buf_size; i++)
{
ff_dlog(avctx, "%02x ", buf[i]);
if (i % 16 == 15)
ff_dlog(avctx, "\n");
}
if (i % 16 != 0)
ff_dlog(avctx, "\n");
*poutbuf = buf;
*poutbuf_size = buf_size;
s->fetch_timestamp = 1;
if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
{
if (pc->packet_index != pc->packet_start)
{
ff_dlog(avctx, "Discarding %d bytes\n",
pc->packet_index - pc->packet_start);
}
pc->packet_start = 0;
pc->packet_index = 0;
if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
ff_dlog(avctx, "Bad packet header\n");
return buf_size;
}
buf_pos = 2;
pc->in_packet = 1;
} else {
if (pc->packet_start != 0)
{
if (pc->packet_index != pc->packet_start)
{
memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
pc->packet_index - pc->packet_start);
pc->packet_index -= pc->packet_start;
pc->packet_start = 0;
} else {
pc->packet_start = 0;
pc->packet_index = 0;
}
}
}
if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
return buf_size;
/* if not currently in a packet, pass data */
if (pc->in_packet == 0)
return buf_size;
memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
pc->packet_index += buf_size - buf_pos;
p = pc->packet_buf;
p_end = pc->packet_buf + pc->packet_index;
while (p < p_end)
{
if (*p == 0x0f)
{
if (6 <= p_end - p)
{
len = AV_RB16(p + 4);
if (len + 6 <= p_end - p)
{
out_size += len + 6;
p += len + 6;
} else
break;
} else
break;
} else if (*p == 0xff) {
if (1 < p_end - p)
{
ff_dlog(avctx, "Junk at end of packet\n");
}
pc->packet_index = p - pc->packet_buf;
pc->in_packet = 0;
break;
} else {
av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
pc->packet_index = p - pc->packet_buf;
pc->in_packet = 0;
break;
}
}
if (out_size > 0)
{
*poutbuf = pc->packet_buf;
*poutbuf_size = out_size;
pc->packet_start = *poutbuf_size;
}
if (s->pts == AV_NOPTS_VALUE)
s->pts = s->last_pts;
return buf_size;
}
const AVCodecParser ff_dvbsub_parser = {
.codec_ids = { AV_CODEC_ID_DVB_SUBTITLE },
.priv_data_size = sizeof(DVBSubParseContext),
.parser_parse = dvbsub_parse,
};