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/*
* 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 "avcodec.h"
#include "dsputil.h"
#include "bitstream.h"
//#define DEBUG
//#define DEBUG_PACKET_CONTENTS
/* Parser (mostly) copied from dvdsub.c */
#define PARSE_BUF_SIZE (65536)
/* parser definition */
typedef struct DVBSubParseContext {
uint8_t *packet_buf;
int packet_start;
int packet_index;
int in_packet;
} DVBSubParseContext;
static int dvbsub_parse_init(AVCodecParserContext *s)
{
DVBSubParseContext *pc = s->priv_data;
pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
return 0;
}
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 len, buf_pos = 0;
#ifdef DEBUG
av_log(avctx, AV_LOG_INFO, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
#endif
#ifdef DEBUG_PACKET_CONTENTS
int i;
for (i=0; i < buf_size; i++)
{
av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]);
if (i % 16 == 15)
av_log(avctx, AV_LOG_INFO, "\n");
}
if (i % 16 != 0)
av_log(avctx, AV_LOG_INFO, "\n");
#endif
*poutbuf = NULL;
*poutbuf_size = 0;
s->fetch_timestamp = 1;
if (s->last_pts != s->pts && s->last_pts != AV_NOPTS_VALUE) /* Start of a new packet */
{
if (pc->packet_index != pc->packet_start)
{
#ifdef DEBUG
av_log(avctx, AV_LOG_INFO, "Discarding %d bytes\n",
pc->packet_index - pc->packet_start);
#endif
}
pc->packet_start = 0;
pc->packet_index = 0;
if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
#ifdef DEBUG
av_log(avctx, AV_LOG_INFO, "Bad packet header\n");
#endif
return -1;
}
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 -1;
/* if not currently in a packet, discard 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 (p + 6 <= p_end)
{
len = AV_RB16(p + 4);
if (p + len + 6 <= p_end)
{
*poutbuf_size += len + 6;
p += len + 6;
} else
break;
} else
break;
} else if (*p == 0xff) {
if (p + 1 < p_end)
{
#ifdef DEBUG
av_log(avctx, AV_LOG_INFO, "Junk at end of packet\n");
#endif
}
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 (*poutbuf_size > 0)
{
*poutbuf = pc->packet_buf;
pc->packet_start = *poutbuf_size;
}
if (s->last_pts == AV_NOPTS_VALUE)
s->last_pts = s->pts;
return buf_size;
}
static void dvbsub_parse_close(AVCodecParserContext *s)
{
DVBSubParseContext *pc = s->priv_data;
av_freep(&pc->packet_buf);
}
AVCodecParser dvbsub_parser = {
{ CODEC_ID_DVB_SUBTITLE },
sizeof(DVBSubParseContext),
dvbsub_parse_init,
dvbsub_parse,
dvbsub_parse_close,
};
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