mirror of
https://git.videolan.org/git/ffmpeg.git
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181 lines
4.8 KiB
C
181 lines
4.8 KiB
C
/*
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* DVB subtitle parser for Libav
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* Copyright (c) 2005 Ian Caulfield
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "avcodec.h"
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#include "dsputil.h"
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#include "get_bits.h"
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/* Parser (mostly) copied from dvdsub.c */
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#define PARSE_BUF_SIZE (65536)
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/* parser definition */
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typedef struct DVBSubParseContext {
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uint8_t *packet_buf;
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int packet_start;
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int packet_index;
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int in_packet;
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} DVBSubParseContext;
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static av_cold int dvbsub_parse_init(AVCodecParserContext *s)
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{
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DVBSubParseContext *pc = s->priv_data;
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pc->packet_buf = av_malloc(PARSE_BUF_SIZE);
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return 0;
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}
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static int dvbsub_parse(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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DVBSubParseContext *pc = s->priv_data;
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uint8_t *p, *p_end;
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int i, len, buf_pos = 0;
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av_dlog(avctx, "DVB parse packet pts=%"PRIx64", lpts=%"PRIx64", cpts=%"PRIx64":\n",
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s->pts, s->last_pts, s->cur_frame_pts[s->cur_frame_start_index]);
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for (i=0; i < buf_size; i++)
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{
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av_dlog(avctx, "%02x ", buf[i]);
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if (i % 16 == 15)
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av_dlog(avctx, "\n");
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}
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if (i % 16 != 0)
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av_dlog(avctx, "\n");
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*poutbuf = NULL;
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*poutbuf_size = 0;
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s->fetch_timestamp = 1;
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if (s->last_pts != s->pts && s->pts != AV_NOPTS_VALUE) /* Start of a new packet */
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{
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if (pc->packet_index != pc->packet_start)
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{
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av_dlog(avctx, "Discarding %d bytes\n",
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pc->packet_index - pc->packet_start);
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}
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pc->packet_start = 0;
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pc->packet_index = 0;
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if (buf_size < 2 || buf[0] != 0x20 || buf[1] != 0x00) {
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av_dlog(avctx, "Bad packet header\n");
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return -1;
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}
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buf_pos = 2;
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pc->in_packet = 1;
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} else {
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if (pc->packet_start != 0)
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{
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if (pc->packet_index != pc->packet_start)
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{
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memmove(pc->packet_buf, pc->packet_buf + pc->packet_start,
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pc->packet_index - pc->packet_start);
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pc->packet_index -= pc->packet_start;
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pc->packet_start = 0;
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} else {
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pc->packet_start = 0;
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pc->packet_index = 0;
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}
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}
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}
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if (buf_size - buf_pos + pc->packet_index > PARSE_BUF_SIZE)
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return -1;
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/* if not currently in a packet, discard data */
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if (pc->in_packet == 0)
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return buf_size;
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memcpy(pc->packet_buf + pc->packet_index, buf + buf_pos, buf_size - buf_pos);
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pc->packet_index += buf_size - buf_pos;
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p = pc->packet_buf;
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p_end = pc->packet_buf + pc->packet_index;
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while (p < p_end)
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{
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if (*p == 0x0f)
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{
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if (p + 6 <= p_end)
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{
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len = AV_RB16(p + 4);
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if (p + len + 6 <= p_end)
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{
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*poutbuf_size += len + 6;
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p += len + 6;
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} else
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break;
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} else
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break;
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} else if (*p == 0xff) {
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if (p + 1 < p_end)
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{
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av_dlog(avctx, "Junk at end of packet\n");
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}
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pc->packet_index = p - pc->packet_buf;
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pc->in_packet = 0;
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break;
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} else {
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av_log(avctx, AV_LOG_ERROR, "Junk in packet\n");
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pc->packet_index = p - pc->packet_buf;
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pc->in_packet = 0;
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break;
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}
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}
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if (*poutbuf_size > 0)
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{
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*poutbuf = pc->packet_buf;
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pc->packet_start = *poutbuf_size;
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}
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if (s->pts == AV_NOPTS_VALUE)
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s->pts = s->last_pts;
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return buf_size;
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}
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static av_cold void dvbsub_parse_close(AVCodecParserContext *s)
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{
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DVBSubParseContext *pc = s->priv_data;
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av_freep(&pc->packet_buf);
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}
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AVCodecParser ff_dvbsub_parser = {
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.codec_ids = { CODEC_ID_DVB_SUBTITLE },
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.priv_data_size = sizeof(DVBSubParseContext),
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.parser_init = dvbsub_parse_init,
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.parser_parse = dvbsub_parse,
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.parser_close = dvbsub_parse_close,
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};
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