ffmpeg/libavformat/subtitles.h

119 lines
3.8 KiB
C

/*
* Copyright (c) 2012 Clément Bœsch
*
* 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
*/
#ifndef AVFORMAT_SUBTITLES_H
#define AVFORMAT_SUBTITLES_H
#include <stdint.h>
#include "avformat.h"
#include "libavutil/bprint.h"
typedef struct {
AVPacket *subs; ///< array of subtitles packets
int nb_subs; ///< number of subtitles packets
int allocated_size; ///< allocated size for subs
int current_sub_idx; ///< current position for the read packet callback
} FFDemuxSubtitlesQueue;
/**
* Insert a new subtitle event.
*
* @param event the subtitle line, may not be zero terminated
* @param len the length of the event (in strlen() sense, so without '\0')
* @param merge set to 1 if the current event should be concatenated with the
* previous one instead of adding a new entry, 0 otherwise
*/
AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
const uint8_t *event, int len, int merge);
/**
* Set missing durations and sort subtitles by PTS, and then byte position.
*/
void ff_subtitles_queue_finalize(FFDemuxSubtitlesQueue *q);
/**
* Generic read_packet() callback for subtitles demuxers using this queue
* system.
*/
int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt);
/**
* Update current_sub_idx to emulate a seek. Except the first parameter, it
* matches AVInputFormat->read_seek2 prototypes.
*/
int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
/**
* Remove and destroy all the subtitles packets.
*/
void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q);
/**
* SMIL helper to load next chunk ("<...>" or untagged content) in buf.
*
* @param c cached character, to avoid a backward seek
*/
int ff_smil_extract_next_chunk(AVIOContext *pb, AVBPrint *buf, char *c);
/**
* SMIL helper to point on the value of an attribute in the given tag.
*
* @param s SMIL tag ("<...>")
* @param attr the attribute to look for
*/
const char *ff_smil_get_attr_ptr(const char *s, const char *attr);
/**
* @brief Read a subtitles chunk.
*
* A chunk is defined by a multiline "event", ending with a second line break.
* The trailing line breaks are trimmed. CRLF are supported.
* Example: "foo\r\nbar\r\n\r\nnext" will print "foo\r\nbar" into buf, and pb
* will focus on the 'n' of the "next" string.
*
* @param pb I/O context
* @param buf an initialized buf where the chunk is written
*
* @note buf is cleared before writing into it.
*/
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
/**
* Get the number of characters to increment to jump to the next line, or to
* the end of the string.
* The function handles the following line breaks schemes: LF (any sane
* system), CRLF (MS), or standalone CR (old MacOS).
*/
static av_always_inline int ff_subtitles_next_line(const char *ptr)
{
int n = strcspn(ptr, "\r\n");
ptr += n;
if (*ptr == '\r') {
ptr++;
n++;
}
if (*ptr == '\n')
n++;
return n;
}
#endif /* AVFORMAT_SUBTITLES_H */