/*
* 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 <stddef.h>
#include "avformat.h"
#include "libavutil/bprint.h"
enum sub_sort {
SUB_SORT_TS_POS = 0, ///< sort by timestamps, then position
SUB_SORT_POS_TS, ///< sort by position, then timestamps
};
enum ff_utf_type {
FF_UTF_8, // or other 8 bit encodings
FF_UTF16LE,
FF_UTF16BE,
};
typedef struct {
int type;
AVIOContext *pb;
unsigned char buf[8];
int buf_pos, buf_len;
AVIOContext buf_pb;
} FFTextReader;
/**
* Initialize the FFTextReader from the given AVIOContext. This function will
* read some bytes from pb, and test for UTF-8 or UTF-16 BOMs. Further accesses
* to FFTextReader will read more data from pb.
* If s is not NULL, the user will be warned if a UTF-16 conversion takes place.
*
* The purpose of FFTextReader is to transparently convert read data to UTF-8
* if the stream had a UTF-16 BOM.
*
* @param s Pointer to provide av_log context
* @param r object which will be initialized
* @param pb stream to read from (referenced as long as FFTextReader is in use)
*/
void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb);
/**
* Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
*
* @param r object which will be initialized
* @param buf buffer to read from (referenced as long as FFTextReader is in use)
* @param size size of buf
*/
void ff_text_init_buf(FFTextReader *r, void *buf, size_t size);
/**
* Return the byte position of the next byte returned by ff_text_r8(). For
* UTF-16 source streams, this will return the original position, but it will
* be incorrect if a codepoint was only partially read with ff_text_r8().
*/
int64_t ff_text_pos(FFTextReader *r);
/**
* Return the next byte. The return value is always 0 - 255. Returns 0 on EOF.
* If the source stream is UTF-16, this reads from the stream converted to
* UTF-8. On invalid UTF-16, 0 is returned.
*/
int ff_text_r8(FFTextReader *r);
/**
* Return non-zero if EOF was reached.
*/
int ff_text_eof(FFTextReader *r);
/**
* Like ff_text_r8(), but don't remove the byte from the buffer.
*/
int ff_text_peek_r8(FFTextReader *r);
/**
* Read the given number of bytes (in UTF-8). On error or EOF, \0 bytes are
* written.
*/
void ff_text_read(FFTextReader *r, char *buf, size_t size);
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
enum sub_sort sort; ///< sort method to use when finalizing subtitles
int keep_duplicates; ///< set to 1 to keep duplicated subtitle events
} 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, size_t len, int merge);
/**
* Set missing durations, sort subtitles by PTS (and then byte position), and
* drop duplicated events.
*/
void ff_subtitles_queue_finalize(void *log_ctx, 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_text_chunk(FFTextReader *tr, 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 Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
*/
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
/**
* @brief Read a subtitles chunk from FFTextReader.
*
* 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 tr 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_text_chunk(FFTextReader *tr, 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, 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;
}
/**
* Read a line of text. Discards line ending characters.
* The function handles the following line breaks schemes:
* LF, CRLF (MS), or standalone CR (old MacOS).
*
* Returns the number of bytes written to buf. Always writes a terminating 0,
* similar as with snprintf.
*
* @note returns a negative error code if a \0 byte is found
*/
ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size);
#endif /* AVFORMAT_SUBTITLES_H */