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Diffstat (limited to 'libavformat/subtitles.h')
-rw-r--r-- | libavformat/subtitles.h | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/libavformat/subtitles.h b/libavformat/subtitles.h new file mode 100644 index 0000000000..903c24d9df --- /dev/null +++ b/libavformat/subtitles.h @@ -0,0 +1,208 @@ +/* + * 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. + * + * The purpose of FFTextReader is to transparently convert read data to UTF-8 + * if the stream had a UTF-16 BOM. + * + * @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(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 +} 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_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 */ |