FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/subtitles.h
Date: 2024-11-20 23:03:26
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1 /*
2 * Copyright (c) 2012 Clément Bœsch
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #ifndef AVFORMAT_SUBTITLES_H
22 #define AVFORMAT_SUBTITLES_H
23
24 #include <stdint.h>
25 #include <stddef.h>
26 #include "avformat.h"
27 #include "libavutil/bprint.h"
28 #include "avio_internal.h"
29
30 enum sub_sort {
31 SUB_SORT_TS_POS = 0, ///< sort by timestamps, then position
32 SUB_SORT_POS_TS, ///< sort by position, then timestamps
33 };
34
35 enum ff_utf_type {
36 FF_UTF_8, // or other 8 bit encodings
37 FF_UTF16LE,
38 FF_UTF16BE,
39 };
40
41 typedef struct {
42 int type;
43 AVIOContext *pb;
44 unsigned char buf[8];
45 int buf_pos, buf_len;
46 FFIOContext buf_pb;
47 } FFTextReader;
48
49 /**
50 * Initialize the FFTextReader from the given AVIOContext. This function will
51 * read some bytes from pb, and test for UTF-8 or UTF-16 BOMs. Further accesses
52 * to FFTextReader will read more data from pb.
53 * If s is not NULL, the user will be warned if a UTF-16 conversion takes place.
54 *
55 * The purpose of FFTextReader is to transparently convert read data to UTF-8
56 * if the stream had a UTF-16 BOM.
57 *
58 * @param s Pointer to provide av_log context
59 * @param r object which will be initialized
60 * @param pb stream to read from (referenced as long as FFTextReader is in use)
61 */
62 void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb);
63
64 /**
65 * Similar to ff_text_init_avio(), but sets it up to read from a bounded buffer.
66 *
67 * @param r object which will be initialized
68 * @param buf buffer to read from (referenced as long as FFTextReader is in use)
69 * @param size size of buf
70 */
71 void ff_text_init_buf(FFTextReader *r, const void *buf, size_t size);
72
73 /**
74 * Return the byte position of the next byte returned by ff_text_r8(). For
75 * UTF-16 source streams, this will return the original position, but it will
76 * be incorrect if a codepoint was only partially read with ff_text_r8().
77 */
78 int64_t ff_text_pos(FFTextReader *r);
79
80 /**
81 * Return the next byte. The return value is always 0 - 255. Returns 0 on EOF.
82 * If the source stream is UTF-16, this reads from the stream converted to
83 * UTF-8. On invalid UTF-16, 0 is returned.
84 */
85 int ff_text_r8(FFTextReader *r);
86
87 /**
88 * Return non-zero if EOF was reached.
89 */
90 int ff_text_eof(FFTextReader *r);
91
92 /**
93 * Like ff_text_r8(), but don't remove the byte from the buffer.
94 */
95 int ff_text_peek_r8(FFTextReader *r);
96
97 /**
98 * Read the given number of bytes (in UTF-8). On error or EOF, \0 bytes are
99 * written.
100 */
101 void ff_text_read(FFTextReader *r, char *buf, size_t size);
102
103 typedef struct {
104 AVPacket **subs; ///< array of subtitles packets
105 int nb_subs; ///< number of subtitles packets
106 int allocated_size; ///< allocated size for subs
107 int current_sub_idx; ///< current position for the read packet callback
108 enum sub_sort sort; ///< sort method to use when finalizing subtitles
109 int keep_duplicates; ///< set to 1 to keep duplicated subtitle events
110 } FFDemuxSubtitlesQueue;
111
112 /**
113 * Insert a new subtitle event.
114 *
115 * @param event the subtitle line (not zero terminated) or NULL on not yet available event
116 * @param len the length of the event (in strlen() sense, so without '\0')
117 * @param merge set to 1 if the current event should be concatenated with the
118 * previous one instead of adding a new entry, 0 otherwise
119 */
120 AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
121 const uint8_t *event, size_t len, int merge);
122
123 /**
124 * Same as ff_subtitles_queue_insert but takes an AVBPrint input.
125 * Avoids common errors like handling incomplete AVBPrint.
126 */
127 AVPacket *ff_subtitles_queue_insert_bprint(FFDemuxSubtitlesQueue *q,
128 const AVBPrint *event, int merge);
129 /**
130 * Set missing durations, sort subtitles by PTS (and then byte position), and
131 * drop duplicated events.
132 */
133 void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q);
134
135 /**
136 * Generic read_packet() callback for subtitles demuxers using this queue
137 * system.
138 */
139 int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt);
140
141 /**
142 * Update current_sub_idx to emulate a seek. Except the first parameter, it
143 * matches FFInputFormat->read_seek2 prototypes.
144 */
145 int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
146 int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
147
148 /**
149 * Remove and destroy all the subtitles packets.
150 */
151 void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q);
152
153 int ff_subtitles_read_packet(AVFormatContext *s, AVPacket *pkt);
154
155 int ff_subtitles_read_seek(AVFormatContext *s, int stream_index,
156 int64_t min_ts, int64_t ts, int64_t max_ts, int flags);
157
158 int ff_subtitles_read_close(AVFormatContext *s);
159
160 /**
161 * SMIL helper to load next chunk ("<...>" or untagged content) in buf.
162 *
163 * @param c cached character, to avoid a backward seek
164 * @return size of chunk or error, e.g. AVERROR(ENOMEM) on incomplete buf
165 */
166 int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c);
167
168 /**
169 * SMIL helper to point on the value of an attribute in the given tag.
170 *
171 * @param s SMIL tag ("<...>")
172 * @param attr the attribute to look for
173 */
174 const char *ff_smil_get_attr_ptr(const char *s, const char *attr);
175
176 /**
177 * @brief Same as ff_subtitles_read_text_chunk(), but read from an AVIOContext.
178 */
179 av_warn_unused_result
180 int ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
181
182 /**
183 * @brief Read a subtitles chunk from FFTextReader.
184 *
185 * A chunk is defined by a multiline "event", ending with a second line break.
186 * The trailing line breaks are trimmed. CRLF are supported.
187 * Example: "foo\r\nbar\r\n\r\nnext" will print "foo\r\nbar" into buf, and pb
188 * will focus on the 'n' of the "next" string.
189 *
190 * @param tr I/O context
191 * @param buf an initialized buf where the chunk is written
192 * @return 0 on success, error value otherwise, e.g. AVERROR(ENOMEM) if buf is incomplete
193 *
194 * @note buf is cleared before writing into it.
195 */
196 av_warn_unused_result
197 int ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf);
198
199 /**
200 * Get the number of characters to increment to jump to the next line, or to
201 * the end of the string.
202 * The function handles the following line breaks schemes:
203 * LF, CRLF (MS), or standalone CR (old MacOS).
204 */
205 17856 static av_always_inline int ff_subtitles_next_line(const char *ptr)
206 {
207 17856 int n = strcspn(ptr, "\r\n");
208 17856 ptr += n;
209
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 20360 while (*ptr == '\r') {
210 2504 ptr++;
211 2504 n++;
212 }
213
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 17856 if (*ptr == '\n')
214 3798 n++;
215 17856 return n;
216 }
217
218 /**
219 * Read a line of text. Discards line ending characters.
220 * The function handles the following line breaks schemes:
221 * LF, CRLF (MS), or standalone CR (old MacOS).
222 *
223 * Returns the number of bytes written to buf. Always writes a terminating 0,
224 * similar as with snprintf.
225 *
226 * @note returns a negative error code if a \0 byte is found
227 */
228 ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size);
229
230 #endif /* AVFORMAT_SUBTITLES_H */
231