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path: root/libavformat/subtitles.c (plain)
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1/*
2 * Copyright (c) 2012-2013 Clément Bœsch <u pkh me>
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#include "avformat.h"
22#include "subtitles.h"
23#include "avio_internal.h"
24#include "libavutil/avassert.h"
25#include "libavutil/avstring.h"
26
27void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb)
28{
29 int i;
30 r->pb = pb;
31 r->buf_pos = r->buf_len = 0;
32 r->type = FF_UTF_8;
33 for (i = 0; i < 2; i++)
34 r->buf[r->buf_len++] = avio_r8(r->pb);
35 if (strncmp("\xFF\xFE", r->buf, 2) == 0) {
36 r->type = FF_UTF16LE;
37 r->buf_pos += 2;
38 } else if (strncmp("\xFE\xFF", r->buf, 2) == 0) {
39 r->type = FF_UTF16BE;
40 r->buf_pos += 2;
41 } else {
42 r->buf[r->buf_len++] = avio_r8(r->pb);
43 if (strncmp("\xEF\xBB\xBF", r->buf, 3) == 0) {
44 // UTF8
45 r->buf_pos += 3;
46 }
47 }
48 if (s && (r->type == FF_UTF16LE || r->type == FF_UTF16BE))
49 av_log(s, AV_LOG_INFO,
50 "UTF16 is automatically converted to UTF8, do not specify a character encoding\n");
51}
52
53void ff_text_init_buf(FFTextReader *r, void *buf, size_t size)
54{
55 memset(&r->buf_pb, 0, sizeof(r->buf_pb));
56 ffio_init_context(&r->buf_pb, buf, size, 0, NULL, NULL, NULL, NULL);
57 ff_text_init_avio(NULL, r, &r->buf_pb);
58}
59
60int64_t ff_text_pos(FFTextReader *r)
61{
62 return avio_tell(r->pb) - r->buf_len + r->buf_pos;
63}
64
65int ff_text_r8(FFTextReader *r)
66{
67 uint32_t val;
68 uint8_t tmp;
69 if (r->buf_pos < r->buf_len)
70 return r->buf[r->buf_pos++];
71 if (r->type == FF_UTF16LE) {
72 GET_UTF16(val, avio_rl16(r->pb), return 0;)
73 } else if (r->type == FF_UTF16BE) {
74 GET_UTF16(val, avio_rb16(r->pb), return 0;)
75 } else {
76 return avio_r8(r->pb);
77 }
78 if (!val)
79 return 0;
80 r->buf_pos = 0;
81 r->buf_len = 0;
82 PUT_UTF8(val, tmp, r->buf[r->buf_len++] = tmp;)
83 return r->buf[r->buf_pos++]; // buf_len is at least 1
84}
85
86void ff_text_read(FFTextReader *r, char *buf, size_t size)
87{
88 for ( ; size > 0; size--)
89 *buf++ = ff_text_r8(r);
90}
91
92int ff_text_eof(FFTextReader *r)
93{
94 return r->buf_pos >= r->buf_len && avio_feof(r->pb);
95}
96
97int ff_text_peek_r8(FFTextReader *r)
98{
99 int c;
100 if (r->buf_pos < r->buf_len)
101 return r->buf[r->buf_pos];
102 c = ff_text_r8(r);
103 if (!avio_feof(r->pb)) {
104 r->buf_pos = 0;
105 r->buf_len = 1;
106 r->buf[0] = c;
107 }
108 return c;
109}
110
111AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q,
112 const uint8_t *event, size_t len, int merge)
113{
114 AVPacket *subs, *sub;
115
116 if (merge && q->nb_subs > 0) {
117 /* merge with previous event */
118
119 int old_len;
120 sub = &q->subs[q->nb_subs - 1];
121 old_len = sub->size;
122 if (av_grow_packet(sub, len) < 0)
123 return NULL;
124 memcpy(sub->data + old_len, event, len);
125 } else {
126 /* new event */
127
128 if (q->nb_subs >= INT_MAX/sizeof(*q->subs) - 1)
129 return NULL;
130 subs = av_fast_realloc(q->subs, &q->allocated_size,
131 (q->nb_subs + 1) * sizeof(*q->subs));
132 if (!subs)
133 return NULL;
134 q->subs = subs;
135 sub = &subs[q->nb_subs++];
136 if (av_new_packet(sub, len) < 0)
137 return NULL;
138 sub->flags |= AV_PKT_FLAG_KEY;
139 sub->pts = sub->dts = 0;
140 memcpy(sub->data, event, len);
141 }
142 return sub;
143}
144
145static int cmp_pkt_sub_ts_pos(const void *a, const void *b)
146{
147 const AVPacket *s1 = a;
148 const AVPacket *s2 = b;
149 if (s1->pts == s2->pts)
150 return FFDIFFSIGN(s1->pos, s2->pos);
151 return FFDIFFSIGN(s1->pts , s2->pts);
152}
153
154static int cmp_pkt_sub_pos_ts(const void *a, const void *b)
155{
156 const AVPacket *s1 = a;
157 const AVPacket *s2 = b;
158 if (s1->pos == s2->pos) {
159 if (s1->pts == s2->pts)
160 return 0;
161 return s1->pts > s2->pts ? 1 : -1;
162 }
163 return s1->pos > s2->pos ? 1 : -1;
164}
165
166static void drop_dups(void *log_ctx, FFDemuxSubtitlesQueue *q)
167{
168 int i, drop = 0;
169
170 for (i = 1; i < q->nb_subs; i++) {
171 const int last_id = i - 1 - drop;
172 const AVPacket *last = &q->subs[last_id];
173
174 if (q->subs[i].pts == last->pts &&
175 q->subs[i].duration == last->duration &&
176 q->subs[i].stream_index == last->stream_index &&
177 !strcmp(q->subs[i].data, last->data)) {
178
179 av_packet_unref(&q->subs[i]);
180 drop++;
181 } else if (drop) {
182 q->subs[last_id + 1] = q->subs[i];
183 memset(&q->subs[i], 0, sizeof(q->subs[i])); // for safety
184 }
185 }
186
187 if (drop) {
188 q->nb_subs -= drop;
189 av_log(log_ctx, AV_LOG_WARNING, "Dropping %d duplicated subtitle events\n", drop);
190 }
191}
192
193void ff_subtitles_queue_finalize(void *log_ctx, FFDemuxSubtitlesQueue *q)
194{
195 int i;
196
197 qsort(q->subs, q->nb_subs, sizeof(*q->subs),
198 q->sort == SUB_SORT_TS_POS ? cmp_pkt_sub_ts_pos
199 : cmp_pkt_sub_pos_ts);
200 for (i = 0; i < q->nb_subs; i++)
201 if (q->subs[i].duration < 0 && i < q->nb_subs - 1)
202 q->subs[i].duration = q->subs[i + 1].pts - q->subs[i].pts;
203
204 if (!q->keep_duplicates)
205 drop_dups(log_ctx, q);
206}
207
208int ff_subtitles_queue_read_packet(FFDemuxSubtitlesQueue *q, AVPacket *pkt)
209{
210 AVPacket *sub = q->subs + q->current_sub_idx;
211
212 if (q->current_sub_idx == q->nb_subs)
213 return AVERROR_EOF;
214 if (av_copy_packet(pkt, sub) < 0) {
215 return AVERROR(ENOMEM);
216 }
217
218 pkt->dts = pkt->pts;
219 q->current_sub_idx++;
220 return 0;
221}
222
223static int search_sub_ts(const FFDemuxSubtitlesQueue *q, int64_t ts)
224{
225 int s1 = 0, s2 = q->nb_subs - 1;
226
227 if (s2 < s1)
228 return AVERROR(ERANGE);
229
230 for (;;) {
231 int mid;
232
233 if (s1 == s2)
234 return s1;
235 if (s1 == s2 - 1)
236 return q->subs[s1].pts <= q->subs[s2].pts ? s1 : s2;
237 mid = (s1 + s2) / 2;
238 if (q->subs[mid].pts <= ts)
239 s1 = mid;
240 else
241 s2 = mid;
242 }
243}
244
245int ff_subtitles_queue_seek(FFDemuxSubtitlesQueue *q, AVFormatContext *s, int stream_index,
246 int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
247{
248 if (flags & AVSEEK_FLAG_BYTE) {
249 return AVERROR(ENOSYS);
250 } else if (flags & AVSEEK_FLAG_FRAME) {
251 if (ts < 0 || ts >= q->nb_subs)
252 return AVERROR(ERANGE);
253 q->current_sub_idx = ts;
254 } else {
255 int i, idx = search_sub_ts(q, ts);
256 int64_t ts_selected;
257
258 if (idx < 0)
259 return idx;
260 for (i = idx; i < q->nb_subs && q->subs[i].pts < min_ts; i++)
261 if (stream_index == -1 || q->subs[i].stream_index == stream_index)
262 idx = i;
263 for (i = idx; i > 0 && q->subs[i].pts > max_ts; i--)
264 if (stream_index == -1 || q->subs[i].stream_index == stream_index)
265 idx = i;
266
267 ts_selected = q->subs[idx].pts;
268 if (ts_selected < min_ts || ts_selected > max_ts)
269 return AVERROR(ERANGE);
270
271 /* look back in the latest subtitles for overlapping subtitles */
272 for (i = idx - 1; i >= 0; i--) {
273 int64_t pts = q->subs[i].pts;
274 if (q->subs[i].duration <= 0 ||
275 (stream_index != -1 && q->subs[i].stream_index != stream_index))
276 continue;
277 if (pts >= min_ts && pts > ts_selected - q->subs[i].duration)
278 idx = i;
279 else
280 break;
281 }
282
283 /* If the queue is used to store multiple subtitles streams (like with
284 * VobSub) and the stream index is not specified, we need to make sure
285 * to focus on the smallest file position offset for a same timestamp;
286 * queue is ordered by pts and then filepos, so we can take the first
287 * entry for a given timestamp. */
288 if (stream_index == -1)
289 while (idx > 0 && q->subs[idx - 1].pts == q->subs[idx].pts)
290 idx--;
291
292 q->current_sub_idx = idx;
293 }
294 return 0;
295}
296
297void ff_subtitles_queue_clean(FFDemuxSubtitlesQueue *q)
298{
299 int i;
300
301 for (i = 0; i < q->nb_subs; i++)
302 av_packet_unref(&q->subs[i]);
303 av_freep(&q->subs);
304 q->nb_subs = q->allocated_size = q->current_sub_idx = 0;
305}
306
307int ff_smil_extract_next_text_chunk(FFTextReader *tr, AVBPrint *buf, char *c)
308{
309 int i = 0;
310 char end_chr;
311
312 if (!*c) // cached char?
313 *c = ff_text_r8(tr);
314 if (!*c)
315 return 0;
316
317 end_chr = *c == '<' ? '>' : '<';
318 do {
319 av_bprint_chars(buf, *c, 1);
320 *c = ff_text_r8(tr);
321 i++;
322 } while (*c != end_chr && *c);
323 if (end_chr == '>') {
324 av_bprint_chars(buf, '>', 1);
325 *c = 0;
326 }
327 return i;
328}
329
330const char *ff_smil_get_attr_ptr(const char *s, const char *attr)
331{
332 int in_quotes = 0;
333 const size_t len = strlen(attr);
334
335 while (*s) {
336 while (*s) {
337 if (!in_quotes && av_isspace(*s))
338 break;
339 in_quotes ^= *s == '"'; // XXX: support escaping?
340 s++;
341 }
342 while (av_isspace(*s))
343 s++;
344 if (!av_strncasecmp(s, attr, len) && s[len] == '=')
345 return s + len + 1 + (s[len + 1] == '"');
346 }
347 return NULL;
348}
349
350static inline int is_eol(char c)
351{
352 return c == '\r' || c == '\n';
353}
354
355void ff_subtitles_read_text_chunk(FFTextReader *tr, AVBPrint *buf)
356{
357 char eol_buf[5], last_was_cr = 0;
358 int n = 0, i = 0, nb_eol = 0;
359
360 av_bprint_clear(buf);
361
362 for (;;) {
363 char c = ff_text_r8(tr);
364
365 if (!c)
366 break;
367
368 /* ignore all initial line breaks */
369 if (n == 0 && is_eol(c))
370 continue;
371
372 /* line break buffering: we don't want to add the trailing \r\n */
373 if (is_eol(c)) {
374 nb_eol += c == '\n' || last_was_cr;
375 if (nb_eol == 2)
376 break;
377 eol_buf[i++] = c;
378 if (i == sizeof(eol_buf) - 1)
379 break;
380 last_was_cr = c == '\r';
381 continue;
382 }
383
384 /* only one line break followed by data: we flush the line breaks
385 * buffer */
386 if (i) {
387 eol_buf[i] = 0;
388 av_bprintf(buf, "%s", eol_buf);
389 i = nb_eol = 0;
390 }
391
392 av_bprint_chars(buf, c, 1);
393 n++;
394 }
395}
396
397void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf)
398{
399 FFTextReader tr;
400 tr.buf_pos = tr.buf_len = 0;
401 tr.type = 0;
402 tr.pb = pb;
403 ff_subtitles_read_text_chunk(&tr, buf);
404}
405
406ptrdiff_t ff_subtitles_read_line(FFTextReader *tr, char *buf, size_t size)
407{
408 size_t cur = 0;
409 if (!size)
410 return 0;
411 while (cur + 1 < size) {
412 unsigned char c = ff_text_r8(tr);
413 if (!c)
414 return ff_text_eof(tr) ? cur : AVERROR_INVALIDDATA;
415 if (c == '\r' || c == '\n')
416 break;
417 buf[cur++] = c;
418 buf[cur] = '\0';
419 }
420 if (ff_text_peek_r8(tr) == '\r')
421 ff_text_r8(tr);
422 if (ff_text_peek_r8(tr) == '\n')
423 ff_text_r8(tr);
424 return cur;
425}
426
generated by cgit at 2024-05-18 01:37:22 (GMT)