FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/tedcaptionsdec.c
Date: 2024-02-16 17:37:06
Exec Total Coverage
Lines: 9 203 4.4%
Functions: 1 14 7.1%
Branches: 7 138 5.1%

Line Branch Exec Source
1 /*
2 * TED Talks captions format decoder
3 * Copyright (c) 2012 Nicolas George
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavutil/bprint.h"
23 #include "libavutil/log.h"
24 #include "libavutil/opt.h"
25 #include "avformat.h"
26 #include "internal.h"
27 #include "subtitles.h"
28
29 typedef struct {
30 AVClass *class;
31 int64_t start_time;
32 FFDemuxSubtitlesQueue subs;
33 } TEDCaptionsDemuxer;
34
35 static const AVOption tedcaptions_options[] = {
36 { "start_time", "set the start time (offset) of the subtitles, in ms",
37 offsetof(TEDCaptionsDemuxer, start_time), AV_OPT_TYPE_INT64,
38 { .i64 = 15000 }, INT64_MIN, INT64_MAX,
39 AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM },
40 { NULL },
41 };
42
43 static const AVClass tedcaptions_demuxer_class = {
44 .class_name = "tedcaptions_demuxer",
45 .item_name = av_default_item_name,
46 .option = tedcaptions_options,
47 .version = LIBAVUTIL_VERSION_INT,
48 };
49
50 #define BETWEEN(a, amin, amax) ((unsigned)((a) - (amin)) <= (amax) - (amin))
51
52 #define HEX_DIGIT_TEST(c) (BETWEEN(c, '0', '9') || BETWEEN((c) | 32, 'a', 'z'))
53 #define HEX_DIGIT_VAL(c) ((c) <= '9' ? (c) - '0' : ((c) | 32) - 'a' + 10)
54 #define ERR_CODE(c) ((c) < 0 ? (c) : AVERROR_INVALIDDATA)
55
56 static void av_bprint_utf8(AVBPrint *bp, unsigned c)
57 {
58 int bytes, i;
59
60 if (c <= 0x7F) {
61 av_bprint_chars(bp, c, 1);
62 return;
63 }
64 bytes = (av_log2(c) - 2) / 5;
65 av_bprint_chars(bp, (c >> (bytes * 6)) | ((0xFF80 >> bytes) & 0xFF), 1);
66 for (i = bytes - 1; i >= 0; i--)
67 av_bprint_chars(bp, ((c >> (i * 6)) & 0x3F) | 0x80, 1);
68 }
69
70 static void next_byte(AVIOContext *pb, int *cur_byte)
71 {
72 uint8_t b;
73 int ret = avio_read(pb, &b, 1);
74 *cur_byte = ret > 0 ? b : ret == 0 ? AVERROR_EOF : ret;
75 }
76
77 static void skip_spaces(AVIOContext *pb, int *cur_byte)
78 {
79 while (*cur_byte == ' ' || *cur_byte == '\t' ||
80 *cur_byte == '\n' || *cur_byte == '\r')
81 next_byte(pb, cur_byte);
82 }
83
84 static int expect_byte(AVIOContext *pb, int *cur_byte, uint8_t c)
85 {
86 skip_spaces(pb, cur_byte);
87 if (*cur_byte != c)
88 return ERR_CODE(*cur_byte);
89 next_byte(pb, cur_byte);
90 return 0;
91 }
92
93 static int parse_string(AVIOContext *pb, int *cur_byte, AVBPrint *bp, int full)
94 {
95 int ret;
96
97 ret = expect_byte(pb, cur_byte, '"');
98 if (ret < 0)
99 return ret;
100 while (*cur_byte > 0 && *cur_byte != '"') {
101 if (*cur_byte == '\\') {
102 next_byte(pb, cur_byte);
103 if (*cur_byte < 0)
104 return AVERROR_INVALIDDATA;
105 if ((*cur_byte | 32) == 'u') {
106 unsigned chr = 0, i;
107 for (i = 0; i < 4; i++) {
108 next_byte(pb, cur_byte);
109 if (!HEX_DIGIT_TEST(*cur_byte))
110 return ERR_CODE(*cur_byte);
111 chr = chr * 16 + HEX_DIGIT_VAL(*cur_byte);
112 }
113 av_bprint_utf8(bp, chr);
114 } else {
115 av_bprint_chars(bp, *cur_byte, 1);
116 }
117 } else {
118 av_bprint_chars(bp, *cur_byte, 1);
119 }
120 next_byte(pb, cur_byte);
121 }
122 ret = expect_byte(pb, cur_byte, '"');
123 if (ret < 0)
124 return ret;
125 if (full && !av_bprint_is_complete(bp))
126 return AVERROR(ENOMEM);
127
128 return 0;
129 }
130
131 static int parse_label(AVIOContext *pb, int *cur_byte, AVBPrint *bp)
132 {
133 int ret;
134
135 av_bprint_init(bp, 0, AV_BPRINT_SIZE_AUTOMATIC);
136 ret = parse_string(pb, cur_byte, bp, 0);
137 if (ret < 0)
138 return ret;
139 ret = expect_byte(pb, cur_byte, ':');
140 if (ret < 0)
141 return ret;
142 return 0;
143 }
144
145 static int parse_boolean(AVIOContext *pb, int *cur_byte, int *result)
146 {
147 static const char * const text[] = { "false", "true" };
148 const char *p;
149 int i;
150
151 skip_spaces(pb, cur_byte);
152 for (i = 0; i < 2; i++) {
153 p = text[i];
154 if (*cur_byte != *p)
155 continue;
156 for (; *p; p++, next_byte(pb, cur_byte))
157 if (*cur_byte != *p)
158 return AVERROR_INVALIDDATA;
159 if (BETWEEN(*cur_byte | 32, 'a', 'z'))
160 return AVERROR_INVALIDDATA;
161 *result = i;
162 return 0;
163 }
164 return AVERROR_INVALIDDATA;
165 }
166
167 static int parse_int(AVIOContext *pb, int *cur_byte, int64_t *result)
168 {
169 int64_t val = 0;
170
171 skip_spaces(pb, cur_byte);
172 if ((unsigned)*cur_byte - '0' > 9)
173 return AVERROR_INVALIDDATA;
174 while (BETWEEN(*cur_byte, '0', '9')) {
175 if (val > INT_MAX/10 - (*cur_byte - '0'))
176 return AVERROR_INVALIDDATA;
177 val = val * 10 + (*cur_byte - '0');
178 next_byte(pb, cur_byte);
179 }
180 *result = val;
181 return 0;
182 }
183
184 static int parse_file(AVIOContext *pb, FFDemuxSubtitlesQueue *subs)
185 {
186 int ret, cur_byte, start_of_par;
187 AVBPrint label, content;
188 int64_t pos, start, duration;
189 AVPacket *pkt;
190
191 av_bprint_init(&content, 0, AV_BPRINT_SIZE_UNLIMITED);
192
193 next_byte(pb, &cur_byte);
194 ret = expect_byte(pb, &cur_byte, '{');
195 if (ret < 0)
196 return AVERROR_INVALIDDATA;
197 ret = parse_label(pb, &cur_byte, &label);
198 if (ret < 0 || strcmp(label.str, "captions"))
199 return AVERROR_INVALIDDATA;
200 ret = expect_byte(pb, &cur_byte, '[');
201 if (ret < 0)
202 return AVERROR_INVALIDDATA;
203 while (1) {
204 start = duration = AV_NOPTS_VALUE;
205 ret = expect_byte(pb, &cur_byte, '{');
206 if (ret < 0)
207 goto fail;
208 pos = avio_tell(pb) - 1;
209 while (1) {
210 ret = parse_label(pb, &cur_byte, &label);
211 if (ret < 0)
212 goto fail;
213 if (!strcmp(label.str, "startOfParagraph")) {
214 ret = parse_boolean(pb, &cur_byte, &start_of_par);
215 if (ret < 0)
216 goto fail;
217 } else if (!strcmp(label.str, "content")) {
218 ret = parse_string(pb, &cur_byte, &content, 1);
219 if (ret < 0)
220 goto fail;
221 } else if (!strcmp(label.str, "startTime")) {
222 ret = parse_int(pb, &cur_byte, &start);
223 if (ret < 0)
224 goto fail;
225 } else if (!strcmp(label.str, "duration")) {
226 ret = parse_int(pb, &cur_byte, &duration);
227 if (ret < 0)
228 goto fail;
229 } else {
230 ret = AVERROR_INVALIDDATA;
231 goto fail;
232 }
233 skip_spaces(pb, &cur_byte);
234 if (cur_byte != ',')
235 break;
236 next_byte(pb, &cur_byte);
237 }
238 ret = expect_byte(pb, &cur_byte, '}');
239 if (ret < 0)
240 goto fail;
241
242 if (!content.size || start == AV_NOPTS_VALUE ||
243 duration == AV_NOPTS_VALUE) {
244 ret = AVERROR_INVALIDDATA;
245 goto fail;
246 }
247 pkt = ff_subtitles_queue_insert_bprint(subs, &content, 0);
248 if (!pkt) {
249 ret = AVERROR(ENOMEM);
250 goto fail;
251 }
252 pkt->pos = pos;
253 pkt->pts = start;
254 pkt->duration = duration;
255 av_bprint_clear(&content);
256
257 skip_spaces(pb, &cur_byte);
258 if (cur_byte != ',')
259 break;
260 next_byte(pb, &cur_byte);
261 }
262 ret = expect_byte(pb, &cur_byte, ']');
263 if (ret < 0)
264 goto fail;
265 ret = expect_byte(pb, &cur_byte, '}');
266 if (ret < 0)
267 goto fail;
268 skip_spaces(pb, &cur_byte);
269 if (cur_byte != AVERROR_EOF)
270 ret = ERR_CODE(cur_byte);
271 fail:
272 av_bprint_finalize(&content, NULL);
273 return ret;
274 }
275
276 static av_cold int tedcaptions_read_header(AVFormatContext *avf)
277 {
278 TEDCaptionsDemuxer *tc = avf->priv_data;
279 AVStream *st = avformat_new_stream(avf, NULL);
280 FFStream *sti;
281 int ret, i;
282 AVPacket *last;
283
284 if (!st)
285 return AVERROR(ENOMEM);
286
287 sti = ffstream(st);
288 ret = parse_file(avf->pb, &tc->subs);
289 if (ret < 0) {
290 if (ret == AVERROR_INVALIDDATA)
291 av_log(avf, AV_LOG_ERROR, "Syntax error near offset %"PRId64".\n",
292 avio_tell(avf->pb));
293 return ret;
294 }
295 ff_subtitles_queue_finalize(avf, &tc->subs);
296 for (i = 0; i < tc->subs.nb_subs; i++)
297 tc->subs.subs[i]->pts += tc->start_time;
298
299 last = tc->subs.subs[tc->subs.nb_subs - 1];
300 st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
301 st->codecpar->codec_id = AV_CODEC_ID_TEXT;
302 avpriv_set_pts_info(st, 64, 1, 1000);
303 sti->probe_packets = 0;
304 st->start_time = 0;
305 st->duration = last->pts + last->duration;
306 sti->cur_dts = 0;
307
308 return 0;
309 }
310
311 static int tedcaptions_read_packet(AVFormatContext *avf, AVPacket *packet)
312 {
313 TEDCaptionsDemuxer *tc = avf->priv_data;
314
315 return ff_subtitles_queue_read_packet(&tc->subs, packet);
316 }
317
318 static int tedcaptions_read_close(AVFormatContext *avf)
319 {
320 TEDCaptionsDemuxer *tc = avf->priv_data;
321
322 ff_subtitles_queue_clean(&tc->subs);
323 return 0;
324 }
325
326 7023 static av_cold int tedcaptions_read_probe(const AVProbeData *p)
327 {
328 static const char *const tags[] = {
329 "\"captions\"", "\"duration\"", "\"content\"",
330 "\"startOfParagraph\"", "\"startTime\"",
331 };
332 7023 unsigned i, count = 0;
333 const char *t;
334
335
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7023 if (p->buf[strspn(p->buf, " \t\r\n")] != '{')
336 7020 return 0;
337
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18 for (i = 0; i < FF_ARRAY_ELEMS(tags); i++) {
338
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15 if (!(t = strstr(p->buf, tags[i])))
339 15 continue;
340 t += strlen(tags[i]);
341 t += strspn(t, " \t\r\n");
342 if (*t == ':')
343 count++;
344 }
345
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6 return count == FF_ARRAY_ELEMS(tags) ? AVPROBE_SCORE_MAX :
346
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3 count ? AVPROBE_SCORE_EXTENSION : 0;
347 }
348
349 static int tedcaptions_read_seek(AVFormatContext *avf, int stream_index,
350 int64_t min_ts, int64_t ts, int64_t max_ts,
351 int flags)
352 {
353 TEDCaptionsDemuxer *tc = avf->priv_data;
354 return ff_subtitles_queue_seek(&tc->subs, avf, stream_index,
355 min_ts, ts, max_ts, flags);
356 }
357
358 const AVInputFormat ff_tedcaptions_demuxer = {
359 .name = "tedcaptions",
360 .long_name = NULL_IF_CONFIG_SMALL("TED Talks captions"),
361 .priv_data_size = sizeof(TEDCaptionsDemuxer),
362 .flags_internal = FF_FMT_INIT_CLEANUP,
363 .priv_class = &tedcaptions_demuxer_class,
364 .read_header = tedcaptions_read_header,
365 .read_packet = tedcaptions_read_packet,
366 .read_close = tedcaptions_read_close,
367 .read_probe = tedcaptions_read_probe,
368 .read_seek2 = tedcaptions_read_seek,
369 };
370