summaryrefslogtreecommitdiffstats
path: root/sub/sd_srt.c
blob: 5c5cff52c45ecca99763de665b814076bf584168 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
/*
 * Subtitles converter to SSA/ASS in order to allow special formatting
 *
 * This file is part of mpv.
 *
 * mpv is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * mpv 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with mpv.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>
#include <strings.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdbool.h>

#include "common/common.h"
#include "common/msg.h"
#include "misc/bstr.h"
#include "misc/ctype.h"
#include "sd.h"

struct line {
    char *buf;
    int bufsize;
    int len;
};

#ifdef __GNUC__
static void append_text(struct line *dst, char *fmt, ...) __attribute__ ((format(printf, 2, 3)));
#endif

static void append_text(struct line *dst, char *fmt, ...)
{
    va_list va;
    va_start(va, fmt);
    int ret = vsnprintf(dst->buf + dst->len, dst->bufsize - dst->len, fmt, va);
    if (ret < 0)
        goto out;
    dst->len += ret;
    if (dst->len > dst->bufsize)
        dst->len = dst->bufsize;
 out:
    va_end(va);
}

static void append_text_n(struct line *dst, char *start, size_t length)
{
    append_text(dst, "%.*s", (int)length, start);
}


/*
 *      SubRip
 *
 *      Support basic tags (italic, bold, underline, strike-through)
 *      and font tag with size, color and face attributes.
 *
 */

struct font_tag {
    int size;
    uint32_t color;
    struct bstr face;
    bool has_size : 1;
    bool has_color : 1;
    bool has_face : 1;
};

static const struct tag_conv {
    char *from;
    char *to;
} subrip_basic_tags[] = {
    {"<i>", "{\\i1}"}, {"</i>", "{\\i0}"},
    {"<b>", "{\\b1}"}, {"</b>", "{\\b0}"},
    {"<u>", "{\\u1}"}, {"</u>", "{\\u0}"},
    {"<s>", "{\\s1}"}, {"</s>", "{\\s0}"},
    {"}", "\\}"},
    {"\r\n", "\\N"}, {"\n", "\\N"}, {"\r", "\\N"},
};

static const struct {
    char *s;
    uint32_t v;
} subrip_web_colors[] = {
    /* Named CSS3 colors in RGB format; a subset of those
       at http://www.w3.org/TR/css3-color/#svg-color */
    {"aliceblue",           0xF0F8FF},
    {"antiquewhite",        0xFAEBD7},
    {"aqua",                0x00FFFF},
    {"aquamarine",          0x7FFFD4},
    {"azure",               0xF0FFFF},
    {"beige",               0xF5F5DC},
    {"bisque",              0xFFE4C4},
    {"black",               0x000000},
    {"blanchedalmond",      0xFFEBCD},
    {"blue",                0x0000FF},
    {"blueviolet",          0x8A2BE2},
    {"brown",               0xA52A2A},
    {"burlywood",           0xDEB887},
    {"cadetblue",           0x5F9EA0},
    {"chartreuse",          0x7FFF00},
    {"chocolate",           0xD2691E},
    {"coral",               0xFF7F50},
    {"cornflowerblue",      0x6495ED},
    {"cornsilk",            0xFFF8DC},
    {"crimson",             0xDC143C},
    {"cyan",                0x00FFFF},
    {"darkblue",            0x00008B},
    {"darkcyan",            0x008B8B},
    {"darkgoldenrod",       0xB8860B},
    {"darkgray",            0xA9A9A9},
    {"darkgreen",           0x006400},
    {"darkgrey",            0xA9A9A9},
    {"darkkhaki",           0xBDB76B},
    {"darkmagenta",         0x8B008B},
    {"darkolivegreen",      0x556B2F},
    {"darkorange",          0xFF8C00},
    {"darkorchid",          0x9932CC},
    {"darkred",             0x8B0000},
    {"darksalmon",          0xE9967A},
    {"darkseagreen",        0x8FBC8F},
    {"darkslateblue",       0x483D8B},
    {"darkslategray",       0x2F4F4F},
    {"darkslategrey",       0x2F4F4F},
    {"darkturquoise",       0x00CED1},
    {"darkviolet",          0x9400D3},
    {"deeppink",            0xFF1493},
    {"deepskyblue",         0x00BFFF},
    {"dimgray",             0x696969},
    {"dimgrey",             0x696969},
    {"dodgerblue",          0x1E90FF},
    {"firebrick",           0xB22222},
    {"floralwhite",         0xFFFAF0},
    {"forestgreen",         0x228B22},
    {"fuchsia",             0xFF00FF},
    {"gainsboro",           0xDCDCDC},
    {"ghostwhite",          0xF8F8FF},
    {"gold",                0xFFD700},
    {"goldenrod",           0xDAA520},
    {"gray",                0x808080},
    {"green",               0x008000},
    {"greenyellow",         0xADFF2F},
    {"grey",                0x808080},
    {"honeydew",            0xF0FFF0},
    {"hotpink",             0xFF69B4},
    {"indianred",           0xCD5C5C},
    {"indigo",              0x4B0082},
    {"ivory",               0xFFFFF0},
    {"khaki",               0xF0E68C},
    {"lavender",            0xE6E6FA},
    {"lavenderblush",       0xFFF0F5},
    {"lawngreen",           0x7CFC00},
    {"lemonchiffon",        0xFFFACD},
    {"lightblue",           0xADD8E6},
    {"lightcoral",          0xF08080},
    {"lightcyan",           0xE0FFFF},
    {"lightgoldenrodyellow", 0xFAFAD2},
    {"lightgray",           0xD3D3D3},
    {"lightgreen",          0x90EE90},
    {"lightgrey",           0xD3D3D3},
    {"lightpink",           0xFFB6C1},
    {"lightsalmon",         0xFFA07A},
    {"lightseagreen",       0x20B2AA},
    {"lightskyblue",        0x87CEFA},
    {"lightslategray",      0x778899},
    {"lightslategrey",      0x778899},
    {"lightsteelblue",      0xB0C4DE},
    {"lightyellow",         0xFFFFE0},
    {"lime",                0x00FF00},
    {"limegreen",           0x32CD32},
    {"linen",               0xFAF0E6},
    {"magenta",             0xFF00FF},
    {"maroon",              0x800000},
    {"mediumaquamarine",    0x66CDAA},
    {"mediumblue",          0x0000CD},
    {"mediumorchid",        0xBA55D3},
    {"mediumpurple",        0x9370DB},
    {"mediumseagreen",      0x3CB371},
    {"mediumslateblue",     0x7B68EE},
    {"mediumspringgreen",   0x00FA9A},
    {"mediumturquoise",     0x48D1CC},
    {"mediumvioletred",     0xC71585},
    {"midnightblue",        0x191970},
    {"mintcream",           0xF5FFFA},
    {"mistyrose",           0xFFE4E1},
    {"moccasin",            0xFFE4B5},
    {"navajowhite",         0xFFDEAD},
    {"navy",                0x000080},
    {"oldlace",             0xFDF5E6},
    {"olive",               0x808000},
    {"olivedrab",           0x6B8E23},
    {"orange",              0xFFA500},
    {"orangered",           0xFF4500},
    {"orchid",              0xDA70D6},
    {"palegoldenrod",       0xEEE8AA},
    {"palegreen",           0x98FB98},
    {"paleturquoise",       0xAFEEEE},
    {"palevioletred",       0xDB7093},
    {"papayawhip",          0xFFEFD5},
    {"peachpuff",           0xFFDAB9},
    {"peru",                0xCD853F},
    {"pink",                0xFFC0CB},
    {"plum",                0xDDA0DD},
    {"powderblue",          0xB0E0E6},
    {"purple",              0x800080},
    {"red",                 0xFF0000},
    {"rosybrown",           0xBC8F8F},
    {"royalblue",           0x4169E1},
    {"saddlebrown",         0x8B4513},
    {"salmon",              0xFA8072},
    {"sandybrown",          0xF4A460},
    {"seagreen",            0x2E8B57},
    {"seashell",            0xFFF5EE},
    {"sienna",              0xA0522D},
    {"silver",              0xC0C0C0},
    {"skyblue",             0x87CEEB},
    {"slateblue",           0x6A5ACD},
    {"slategray",           0x708090},
    {"slategrey",           0x708090},
    {"snow",                0xFFFAFA},
    {"springgreen",         0x00FF7F},
    {"steelblue",           0x4682B4},
    {"tan",                 0xD2B48C},
    {"teal",                0x008080},
    {"thistle",             0xD8BFD8},
    {"tomato",              0xFF6347},
    {"turquoise",           0x40E0D0},
    {"violet",              0xEE82EE},
    {"wheat",               0xF5DEB3},
    {"white",               0xFFFFFF},
    {"whitesmoke",          0xF5F5F5},
    {"yellow",              0xFFFF00},
    {"yellowgreen",         0x9ACD32},
};

#define SUBRIP_MAX_STACKED_FONT_TAGS    16

/* Read the HTML-style attribute starting at *s, and skip *s past the value.
 * Set attr and val to the parsed attribute name and value.
 * Return 0 on success, or -1 if no valid attribute was found.
 */
static int read_attr(char **s, struct bstr *attr, struct bstr *val)
{
    char *eq = strchr(*s, '=');
    if (!eq)
        return -1;
    attr->start = *s;
    attr->len = eq - *s;
    for (int i = 0; i < attr->len; i++)
        if (!mp_isalnum(attr->start[i]))
            return -1;
    val->start = eq + 1;
    bool quoted = val->start[0] == '"';
    if (quoted)
        val->start++;
    unsigned char *end = strpbrk(val->start, quoted ? "\"" : " >");
    if (!end)
        return -1;
    val->len = end - val->start;
    *s = end + quoted;
    return 0;
}

static void convert_subrip(struct sd *sd, const char *orig,
                           char *dest, int dest_buffer_size)
{
    /* line is not const to avoid warnings with strtol, etc.
     * orig content won't be changed */
    char *line = (char *)orig;
    struct line new_line = {
        .buf = dest,
        .bufsize = dest_buffer_size,
    };
    struct font_tag font_stack[SUBRIP_MAX_STACKED_FONT_TAGS + 1];
    font_stack[0] = (struct font_tag){0}; // type with all defaults
    int sp = 0;

    while (*line && new_line.len < new_line.bufsize - 1) {
        char *orig_line = line;

        for (int i = 0; i < MP_ARRAY_SIZE(subrip_basic_tags); i++) {
            const struct tag_conv *tag = &subrip_basic_tags[i];
            int from_len = strlen(tag->from);
            if (strncmp(line, tag->from, from_len) == 0) {
                append_text(&new_line, "%s", tag->to);
                line += from_len;
            }
        }

        if (strncmp(line, "</font>", 7) == 0) {
            /* Closing font tag */
            line += 7;

            if (sp > 0) {
                struct font_tag *tag = &font_stack[sp];
                struct font_tag *last_tag = &tag[-1];
                sp--;

                if (tag->has_size) {
                    if (!last_tag->has_size)
                        append_text(&new_line, "{\\fs}");
                    else if (last_tag->size != tag->size)
                        append_text(&new_line, "{\\fs%d}", last_tag->size);
                }

                if (tag->has_color) {
                    if (!last_tag->has_color)
                        append_text(&new_line, "{\\c}");
                    else if (last_tag->color != tag->color)
                        append_text(&new_line, "{\\c&H%06X&}", last_tag->color);
                }

                if (tag->has_face) {
                    if (!last_tag->has_face)
                        append_text(&new_line, "{\\fn}");
                    else if (bstrcmp(last_tag->face, tag->face) != 0)
                        append_text(&new_line, "{\\fn%.*s}",
                                    BSTR_P(last_tag->face));
                }
            }
        } else if (strncmp(line, "<font ", 6) == 0
                   && sp + 1 < MP_ARRAY_SIZE(font_stack)) {
            /* Opening font tag */
            char *potential_font_tag_start = line;
            int len_backup = new_line.len;
            struct font_tag *tag = &font_stack[sp + 1];
            bool has_valid_attr = false;

            *tag = tag[-1]; // keep values from previous tag
            line += 6;

            while (*line && *line != '>') {
                if (*line == ' ') {
                    line++;
                    continue;
                }
                struct bstr attr, val;
                if (read_attr(&line, &attr, &val) < 0)
                    break;
                if (!bstrcmp0(attr, "size")) {
                    tag->size = bstrtoll(val, &val, 10);
                    if (val.len)
                        break;
                    append_text(&new_line, "{\\fs%d}", tag->size);
                    tag->has_size = true;
                    has_valid_attr = true;
                } else if (!bstrcmp0(attr, "color")) {
                    int found = 0;

                    // Try to lookup the string in standard web colors
                    for (int i = 0; i < MP_ARRAY_SIZE(subrip_web_colors); i++) {
                        char *color = subrip_web_colors[i].s;
                        if (bstrcasecmp(val, bstr0(color)) == 0) {
                            uint32_t xcolor = subrip_web_colors[i].v;
                            tag->color = ((xcolor & 0xff) << 16)
                                | (xcolor & 0xff00)
                                | ((xcolor & 0xff0000) >> 16);
                            found = 1;
                        }
                    }

                    // If it's not a web color it must be a HEX RGB value
                    if (!found) {
                        // Remove the leading '#'
                        bstr_eatstart(&val, bstr0("#"));
                        // Sometimes there are two '#'
                        bstr_eatstart(&val, bstr0("#"));

                        // Parse RRGGBB format
                        tag->color = bstrtoll(val, &val, 16) & 0x00ffffff;
                        if (!val.len) {
                            tag->color = ((tag->color & 0xff) << 16)
                                | (tag->color & 0xff00)
                                | ((tag->color & 0xff0000) >> 16);
                            found = 1;
                        }
                    }

                    if (found) {
                        append_text(&new_line, "{\\c&H%06X&}", tag->color);
                        tag->has_color = true;
                    } else {
                        // We didn't find any matching color
                        MP_WARN(sd, "unknown font color in subtitle: >%s<\n",
                                orig);
                        append_text(&new_line, "{\\c}");
                    }

                    has_valid_attr = true;
                } else if (!bstrcmp0(attr, "face")) {
                    /* Font face attribute */
                    tag->face = val;
                    append_text(&new_line, "{\\fn%.*s}", BSTR_P(tag->face));
                    tag->has_face = true;
                    has_valid_attr = true;
                } else
                    MP_WARN(sd, "unrecognized attribute \"%.*s\" in font tag\n",
                            BSTR_P(attr));
            }

            if (!has_valid_attr || *line != '>') { /* Not valid font tag */
                line = potential_font_tag_start;
                new_line.len = len_backup;
            } else {
                sp++;
                line++;
            }
        } else if (*line == '{') {
            char *end = strchr(line, '}');
            if (line[1] == '\\' && end) {
                // Likely ASS tag, pass them through
                // Note that ASS tags like {something\an8} are legal too (i.e.
                // the first character after '{' doesn't have to be '\'), but
                // consider these fringe cases not worth supporting.
                append_text_n(&new_line, line, end - line + 1);
                line = end + 1;
            } else {
                append_text(&new_line, "\\{");
                line++;
            }
        }

        /* Tag conversion code didn't match */
        if (line == orig_line)
            new_line.buf[new_line.len++] = *line++;
    }
    new_line.buf[new_line.len] = 0;
}

static const char *const srt_ass_extradata =
    "[Script Info]\n"
    "ScriptType: v4.00+\n"
    "PlayResX: 384\n"
    "PlayResY: 288\n";

static bool supports_format(const char *format)
{
    return format && (strcmp(format, "subrip") == 0 ||
                      strcmp(format, "text") == 0);
}

static int init(struct sd *sd)
{
    sd->output_codec = "ass-text";
    sd->output_extradata = (char *)srt_ass_extradata;
    sd->output_extradata_len = strlen(sd->output_extradata);
    return 0;
}

static void decode(struct sd *sd, struct demux_packet *packet)
{
    char dest[SD_MAX_LINE_LEN];
    // Assume input buffer is padded with 0
    convert_subrip(sd, packet->buffer, dest, sizeof(dest));
    sd_conv_add_packet(sd, dest, strlen(dest), packet->pts, packet->duration);
}

const struct sd_functions sd_srt = {
    .name = "srt",
    .supports_format = supports_format,
    .init = init,
    .decode = decode,
    .get_converted = sd_conv_def_get_converted,
    .reset = sd_conv_def_reset,
};