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
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
|
/*
* Copyright (c) 2011 Baptiste Coudurier
* Copyright (c) 2011 Stefano Sabatini
* 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
*/
/**
* @file
* Libass subtitles burning filter.
*
* @see{http://www.matroska.org/technical/specs/subtitles/ssa.html}
*/
#include <ass/ass.h>
#include "config.h"
#if CONFIG_SUBTITLES_FILTER
# include "libavcodec/avcodec.h"
# include "libavformat/avformat.h"
#endif
#include "libavutil/avstring.h"
#include "libavutil/imgutils.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "drawutils.h"
#include "avfilter.h"
#include "internal.h"
#include "formats.h"
#include "video.h"
typedef struct AssContext {
const AVClass *class;
ASS_Library *library;
ASS_Renderer *renderer;
ASS_Track *track;
char *filename;
char *fontsdir;
char *charenc;
char *force_style;
int stream_index;
int alpha;
uint8_t rgba_map[4];
int pix_step[4]; ///< steps per pixel for each plane of the main output
int original_w, original_h;
int shaping;
FFDrawContext draw;
} AssContext;
#define OFFSET(x) offsetof(AssContext, x)
#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
#define COMMON_OPTIONS \
{"filename", "set the filename of file to read", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS }, \
{"f", "set the filename of file to read", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS }, \
{"original_size", "set the size of the original video (used to scale fonts)", OFFSET(original_w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, 0, 0, FLAGS }, \
{"fontsdir", "set the directory containing the fonts to read", OFFSET(fontsdir), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS }, \
{"alpha", "enable processing of alpha channel", OFFSET(alpha), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, FLAGS }, \
/* libass supports a log level ranging from 0 to 7 */
static const int ass_libavfilter_log_level_map[] = {
[0] = AV_LOG_FATAL, /* MSGL_FATAL */
[1] = AV_LOG_ERROR, /* MSGL_ERR */
[2] = AV_LOG_WARNING, /* MSGL_WARN */
[3] = AV_LOG_WARNING, /* <undefined> */
[4] = AV_LOG_INFO, /* MSGL_INFO */
[5] = AV_LOG_INFO, /* <undefined> */
[6] = AV_LOG_VERBOSE, /* MSGL_V */
[7] = AV_LOG_DEBUG, /* MSGL_DBG2 */
};
static void ass_log(int ass_level, const char *fmt, va_list args, void *ctx)
{
const int ass_level_clip = av_clip(ass_level, 0,
FF_ARRAY_ELEMS(ass_libavfilter_log_level_map) - 1);
const int level = ass_libavfilter_log_level_map[ass_level_clip];
av_vlog(ctx, level, fmt, args);
av_log(ctx, level, "\n");
}
static av_cold int init(AVFilterContext *ctx)
{
AssContext *ass = ctx->priv;
if (!ass->filename) {
av_log(ctx, AV_LOG_ERROR, "No filename provided!\n");
return AVERROR(EINVAL);
}
ass->library = ass_library_init();
if (!ass->library) {
av_log(ctx, AV_LOG_ERROR, "Could not initialize libass.\n");
return AVERROR(EINVAL);
}
ass_set_message_cb(ass->library, ass_log, ctx);
ass_set_fonts_dir(ass->library, ass->fontsdir);
ass_set_extract_fonts(ass->library, 1);
ass->renderer = ass_renderer_init(ass->library);
if (!ass->renderer) {
av_log(ctx, AV_LOG_ERROR, "Could not initialize libass renderer.\n");
return AVERROR(EINVAL);
}
return 0;
}
static av_cold void uninit(AVFilterContext *ctx)
{
AssContext *ass = ctx->priv;
if (ass->track)
ass_free_track(ass->track);
if (ass->renderer)
ass_renderer_done(ass->renderer);
if (ass->library)
ass_library_done(ass->library);
}
static int query_formats(AVFilterContext *ctx)
{
return ff_set_common_formats(ctx, ff_draw_supported_pixel_formats(0));
}
static int config_input(AVFilterLink *inlink)
{
AssContext *ass = inlink->dst->priv;
ff_draw_init(&ass->draw, inlink->format, ass->alpha ? FF_DRAW_PROCESS_ALPHA : 0);
ass_set_frame_size (ass->renderer, inlink->w, inlink->h);
if (ass->original_w && ass->original_h)
ass_set_aspect_ratio(ass->renderer, (double)inlink->w / inlink->h,
(double)ass->original_w / ass->original_h);
if (ass->shaping != -1)
ass_set_shaper(ass->renderer, ass->shaping);
return 0;
}
/* libass stores an RGBA color in the format RRGGBBTT, where TT is the transparency level */
#define AR(c) ( (c)>>24)
#define AG(c) (((c)>>16)&0xFF)
#define AB(c) (((c)>>8) &0xFF)
#define AA(c) ((0xFF-(c)) &0xFF)
static void overlay_ass_image(AssContext *ass, AVFrame *picref,
const ASS_Image *image)
{
for (; image; image = image->next) {
uint8_t rgba_color[] = {AR(image->color), AG(image->color), AB(image->color), AA(image->color)};
FFDrawColor color;
ff_draw_color(&ass->draw, &color, rgba_color);
ff_blend_mask(&ass->draw, &color,
picref->data, picref->linesize,
picref->width, picref->height,
image->bitmap, image->stride, image->w, image->h,
3, 0, image->dst_x, image->dst_y);
}
}
static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
{
AVFilterContext *ctx = inlink->dst;
AVFilterLink *outlink = ctx->outputs[0];
AssContext *ass = ctx->priv;
int detect_change = 0;
double time_ms = picref->pts * av_q2d(inlink->time_base) * 1000;
ASS_Image *image = ass_render_frame(ass->renderer, ass->track,
time_ms, &detect_change);
if (detect_change)
av_log(ctx, AV_LOG_DEBUG, "Change happened at time ms:%f\n", time_ms);
overlay_ass_image(ass, picref, image);
return ff_filter_frame(outlink, picref);
}
static const AVFilterPad ass_inputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
.flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
.filter_frame = filter_frame,
.config_props = config_input,
},
{ NULL }
};
static const AVFilterPad ass_outputs[] = {
{
.name = "default",
.type = AVMEDIA_TYPE_VIDEO,
},
{ NULL }
};
#if CONFIG_ASS_FILTER
static const AVOption ass_options[] = {
COMMON_OPTIONS
{"shaping", "set shaping engine", OFFSET(shaping), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, FLAGS, "shaping_mode"},
{"auto", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = -1}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
{"simple", "simple shaping", 0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_SIMPLE}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
{"complex", "complex shaping", 0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_COMPLEX}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
{NULL},
};
AVFILTER_DEFINE_CLASS(ass);
static av_cold int init_ass(AVFilterContext *ctx)
{
AssContext *ass = ctx->priv;
int ret = init(ctx);
if (ret < 0)
return ret;
/* Initialize fonts */
ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
ass->track = ass_read_file(ass->library, ass->filename, NULL);
if (!ass->track) {
av_log(ctx, AV_LOG_ERROR,
"Could not create a libass track when reading file '%s'\n",
ass->filename);
return AVERROR(EINVAL);
}
return 0;
}
const AVFilter ff_vf_ass = {
.name = "ass",
.description = NULL_IF_CONFIG_SMALL("Render ASS subtitles onto input video using the libass library."),
.priv_size = sizeof(AssContext),
.init = init_ass,
.uninit = uninit,
.query_formats = query_formats,
.inputs = ass_inputs,
.outputs = ass_outputs,
.priv_class = &ass_class,
};
#endif
#if CONFIG_SUBTITLES_FILTER
static const AVOption subtitles_options[] = {
COMMON_OPTIONS
{"charenc", "set input character encoding", OFFSET(charenc), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS},
{"stream_index", "set stream index", OFFSET(stream_index), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS},
{"si", "set stream index", OFFSET(stream_index), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS},
{"force_style", "force subtitle style", OFFSET(force_style), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, FLAGS},
{NULL},
};
static const char * const font_mimetypes[] = {
"application/x-truetype-font",
"application/vnd.ms-opentype",
"application/x-font-ttf",
NULL
};
static int attachment_is_font(AVStream * st)
{
const AVDictionaryEntry *tag = NULL;
int n;
tag = av_dict_get(st->metadata, "mimetype", NULL, AV_DICT_MATCH_CASE);
if (tag) {
for (n = 0; font_mimetypes[n]; n++) {
if (av_strcasecmp(font_mimetypes[n], tag->value) == 0)
return 1;
}
}
return 0;
}
AVFILTER_DEFINE_CLASS(subtitles);
static av_cold int init_subtitles(AVFilterContext *ctx)
{
int j, ret, sid;
int k = 0;
AVDictionary *codec_opts = NULL;
AVFormatContext *fmt = NULL;
AVCodecContext *dec_ctx = NULL;
const AVCodec *dec;
const AVCodecDescriptor *dec_desc;
AVStream *st;
AVPacket pkt;
AssContext *ass = ctx->priv;
/* Init libass */
ret = init(ctx);
if (ret < 0)
return ret;
ass->track = ass_new_track(ass->library);
if (!ass->track) {
av_log(ctx, AV_LOG_ERROR, "Could not create a libass track\n");
return AVERROR(EINVAL);
}
/* Open subtitles file */
ret = avformat_open_input(&fmt, ass->filename, NULL, NULL);
if (ret < 0) {
av_log(ctx, AV_LOG_ERROR, "Unable to open %s\n", ass->filename);
goto end;
}
ret = avformat_find_stream_info(fmt, NULL);
if (ret < 0)
goto end;
/* Locate subtitles stream */
if (ass->stream_index < 0)
ret = av_find_best_stream(fmt, AVMEDIA_TYPE_SUBTITLE, -1, -1, NULL, 0);
else {
ret = -1;
if (ass->stream_index < fmt->nb_streams) {
for (j = 0; j < fmt->nb_streams; j++) {
if (fmt->streams[j]->codecpar->codec_type == AVMEDIA_TYPE_SUBTITLE) {
if (ass->stream_index == k) {
ret = j;
break;
}
k++;
}
}
}
}
if (ret < 0) {
av_log(ctx, AV_LOG_ERROR, "Unable to locate subtitle stream in %s\n",
ass->filename);
goto end;
}
sid = ret;
st = fmt->streams[sid];
/* Load attached fonts */
for (j = 0; j < fmt->nb_streams; j++) {
AVStream *st = fmt->streams[j];
if (st->codecpar->codec_type == AVMEDIA_TYPE_ATTACHMENT &&
attachment_is_font(st)) {
const AVDictionaryEntry *tag = NULL;
tag = av_dict_get(st->metadata, "filename", NULL,
AV_DICT_MATCH_CASE);
if (tag) {
av_log(ctx, AV_LOG_DEBUG, "Loading attached font: %s\n",
tag->value);
ass_add_font(ass->library, tag->value,
st->codecpar->extradata,
st->codecpar->extradata_size);
} else {
av_log(ctx, AV_LOG_WARNING,
"Font attachment has no filename, ignored.\n");
}
}
}
/* Initialize fonts */
ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
/* Open decoder */
dec = avcodec_find_decoder(st->codecpar->codec_id);
if (!dec) {
av_log(ctx, AV_LOG_ERROR, "Failed to find subtitle codec %s\n",
avcodec_get_name(st->codecpar->codec_id));
ret = AVERROR_DECODER_NOT_FOUND;
goto end;
}
dec_desc = avcodec_descriptor_get(st->codecpar->codec_id);
if (dec_desc && !(dec_desc->props & AV_CODEC_PROP_TEXT_SUB)) {
av_log(ctx, AV_LOG_ERROR,
"Only text based subtitles are currently supported\n");
ret = AVERROR_PATCHWELCOME;
goto end;
}
if (ass->charenc)
av_dict_set(&codec_opts, "sub_charenc", ass->charenc, 0);
av_dict_set(&codec_opts, "sub_text_format", "ass", 0);
dec_ctx = avcodec_alloc_context3(dec);
if (!dec_ctx) {
ret = AVERROR(ENOMEM);
goto end;
}
ret = avcodec_parameters_to_context(dec_ctx, st->codecpar);
if (ret < 0)
goto end;
/*
* This is required by the decoding process in order to rescale the
* timestamps: in the current API the decoded subtitles have their pts
* expressed in AV_TIME_BASE, and thus the lavc internals need to know the
* stream time base in order to achieve the rescaling.
*
* That API is old and needs to be reworked to match behaviour with A/V.
*/
dec_ctx->pkt_timebase = st->time_base;
ret = avcodec_open2(dec_ctx, NULL, &codec_opts);
if (ret < 0)
goto end;
if (ass->force_style) {
char **list = NULL;
char *temp = NULL;
char *ptr = av_strtok(ass->force_style, ",", &temp);
int i = 0;
while (ptr) {
av_dynarray_add(&list, &i, ptr);
if (!list) {
ret = AVERROR(ENOMEM);
goto end;
}
ptr = av_strtok(NULL, ",", &temp);
}
av_dynarray_add(&list, &i, NULL);
if (!list) {
ret = AVERROR(ENOMEM);
goto end;
}
ass_set_style_overrides(ass->library, list);
av_free(list);
}
/* Decode subtitles and push them into the renderer (libass) */
if (dec_ctx->subtitle_header)
ass_process_codec_private(ass->track,
dec_ctx->subtitle_header,
dec_ctx->subtitle_header_size);
while (av_read_frame(fmt, &pkt) >= 0) {
int i, got_subtitle;
AVSubtitle sub = {0};
if (pkt.stream_index == sid) {
ret = avcodec_decode_subtitle2(dec_ctx, &sub, &got_subtitle, &pkt);
if (ret < 0) {
av_log(ctx, AV_LOG_WARNING, "Error decoding: %s (ignored)\n",
av_err2str(ret));
} else if (got_subtitle) {
const int64_t start_time = av_rescale_q(sub.pts, AV_TIME_BASE_Q, av_make_q(1, 1000));
const int64_t duration = sub.end_display_time;
for (i = 0; i < sub.num_rects; i++) {
char *ass_line = sub.rects[i]->ass;
if (!ass_line)
break;
ass_process_chunk(ass->track, ass_line, strlen(ass_line),
start_time, duration);
}
}
}
av_packet_unref(&pkt);
avsubtitle_free(&sub);
}
end:
av_dict_free(&codec_opts);
avcodec_free_context(&dec_ctx);
avformat_close_input(&fmt);
return ret;
}
const AVFilter ff_vf_subtitles = {
.name = "subtitles",
.description = NULL_IF_CONFIG_SMALL("Render text subtitles onto input video using the libass library."),
.priv_size = sizeof(AssContext),
.init = init_subtitles,
.uninit = uninit,
.query_formats = query_formats,
.inputs = ass_inputs,
.outputs = ass_outputs,
.priv_class = &subtitles_class,
};
#endif
|