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vf_subtitles.c
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1 /*
2  * Copyright (c) 2011 Baptiste Coudurier
3  * Copyright (c) 2011 Stefano Sabatini
4  * Copyright (c) 2012 Clément Bœsch
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 /**
24  * @file
25  * Libass subtitles burning filter.
26  *
27  * @see{http://www.matroska.org/technical/specs/subtitles/ssa.html}
28  */
29 
30 #include <ass/ass.h>
31 
32 #include "config.h"
33 #if CONFIG_SUBTITLES_FILTER
34 # include "libavcodec/avcodec.h"
35 # include "libavformat/avformat.h"
36 #endif
37 #include "libavutil/avstring.h"
38 #include "libavutil/imgutils.h"
39 #include "libavutil/opt.h"
40 #include "libavutil/parseutils.h"
41 #include "drawutils.h"
42 #include "avfilter.h"
43 #include "internal.h"
44 #include "formats.h"
45 #include "video.h"
46 
47 typedef struct {
48  const AVClass *class;
49  ASS_Library *library;
50  ASS_Renderer *renderer;
51  ASS_Track *track;
52  char *filename;
53  char *charenc;
54  char *force_style;
56  uint8_t rgba_map[4];
57  int pix_step[4]; ///< steps per pixel for each plane of the main output
58  int original_w, original_h;
59  int shaping;
61 } AssContext;
62 
63 #define OFFSET(x) offsetof(AssContext, x)
64 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
65 
66 #define COMMON_OPTIONS \
67  {"filename", "set the filename of file to read", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS }, \
68  {"f", "set the filename of file to read", OFFSET(filename), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS }, \
69  {"original_size", "set the size of the original video (used to scale fonts)", OFFSET(original_w), AV_OPT_TYPE_IMAGE_SIZE, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS }, \
70 
71 /* libass supports a log level ranging from 0 to 7 */
72 static const int ass_libavfilter_log_level_map[] = {
73  [0] = AV_LOG_FATAL, /* MSGL_FATAL */
74  [1] = AV_LOG_ERROR, /* MSGL_ERR */
75  [2] = AV_LOG_WARNING, /* MSGL_WARN */
76  [3] = AV_LOG_WARNING, /* <undefined> */
77  [4] = AV_LOG_INFO, /* MSGL_INFO */
78  [5] = AV_LOG_INFO, /* <undefined> */
79  [6] = AV_LOG_VERBOSE, /* MSGL_V */
80  [7] = AV_LOG_DEBUG, /* MSGL_DBG2 */
81 };
82 
83 static void ass_log(int ass_level, const char *fmt, va_list args, void *ctx)
84 {
85  const int ass_level_clip = av_clip(ass_level, 0,
87  const int level = ass_libavfilter_log_level_map[ass_level_clip];
88 
89  av_vlog(ctx, level, fmt, args);
90  av_log(ctx, level, "\n");
91 }
92 
93 static av_cold int init(AVFilterContext *ctx)
94 {
95  AssContext *ass = ctx->priv;
96 
97  if (!ass->filename) {
98  av_log(ctx, AV_LOG_ERROR, "No filename provided!\n");
99  return AVERROR(EINVAL);
100  }
101 
102  ass->library = ass_library_init();
103  if (!ass->library) {
104  av_log(ctx, AV_LOG_ERROR, "Could not initialize libass.\n");
105  return AVERROR(EINVAL);
106  }
107  ass_set_message_cb(ass->library, ass_log, ctx);
108 
109  ass->renderer = ass_renderer_init(ass->library);
110  if (!ass->renderer) {
111  av_log(ctx, AV_LOG_ERROR, "Could not initialize libass renderer.\n");
112  return AVERROR(EINVAL);
113  }
114 
115  return 0;
116 }
117 
118 static av_cold void uninit(AVFilterContext *ctx)
119 {
120  AssContext *ass = ctx->priv;
121 
122  if (ass->track)
123  ass_free_track(ass->track);
124  if (ass->renderer)
125  ass_renderer_done(ass->renderer);
126  if (ass->library)
127  ass_library_done(ass->library);
128 }
129 
131 {
133 }
134 
135 static int config_input(AVFilterLink *inlink)
136 {
137  AssContext *ass = inlink->dst->priv;
138 
139  ff_draw_init(&ass->draw, inlink->format, 0);
140 
141  ass_set_frame_size (ass->renderer, inlink->w, inlink->h);
142  if (ass->original_w && ass->original_h)
143  ass_set_aspect_ratio(ass->renderer, (double)inlink->w / inlink->h,
144  (double)ass->original_w / ass->original_h);
145  if (ass->shaping != -1)
146  ass_set_shaper(ass->renderer, ass->shaping);
147 
148  return 0;
149 }
150 
151 /* libass stores an RGBA color in the format RRGGBBTT, where TT is the transparency level */
152 #define AR(c) ( (c)>>24)
153 #define AG(c) (((c)>>16)&0xFF)
154 #define AB(c) (((c)>>8) &0xFF)
155 #define AA(c) ((0xFF-(c)) &0xFF)
156 
157 static void overlay_ass_image(AssContext *ass, AVFrame *picref,
158  const ASS_Image *image)
159 {
160  for (; image; image = image->next) {
161  uint8_t rgba_color[] = {AR(image->color), AG(image->color), AB(image->color), AA(image->color)};
163  ff_draw_color(&ass->draw, &color, rgba_color);
164  ff_blend_mask(&ass->draw, &color,
165  picref->data, picref->linesize,
166  picref->width, picref->height,
167  image->bitmap, image->stride, image->w, image->h,
168  3, 0, image->dst_x, image->dst_y);
169  }
170 }
171 
172 static int filter_frame(AVFilterLink *inlink, AVFrame *picref)
173 {
174  AVFilterContext *ctx = inlink->dst;
175  AVFilterLink *outlink = ctx->outputs[0];
176  AssContext *ass = ctx->priv;
177  int detect_change = 0;
178  double time_ms = picref->pts * av_q2d(inlink->time_base) * 1000;
179  ASS_Image *image = ass_render_frame(ass->renderer, ass->track,
180  time_ms, &detect_change);
181 
182  if (detect_change)
183  av_log(ctx, AV_LOG_DEBUG, "Change happened at time ms:%f\n", time_ms);
184 
185  overlay_ass_image(ass, picref, image);
186 
187  return ff_filter_frame(outlink, picref);
188 }
189 
190 static const AVFilterPad ass_inputs[] = {
191  {
192  .name = "default",
193  .type = AVMEDIA_TYPE_VIDEO,
194  .filter_frame = filter_frame,
195  .config_props = config_input,
196  .needs_writable = 1,
197  },
198  { NULL }
199 };
200 
201 static const AVFilterPad ass_outputs[] = {
202  {
203  .name = "default",
204  .type = AVMEDIA_TYPE_VIDEO,
205  },
206  { NULL }
207 };
208 
209 #if CONFIG_ASS_FILTER
210 
211 static const AVOption ass_options[] = {
213  {"shaping", "set shaping engine", OFFSET(shaping), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 1, FLAGS, "shaping_mode"},
214  {"auto", NULL, 0, AV_OPT_TYPE_CONST, {.i64 = -1}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
215  {"simple", "simple shaping", 0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_SIMPLE}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
216  {"complex", "complex shaping", 0, AV_OPT_TYPE_CONST, {.i64 = ASS_SHAPING_COMPLEX}, INT_MIN, INT_MAX, FLAGS, "shaping_mode"},
217  {NULL},
218 };
219 
221 
222 static av_cold int init_ass(AVFilterContext *ctx)
223 {
224  AssContext *ass = ctx->priv;
225  int ret = init(ctx);
226 
227  if (ret < 0)
228  return ret;
229 
230  /* Initialize fonts */
231  ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
232 
233  ass->track = ass_read_file(ass->library, ass->filename, NULL);
234  if (!ass->track) {
235  av_log(ctx, AV_LOG_ERROR,
236  "Could not create a libass track when reading file '%s'\n",
237  ass->filename);
238  return AVERROR(EINVAL);
239  }
240  return 0;
241 }
242 
243 AVFilter ff_vf_ass = {
244  .name = "ass",
245  .description = NULL_IF_CONFIG_SMALL("Render ASS subtitles onto input video using the libass library."),
246  .priv_size = sizeof(AssContext),
247  .init = init_ass,
248  .uninit = uninit,
250  .inputs = ass_inputs,
251  .outputs = ass_outputs,
252  .priv_class = &ass_class,
253 };
254 #endif
255 
256 #if CONFIG_SUBTITLES_FILTER
257 
258 static const AVOption subtitles_options[] = {
260  {"charenc", "set input character encoding", OFFSET(charenc), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS},
261  {"stream_index", "set stream index", OFFSET(stream_index), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS},
262  {"si", "set stream index", OFFSET(stream_index), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, FLAGS},
263  {"force_style", "force subtitle style", OFFSET(force_style), AV_OPT_TYPE_STRING, {.str = NULL}, CHAR_MIN, CHAR_MAX, FLAGS},
264  {NULL},
265 };
266 
267 static const char * const font_mimetypes[] = {
268  "application/x-truetype-font",
269  "application/vnd.ms-opentype",
270  "application/x-font-ttf",
271  NULL
272 };
273 
274 static int attachment_is_font(AVStream * st)
275 {
276  const AVDictionaryEntry *tag = NULL;
277  int n;
278 
279  tag = av_dict_get(st->metadata, "mimetype", NULL, AV_DICT_MATCH_CASE);
280 
281  if (tag) {
282  for (n = 0; font_mimetypes[n]; n++) {
283  if (av_strcasecmp(font_mimetypes[n], tag->value) == 0)
284  return 1;
285  }
286  }
287  return 0;
288 }
289 
290 AVFILTER_DEFINE_CLASS(subtitles);
291 
292 static av_cold int init_subtitles(AVFilterContext *ctx)
293 {
294  int j, ret, sid;
295  int k = 0;
299  AVCodec *dec = NULL;
300  const AVCodecDescriptor *dec_desc;
301  AVStream *st;
302  AVPacket pkt;
303  AssContext *ass = ctx->priv;
304 
305  /* Init libass */
306  ret = init(ctx);
307  if (ret < 0)
308  return ret;
309  ass->track = ass_new_track(ass->library);
310  if (!ass->track) {
311  av_log(ctx, AV_LOG_ERROR, "Could not create a libass track\n");
312  return AVERROR(EINVAL);
313  }
314 
315  /* Open subtitles file */
316  ret = avformat_open_input(&fmt, ass->filename, NULL, NULL);
317  if (ret < 0) {
318  av_log(ctx, AV_LOG_ERROR, "Unable to open %s\n", ass->filename);
319  goto end;
320  }
321  ret = avformat_find_stream_info(fmt, NULL);
322  if (ret < 0)
323  goto end;
324 
325  /* Locate subtitles stream */
326  if (ass->stream_index < 0)
327  ret = av_find_best_stream(fmt, AVMEDIA_TYPE_SUBTITLE, -1, -1, NULL, 0);
328  else {
329  ret = -1;
330  if (ass->stream_index < fmt->nb_streams) {
331  for (j = 0; j < fmt->nb_streams; j++) {
332  if (fmt->streams[j]->codec->codec_type == AVMEDIA_TYPE_SUBTITLE) {
333  if (ass->stream_index == k) {
334  ret = j;
335  break;
336  }
337  k++;
338  }
339  }
340  }
341  }
342 
343  if (ret < 0) {
344  av_log(ctx, AV_LOG_ERROR, "Unable to locate subtitle stream in %s\n",
345  ass->filename);
346  goto end;
347  }
348  sid = ret;
349  st = fmt->streams[sid];
350 
351  /* Load attached fonts */
352  for (j = 0; j < fmt->nb_streams; j++) {
353  AVStream *st = fmt->streams[j];
355  attachment_is_font(st)) {
356  const AVDictionaryEntry *tag = NULL;
357  tag = av_dict_get(st->metadata, "filename", NULL,
359 
360  if (tag) {
361  av_log(ctx, AV_LOG_DEBUG, "Loading attached font: %s\n",
362  tag->value);
363  ass_add_font(ass->library, tag->value,
364  st->codec->extradata,
365  st->codec->extradata_size);
366  } else {
367  av_log(ctx, AV_LOG_WARNING,
368  "Font attachment has no filename, ignored.\n");
369  }
370  }
371  }
372 
373  /* Initialize fonts */
374  ass_set_fonts(ass->renderer, NULL, NULL, 1, NULL, 1);
375 
376  /* Open decoder */
377  dec_ctx = st->codec;
378  dec = avcodec_find_decoder(dec_ctx->codec_id);
379  if (!dec) {
380  av_log(ctx, AV_LOG_ERROR, "Failed to find subtitle codec %s\n",
381  avcodec_get_name(dec_ctx->codec_id));
382  return AVERROR(EINVAL);
383  }
384  dec_desc = avcodec_descriptor_get(dec_ctx->codec_id);
385  if (dec_desc && !(dec_desc->props & AV_CODEC_PROP_TEXT_SUB)) {
386  av_log(ctx, AV_LOG_ERROR,
387  "Only text based subtitles are currently supported\n");
388  return AVERROR_PATCHWELCOME;
389  }
390  if (ass->charenc)
391  av_dict_set(&codec_opts, "sub_charenc", ass->charenc, 0);
392  ret = avcodec_open2(dec_ctx, dec, &codec_opts);
393  if (ret < 0)
394  goto end;
395 
396  if (ass->force_style) {
397  char **list = NULL;
398  char *temp = NULL;
399  char *ptr = av_strtok(ass->force_style, ",", &temp);
400  int i = 0;
401  while (ptr) {
402  av_dynarray_add(&list, &i, ptr);
403  if (!list) {
404  ret = AVERROR(ENOMEM);
405  goto end;
406  }
407  ptr = av_strtok(NULL, ",", &temp);
408  }
409  av_dynarray_add(&list, &i, NULL);
410  if (!list) {
411  ret = AVERROR(ENOMEM);
412  goto end;
413  }
414  ass_set_style_overrides(ass->library, list);
415  av_free(list);
416  }
417  /* Decode subtitles and push them into the renderer (libass) */
418  if (dec_ctx->subtitle_header)
419  ass_process_codec_private(ass->track,
420  dec_ctx->subtitle_header,
421  dec_ctx->subtitle_header_size);
422  av_init_packet(&pkt);
423  pkt.data = NULL;
424  pkt.size = 0;
425  while (av_read_frame(fmt, &pkt) >= 0) {
426  int i, got_subtitle;
427  AVSubtitle sub = {0};
428 
429  if (pkt.stream_index == sid) {
430  ret = avcodec_decode_subtitle2(dec_ctx, &sub, &got_subtitle, &pkt);
431  if (ret < 0) {
432  av_log(ctx, AV_LOG_WARNING, "Error decoding: %s (ignored)\n",
433  av_err2str(ret));
434  } else if (got_subtitle) {
435  for (i = 0; i < sub.num_rects; i++) {
436  char *ass_line = sub.rects[i]->ass;
437  if (!ass_line)
438  break;
439  ass_process_data(ass->track, ass_line, strlen(ass_line));
440  }
441  }
442  }
443  av_free_packet(&pkt);
444  avsubtitle_free(&sub);
445  }
446 
447 end:
448  av_dict_free(&codec_opts);
449  if (dec_ctx)
450  avcodec_close(dec_ctx);
451  if (fmt)
452  avformat_close_input(&fmt);
453  return ret;
454 }
455 
456 AVFilter ff_vf_subtitles = {
457  .name = "subtitles",
458  .description = NULL_IF_CONFIG_SMALL("Render text subtitles onto input video using the libass library."),
459  .priv_size = sizeof(AssContext),
460  .init = init_subtitles,
461  .uninit = uninit,
463  .inputs = ass_inputs,
464  .outputs = ass_outputs,
465  .priv_class = &subtitles_class,
466 };
467 #endif