src/lib/ffmpeg_decoder.cc

   1 /*
   2     Copyright (C) 2012-2018 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic 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
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 /** @file  src/ffmpeg_decoder.cc
  22  *  @brief A decoder using FFmpeg to decode content.
  23  */
  24
  25 #include "filter.h"
  26 #include "exceptions.h"
  27 #include "image.h"
  28 #include "util.h"
  29 #include "log.h"
  30 #include "dcpomatic_log.h"
  31 #include "ffmpeg_decoder.h"
  32 #include "text_decoder.h"
  33 #include "ffmpeg_audio_stream.h"
  34 #include "ffmpeg_subtitle_stream.h"
  35 #include "video_filter_graph.h"
  36 #include "audio_buffers.h"
  37 #include "ffmpeg_content.h"
  38 #include "raw_image_proxy.h"
  39 #include "video_decoder.h"
  40 #include "film.h"
  41 #include "audio_decoder.h"
  42 #include "compose.hpp"
  43 #include "text_content.h"
  44 #include "audio_content.h"
  45 #include "frame_interval_checker.h"
  46 #include <dcp/subtitle_string.h>
  47 #include <sub/ssa_reader.h>
  48 #include <sub/subtitle.h>
  49 #include <sub/collect.h>
  50 extern "C" {
  51 #include <libavcodec/avcodec.h>
  52 #include <libavformat/avformat.h>
  53 }
  54 #include <boost/foreach.hpp>
  55 #include <boost/algorithm/string.hpp>
  56 #include <vector>
  57 #include <iomanip>
  58 #include <iostream>
  59 #include <stdint.h>
  60
  61 #include "i18n.h"
  62
  63 using std::cout;
  64 using std::string;
  65 using std::vector;
  66 using std::list;
  67 using std::min;
  68 using std::pair;
  69 using std::max;
  70 using std::map;
  71 using boost::shared_ptr;
  72 using boost::is_any_of;
  73 using boost::split;
  74 using boost::optional;
  75 using boost::dynamic_pointer_cast;
  76 using dcp::Size;
  77 using namespace dcpomatic;
  78
  79 FFmpegDecoder::FFmpegDecoder (shared_ptr<const Film> film, shared_ptr<const FFmpegContent> c, bool fast)
  80         : FFmpeg (c)
  81         , Decoder (film)
  82         , _have_current_subtitle (false)
  83 {
  84         if (c->video && c->video->use()) {
  85                 video.reset (new VideoDecoder (this, c));
  86                 _pts_offset = pts_offset (c->ffmpeg_audio_streams(), c->first_video(), c->active_video_frame_rate(film));
  87                 /* It doesn't matter what size or pixel format this is, it just needs to be black */
  88                 _black_image.reset (new Image (AV_PIX_FMT_RGB24, dcp::Size (128, 128), true));
  89                 _black_image->make_black ();
  90         } else {
  91                 _pts_offset = ContentTime ();
  92         }
  93
  94         if (c->audio) {
  95                 audio.reset (new AudioDecoder (this, c->audio, fast));
  96         }
  97
  98         if (c->only_text()) {
  99                 /* XXX: this time here should be the time of the first subtitle, not 0 */
 100                 text.push_back (shared_ptr<TextDecoder> (new TextDecoder (this, c->only_text(), ContentTime())));
 101         }
 102
 103         _next_time.resize (_format_context->nb_streams);
 104 }
 105
 106 void
 107 FFmpegDecoder::flush ()
 108 {
 109         /* Get any remaining frames */
 110
 111         _packet.data = 0;
 112         _packet.size = 0;
 113
 114         /* XXX: should we reset _packet.data and size after each *_decode_* call? */
 115
 116         while (video && decode_video_packet()) {}
 117
 118         if (audio) {
 119                 decode_audio_packet ();
 120         }
 121
 122         /* Make sure all streams are the same length and round up to the next video frame */
 123
 124         FrameRateChange const frc = film()->active_frame_rate_change(_ffmpeg_content->position());
 125         ContentTime full_length (_ffmpeg_content->full_length(film()), frc);
 126         full_length = full_length.ceil (frc.source);
 127         if (video) {
 128                 double const vfr = _ffmpeg_content->video_frame_rate().get();
 129                 Frame const f = full_length.frames_round (vfr);
 130                 Frame v = video->position(film()).get_value_or(ContentTime()).frames_round(vfr) + 1;
 131                 while (v < f) {
 132                         video->emit (film(), shared_ptr<const ImageProxy> (new RawImageProxy (_black_image)), v);
 133                         ++v;
 134                 }
 135         }
 136
 137         BOOST_FOREACH (shared_ptr<FFmpegAudioStream> i, _ffmpeg_content->ffmpeg_audio_streams ()) {
 138                 ContentTime a = audio->stream_position(film(), i);
 139                 /* Unfortunately if a is 0 that really means that we don't know the stream position since
 140                    there has been no data on it since the last seek.  In this case we'll just do nothing
 141                    here.  I'm not sure if that's the right idea.
 142                 */
 143                 if (a > ContentTime()) {
 144                         while (a < full_length) {
 145                                 ContentTime to_do = min (full_length - a, ContentTime::from_seconds (0.1));
 146                                 shared_ptr<AudioBuffers> silence (new AudioBuffers (i->channels(), to_do.frames_ceil (i->frame_rate())));
 147                                 silence->make_silent ();
 148                                 audio->emit (film(), i, silence, a);
 149                                 a += to_do;
 150                         }
 151                 }
 152         }
 153
 154         if (audio) {
 155                 audio->flush ();
 156         }
 157 }
 158
 159 bool
 160 FFmpegDecoder::pass ()
 161 {
 162 #ifdef DCPOMATIC_VARIANT_SWAROOP
 163         if (_ffmpeg_content->encrypted() && !_ffmpeg_content->kdm()) {
 164                 return true;
 165         }
 166 #endif
 167
 168         int r = av_read_frame (_format_context, &_packet);
 169
 170         /* AVERROR_INVALIDDATA can apparently be returned sometimes even when av_read_frame
 171            has pretty-much succeeded (and hence generated data which should be processed).
 172            Hence it makes sense to continue here in that case.
 173         */
 174         if (r < 0 && r != AVERROR_INVALIDDATA) {
 175                 if (r != AVERROR_EOF) {
 176                         /* Maybe we should fail here, but for now we'll just finish off instead */
 177                         char buf[256];
 178                         av_strerror (r, buf, sizeof(buf));
 179                         LOG_ERROR (N_("error on av_read_frame (%1) (%2)"), &buf[0], r);
 180                 }
 181
 182                 flush ();
 183                 return true;
 184         }
 185
 186         int const si = _packet.stream_index;
 187         shared_ptr<const FFmpegContent> fc = _ffmpeg_content;
 188
 189         if (_video_stream && si == _video_stream.get() && video && !video->ignore()) {
 190                 decode_video_packet ();
 191         } else if (fc->subtitle_stream() && fc->subtitle_stream()->uses_index(_format_context, si) && !only_text()->ignore()) {
 192                 decode_subtitle_packet ();
 193         } else {
 194                 decode_audio_packet ();
 195         }
 196
 197         av_packet_unref (&_packet);
 198         return false;
 199 }
 200
 201 /** @param data pointer to array of pointers to buffers.
 202  *  Only the first buffer will be used for non-planar data, otherwise there will be one per channel.
 203  */
 204 shared_ptr<AudioBuffers>
 205 FFmpegDecoder::deinterleave_audio (shared_ptr<FFmpegAudioStream> stream) const
 206 {
 207         DCPOMATIC_ASSERT (bytes_per_audio_sample (stream));
 208
 209 DCPOMATIC_DISABLE_WARNINGS
 210         int const size = av_samples_get_buffer_size (
 211                 0, stream->stream(_format_context)->codec->channels, _frame->nb_samples, audio_sample_format (stream), 1
 212                 );
 213 DCPOMATIC_ENABLE_WARNINGS
 214
 215         /* XXX: can't we just use _frame->nb_samples directly here? */
 216         /* XXX: can't we use swr_convert() to do the format conversion? */
 217
 218         /* Deinterleave and convert to float */
 219
 220         /* total_samples and frames will be rounded down here, so if there are stray samples at the end
 221            of the block that do not form a complete sample or frame they will be dropped.
 222         */
 223         int const total_samples = size / bytes_per_audio_sample (stream);
 224         int const channels = stream->channels();
 225         int const frames = total_samples / channels;
 226         shared_ptr<AudioBuffers> audio (new AudioBuffers (channels, frames));
 227         float** data = audio->data();
 228
 229         switch (audio_sample_format (stream)) {
 230         case AV_SAMPLE_FMT_U8:
 231         {
 232                 uint8_t* p = reinterpret_cast<uint8_t *> (_frame->data[0]);
 233                 int sample = 0;
 234                 int channel = 0;
 235                 for (int i = 0; i < total_samples; ++i) {
 236                         data[channel][sample] = float(*p++) / (1 << 23);
 237
 238                         ++channel;
 239                         if (channel == channels) {
 240                                 channel = 0;
 241                                 ++sample;
 242                         }
 243                 }
 244         }
 245         break;
 246
 247         case AV_SAMPLE_FMT_S16:
 248         {
 249                 int16_t* p = reinterpret_cast<int16_t *> (_frame->data[0]);
 250                 int sample = 0;
 251                 int channel = 0;
 252                 for (int i = 0; i < total_samples; ++i) {
 253                         data[channel][sample] = float(*p++) / (1 << 15);
 254
 255                         ++channel;
 256                         if (channel == channels) {
 257                                 channel = 0;
 258                                 ++sample;
 259                         }
 260                 }
 261         }
 262         break;
 263
 264         case AV_SAMPLE_FMT_S16P:
 265         {
 266                 int16_t** p = reinterpret_cast<int16_t **> (_frame->data);
 267                 for (int i = 0; i < channels; ++i) {
 268                         for (int j = 0; j < frames; ++j) {
 269                                 data[i][j] = static_cast<float>(p[i][j]) / (1 << 15);
 270                         }
 271                 }
 272         }
 273         break;
 274
 275         case AV_SAMPLE_FMT_S32:
 276         {
 277                 int32_t* p = reinterpret_cast<int32_t *> (_frame->data[0]);
 278                 int sample = 0;
 279                 int channel = 0;
 280                 for (int i = 0; i < total_samples; ++i) {
 281                         data[channel][sample] = static_cast<float>(*p++) / 2147483648;
 282
 283                         ++channel;
 284                         if (channel == channels) {
 285                                 channel = 0;
 286                                 ++sample;
 287                         }
 288                 }
 289         }
 290         break;
 291
 292         case AV_SAMPLE_FMT_S32P:
 293         {
 294                 int32_t** p = reinterpret_cast<int32_t **> (_frame->data);
 295                 for (int i = 0; i < channels; ++i) {
 296                         for (int j = 0; j < frames; ++j) {
 297                                 data[i][j] = static_cast<float>(p[i][j]) / 2147483648;
 298                         }
 299                 }
 300         }
 301         break;
 302
 303         case AV_SAMPLE_FMT_FLT:
 304         {
 305                 float* p = reinterpret_cast<float*> (_frame->data[0]);
 306                 int sample = 0;
 307                 int channel = 0;
 308                 for (int i = 0; i < total_samples; ++i) {
 309                         data[channel][sample] = *p++;
 310
 311                         ++channel;
 312                         if (channel == channels) {
 313                                 channel = 0;
 314                                 ++sample;
 315                         }
 316                 }
 317         }
 318         break;
 319
 320         case AV_SAMPLE_FMT_FLTP:
 321         {
 322                 float** p = reinterpret_cast<float**> (_frame->data);
 323                 DCPOMATIC_ASSERT (_frame->channels <= channels);
 324                 /* Sometimes there aren't as many channels in the _frame as in the stream */
 325                 for (int i = 0; i < _frame->channels; ++i) {
 326                         memcpy (data[i], p[i], frames * sizeof(float));
 327                 }
 328                 for (int i = _frame->channels; i < channels; ++i) {
 329                         audio->make_silent (i);
 330                 }
 331         }
 332         break;
 333
 334         default:
 335                 throw DecodeError (String::compose (_("Unrecognised audio sample format (%1)"), static_cast<int> (audio_sample_format (stream))));
 336         }
 337
 338         return audio;
 339 }
 340
 341 AVSampleFormat
 342 FFmpegDecoder::audio_sample_format (shared_ptr<FFmpegAudioStream> stream) const
 343 {
 344 DCPOMATIC_DISABLE_WARNINGS
 345         return stream->stream (_format_context)->codec->sample_fmt;
 346 DCPOMATIC_ENABLE_WARNINGS
 347 }
 348
 349 int
 350 FFmpegDecoder::bytes_per_audio_sample (shared_ptr<FFmpegAudioStream> stream) const
 351 {
 352         return av_get_bytes_per_sample (audio_sample_format (stream));
 353 }
 354
 355 void
 356 FFmpegDecoder::seek (ContentTime time, bool accurate)
 357 {
 358         Decoder::seek (time, accurate);
 359
 360         /* If we are doing an `accurate' seek, we need to use pre-roll, as
 361            we don't really know what the seek will give us.
 362         */
 363
 364         ContentTime pre_roll = accurate ? ContentTime::from_seconds (2) : ContentTime (0);
 365         time -= pre_roll;
 366
 367         /* XXX: it seems debatable whether PTS should be used here...
 368            http://www.mjbshaw.com/2012/04/seeking-in-ffmpeg-know-your-timestamp.html
 369         */
 370
 371         optional<int> stream;
 372
 373         if (_video_stream) {
 374                 stream = _video_stream;
 375         } else {
 376                 DCPOMATIC_ASSERT (_ffmpeg_content->audio);
 377                 shared_ptr<FFmpegAudioStream> s = dynamic_pointer_cast<FFmpegAudioStream> (_ffmpeg_content->audio->stream ());
 378                 if (s) {
 379                         stream = s->index (_format_context);
 380                 }
 381         }
 382
 383         DCPOMATIC_ASSERT (stream);
 384
 385         ContentTime u = time - _pts_offset;
 386         if (u < ContentTime ()) {
 387                 u = ContentTime ();
 388         }
 389         av_seek_frame (
 390                 _format_context,
 391                 stream.get(),
 392                 u.seconds() / av_q2d (_format_context->streams[stream.get()]->time_base),
 393                 AVSEEK_FLAG_BACKWARD
 394                 );
 395
 396         {
 397                 /* Force re-creation of filter graphs to reset them and hence to make sure
 398                    they don't have any pre-seek frames knocking about.
 399                 */
 400                 boost::mutex::scoped_lock lm (_filter_graphs_mutex);
 401                 _filter_graphs.clear ();
 402         }
 403
 404         if (video_codec_context ()) {
 405                 avcodec_flush_buffers (video_codec_context());
 406         }
 407
 408 DCPOMATIC_DISABLE_WARNINGS
 409         BOOST_FOREACH (shared_ptr<FFmpegAudioStream> i, ffmpeg_content()->ffmpeg_audio_streams()) {
 410                 avcodec_flush_buffers (i->stream(_format_context)->codec);
 411         }
 412 DCPOMATIC_ENABLE_WARNINGS
 413
 414         if (subtitle_codec_context ()) {
 415                 avcodec_flush_buffers (subtitle_codec_context ());
 416         }
 417
 418         _have_current_subtitle = false;
 419 }
 420
 421 void
 422 FFmpegDecoder::decode_audio_packet ()
 423 {
 424         /* Audio packets can contain multiple frames, so we may have to call avcodec_decode_audio4
 425            several times.
 426         */
 427
 428         AVPacket copy_packet = _packet;
 429         int const stream_index = copy_packet.stream_index;
 430
 431         /* XXX: inefficient */
 432         vector<shared_ptr<FFmpegAudioStream> > streams = ffmpeg_content()->ffmpeg_audio_streams ();
 433         vector<shared_ptr<FFmpegAudioStream> >::const_iterator stream = streams.begin ();
 434         while (stream != streams.end () && !(*stream)->uses_index (_format_context, stream_index)) {
 435                 ++stream;
 436         }
 437
 438         if (stream == streams.end ()) {
 439                 /* The packet's stream may not be an audio one; just ignore it in this method if so */
 440                 return;
 441         }
 442
 443 DCPOMATIC_DISABLE_WARNINGS
 444         while (copy_packet.size > 0) {
 445
 446                 int frame_finished;
 447                 int decode_result = avcodec_decode_audio4 ((*stream)->stream (_format_context)->codec, _frame, &frame_finished, &copy_packet);
 448                 if (decode_result < 0) {
 449                         /* avcodec_decode_audio4 can sometimes return an error even though it has decoded
 450                            some valid data; for example dca_subframe_footer can return AVERROR_INVALIDDATA
 451                            if it overreads the auxiliary data.  ffplay carries on if frame_finished is true,
 452                            even in the face of such an error, so I think we should too.
 453
 454                            Returning from the method here caused mantis #352.
 455                         */
 456                         LOG_WARNING ("avcodec_decode_audio4 failed (%1)", decode_result);
 457
 458                         /* Fudge decode_result so that we come out of the while loop when
 459                            we've processed this data.
 460                         */
 461                         decode_result = copy_packet.size;
 462                 }
 463
 464                 if (frame_finished) {
 465                         shared_ptr<AudioBuffers> data = deinterleave_audio (*stream);
 466
 467                         ContentTime ct;
 468                         if (_frame->pts == AV_NOPTS_VALUE && _next_time[stream_index]) {
 469                                 /* In some streams we see not every frame coming through with a timestamp; for those
 470                                    that have AV_NOPTS_VALUE we need to work out the timestamp ourselves.  This is
 471                                    particularly noticeable with TrueHD streams (see #1111).
 472                                 */
 473                                 ct = *_next_time[stream_index];
 474                         } else {
 475                                 ct = ContentTime::from_seconds (
 476                                         av_frame_get_best_effort_timestamp (_frame) *
 477                                         av_q2d ((*stream)->stream (_format_context)->time_base))
 478                                         + _pts_offset;
 479                         }
 480
 481                         _next_time[stream_index] = ct + ContentTime::from_frames(data->frames(), (*stream)->frame_rate());
 482
 483                         if (ct < ContentTime ()) {
 484                                 /* Discard audio data that comes before time 0 */
 485                                 Frame const remove = min (int64_t (data->frames()), (-ct).frames_ceil(double((*stream)->frame_rate ())));
 486                                 data->move (data->frames() - remove, remove, 0);
 487                                 data->set_frames (data->frames() - remove);
 488                                 ct += ContentTime::from_frames (remove, (*stream)->frame_rate ());
 489                         }
 490
 491                         if (ct < ContentTime()) {
 492                                 LOG_WARNING (
 493                                         "Crazy timestamp %1 for %2 samples in stream %3 packet pts %4 (ts=%5 tb=%6, off=%7)",
 494                                         to_string(ct),
 495                                         data->frames(),
 496                                         copy_packet.stream_index,
 497                                         copy_packet.pts,
 498                                         av_frame_get_best_effort_timestamp(_frame),
 499                                         av_q2d((*stream)->stream(_format_context)->time_base),
 500                                         to_string(_pts_offset)
 501                                         );
 502                         }
 503 DCPOMATIC_ENABLE_WARNINGS
 504
 505                         /* Give this data provided there is some, and its time is sane */
 506                         if (ct >= ContentTime() && data->frames() > 0) {
 507                                 audio->emit (film(), *stream, data, ct);
 508                         }
 509                 }
 510
 511                 copy_packet.data += decode_result;
 512                 copy_packet.size -= decode_result;
 513         }
 514 }
 515
 516 bool
 517 FFmpegDecoder::decode_video_packet ()
 518 {
 519         DCPOMATIC_ASSERT (_video_stream);
 520
 521         int frame_finished;
 522 DCPOMATIC_DISABLE_WARNINGS
 523         if (avcodec_decode_video2 (video_codec_context(), _frame, &frame_finished, &_packet) < 0 || !frame_finished) {
 524                 return false;
 525         }
 526 DCPOMATIC_ENABLE_WARNINGS
 527
 528         boost::mutex::scoped_lock lm (_filter_graphs_mutex);
 529
 530         shared_ptr<VideoFilterGraph> graph;
 531
 532         list<shared_ptr<VideoFilterGraph> >::iterator i = _filter_graphs.begin();
 533         while (i != _filter_graphs.end() && !(*i)->can_process (dcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format)) {
 534                 ++i;
 535         }
 536
 537         if (i == _filter_graphs.end ()) {
 538                 dcp::Fraction vfr (lrint(_ffmpeg_content->video_frame_rate().get() * 1000), 1000);
 539                 graph.reset (new VideoFilterGraph (dcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format, vfr));
 540                 graph->setup (_ffmpeg_content->filters ());
 541                 _filter_graphs.push_back (graph);
 542                 LOG_GENERAL (N_("New graph for %1x%2, pixel format %3"), _frame->width, _frame->height, _frame->format);
 543         } else {
 544                 graph = *i;
 545         }
 546
 547         list<pair<shared_ptr<Image>, int64_t> > images = graph->process (_frame);
 548
 549         for (list<pair<shared_ptr<Image>, int64_t> >::iterator i = images.begin(); i != images.end(); ++i) {
 550
 551                 shared_ptr<Image> image = i->first;
 552
 553                 if (i->second != AV_NOPTS_VALUE) {
 554                         double const pts = i->second * av_q2d (_format_context->streams[_video_stream.get()]->time_base) + _pts_offset.seconds ();
 555
 556                         video->emit (
 557                                 film(),
 558                                 shared_ptr<ImageProxy> (new RawImageProxy (image)),
 559                                 llrint(pts * _ffmpeg_content->active_video_frame_rate(film()))
 560                                 );
 561                 } else {
 562                         LOG_WARNING_NC ("Dropping frame without PTS");
 563                 }
 564         }
 565
 566         return true;
 567 }
 568
 569 void
 570 FFmpegDecoder::decode_subtitle_packet ()
 571 {
 572         int got_subtitle;
 573         AVSubtitle sub;
 574         if (avcodec_decode_subtitle2 (subtitle_codec_context(), &sub, &got_subtitle, &_packet) < 0 || !got_subtitle) {
 575                 return;
 576         }
 577
 578         /* Stop any current subtitle, either at the time it was supposed to stop, or now if now is sooner */
 579         if (_have_current_subtitle) {
 580                 if (_current_subtitle_to) {
 581                         only_text()->emit_stop (min(*_current_subtitle_to, subtitle_period(sub).from + _pts_offset));
 582                 } else {
 583                         only_text()->emit_stop (subtitle_period(sub).from + _pts_offset);
 584                 }
 585                 _have_current_subtitle = false;
 586         }
 587
 588         if (sub.num_rects <= 0) {
 589                 /* Nothing new in this subtitle */
 590                 return;
 591         }
 592
 593         /* Subtitle PTS (within the source, not taking into account any of the
 594            source that we may have chopped off for the DCP).
 595         */
 596         FFmpegSubtitlePeriod sub_period = subtitle_period (sub);
 597         ContentTime from;
 598         from = sub_period.from + _pts_offset;
 599         if (sub_period.to) {
 600                 _current_subtitle_to = *sub_period.to + _pts_offset;
 601         } else {
 602                 _current_subtitle_to = optional<ContentTime>();
 603                 _have_current_subtitle = true;
 604         }
 605
 606         for (unsigned int i = 0; i < sub.num_rects; ++i) {
 607                 AVSubtitleRect const * rect = sub.rects[i];
 608
 609                 switch (rect->type) {
 610                 case SUBTITLE_NONE:
 611                         break;
 612                 case SUBTITLE_BITMAP:
 613                         decode_bitmap_subtitle (rect, from);
 614                         break;
 615                 case SUBTITLE_TEXT:
 616                         cout << "XXX: SUBTITLE_TEXT " << rect->text << "\n";
 617                         break;
 618                 case SUBTITLE_ASS:
 619                         decode_ass_subtitle (rect->ass, from);
 620                         break;
 621                 }
 622         }
 623
 624         if (_current_subtitle_to) {
 625                 only_text()->emit_stop (*_current_subtitle_to);
 626         }
 627
 628         avsubtitle_free (&sub);
 629 }
 630
 631 void
 632 FFmpegDecoder::decode_bitmap_subtitle (AVSubtitleRect const * rect, ContentTime from)
 633 {
 634         /* Note BGRA is expressed little-endian, so the first byte in the word is B, second
 635            G, third R, fourth A.
 636         */
 637         shared_ptr<Image> image (new Image (AV_PIX_FMT_BGRA, dcp::Size (rect->w, rect->h), true));
 638
 639 #ifdef DCPOMATIC_HAVE_AVSUBTITLERECT_PICT
 640         /* Start of the first line in the subtitle */
 641         uint8_t* sub_p = rect->pict.data[0];
 642         /* sub_p looks up into a BGRA palette which is at rect->pict.data[1];
 643            (i.e. first byte B, second G, third R, fourth A)
 644         */
 645         uint8_t const * palette = rect->pict.data[1];
 646 #else
 647         /* Start of the first line in the subtitle */
 648         uint8_t* sub_p = rect->data[0];
 649         /* sub_p looks up into a BGRA palette which is at rect->data[1].
 650            (first byte B, second G, third R, fourth A)
 651         */
 652         uint8_t const * palette = rect->data[1];
 653 #endif
 654         /* And the stream has a map of those palette colours to colours
 655            chosen by the user; created a `mapped' palette from those settings.
 656         */
 657         map<RGBA, RGBA> colour_map = ffmpeg_content()->subtitle_stream()->colours ();
 658         vector<RGBA> mapped_palette (rect->nb_colors);
 659         for (int i = 0; i < rect->nb_colors; ++i) {
 660                 RGBA c (palette[2], palette[1], palette[0], palette[3]);
 661                 map<RGBA, RGBA>::const_iterator j = colour_map.find (c);
 662                 if (j != colour_map.end ()) {
 663                         mapped_palette[i] = j->second;
 664                 } else {
 665                         /* This colour was not found in the FFmpegSubtitleStream's colour map; probably because
 666                            it is from a project that was created before this stuff was added.  Just use the
 667                            colour straight from the original palette.
 668                         */
 669                         mapped_palette[i] = c;
 670                 }
 671                 palette += 4;
 672         }
 673
 674         /* Start of the output data */
 675         uint8_t* out_p = image->data()[0];
 676
 677         for (int y = 0; y < rect->h; ++y) {
 678                 uint8_t* sub_line_p = sub_p;
 679                 uint8_t* out_line_p = out_p;
 680                 for (int x = 0; x < rect->w; ++x) {
 681                         RGBA const p = mapped_palette[*sub_line_p++];
 682                         *out_line_p++ = p.b;
 683                         *out_line_p++ = p.g;
 684                         *out_line_p++ = p.r;
 685                         *out_line_p++ = p.a;
 686                 }
 687 #ifdef DCPOMATIC_HAVE_AVSUBTITLERECT_PICT
 688                 sub_p += rect->pict.linesize[0];
 689 #else
 690                 sub_p += rect->linesize[0];
 691 #endif
 692                 out_p += image->stride()[0];
 693         }
 694
 695         int target_width = subtitle_codec_context()->width;
 696         if (target_width == 0 && video_codec_context()) {
 697                 /* subtitle_codec_context()->width == 0 has been seen in the wild but I don't
 698                    know if it's supposed to mean something from FFmpeg's point of view.
 699                 */
 700                 target_width = video_codec_context()->width;
 701         }
 702         int target_height = subtitle_codec_context()->height;
 703         if (target_height == 0 && video_codec_context()) {
 704                 target_height = video_codec_context()->height;
 705         }
 706         DCPOMATIC_ASSERT (target_width);
 707         DCPOMATIC_ASSERT (target_height);
 708         dcpomatic::Rect<double> const scaled_rect (
 709                 static_cast<double> (rect->x) / target_width,
 710                 static_cast<double> (rect->y) / target_height,
 711                 static_cast<double> (rect->w) / target_width,
 712                 static_cast<double> (rect->h) / target_height
 713                 );
 714
 715         only_text()->emit_bitmap_start (from, image, scaled_rect);
 716 }
 717
 718 void
 719 FFmpegDecoder::decode_ass_subtitle (string ass, ContentTime from)
 720 {
 721         /* We have no styles and no Format: line, so I'm assuming that FFmpeg
 722            produces a single format of Dialogue: lines...
 723         */
 724
 725         int commas = 0;
 726         string text;
 727         for (size_t i = 0; i < ass.length(); ++i) {
 728                 if (commas < 9 && ass[i] == ',') {
 729                         ++commas;
 730                 } else if (commas == 9) {
 731                         text += ass[i];
 732                 }
 733         }
 734
 735         if (text.empty ()) {
 736                 return;
 737         }
 738
 739         sub::RawSubtitle base;
 740         list<sub::RawSubtitle> raw = sub::SSAReader::parse_line (
 741                 base,
 742                 text,
 743                 _ffmpeg_content->video->size().width,
 744                 _ffmpeg_content->video->size().height
 745                 );
 746
 747         BOOST_FOREACH (sub::Subtitle const & i, sub::collect<list<sub::Subtitle> > (raw)) {
 748                 only_text()->emit_plain_start (from, i);
 749         }
 750 }