src/wx/film_viewer.cc

   1 /*
   2     Copyright (C) 2012-2019 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/film_viewer.cc
  22  *  @brief A wx widget to view a preview of a Film.
  23  */
  24
  25 #include "film_viewer.h"
  26 #include "playhead_to_timecode_dialog.h"
  27 #include "playhead_to_frame_dialog.h"
  28 #include "wx_util.h"
  29 #include "closed_captions_dialog.h"
  30 #include "lib/film.h"
  31 #include "lib/ratio.h"
  32 #include "lib/util.h"
  33 #include "lib/job_manager.h"
  34 #include "lib/image.h"
  35 #include "lib/exceptions.h"
  36 #include "lib/examine_content_job.h"
  37 #include "lib/filter.h"
  38 #include "lib/player.h"
  39 #include "lib/player_video.h"
  40 #include "lib/video_content.h"
  41 #include "lib/video_decoder.h"
  42 #include "lib/timer.h"
  43 #include "lib/butler.h"
  44 #include "lib/log.h"
  45 #include "lib/config.h"
  46 #include "lib/compose.hpp"
  47 #include "lib/dcpomatic_log.h"
  48 extern "C" {
  49 #include <libavutil/pixfmt.h>
  50 }
  51 #include <dcp/exceptions.h>
  52 #include <wx/tglbtn.h>
  53 #include <iostream>
  54 #include <iomanip>
  55
  56 using std::string;
  57 using std::pair;
  58 using std::min;
  59 using std::max;
  60 using std::cout;
  61 using std::list;
  62 using std::bad_alloc;
  63 using std::make_pair;
  64 using std::exception;
  65 using boost::shared_ptr;
  66 using boost::dynamic_pointer_cast;
  67 using boost::weak_ptr;
  68 using boost::optional;
  69 using dcp::Size;
  70 using namespace dcpomatic;
  71
  72 static
  73 int
  74 rtaudio_callback (void* out, void *, unsigned int frames, double, RtAudioStreamStatus, void* data)
  75 {
  76         return reinterpret_cast<FilmViewer*>(data)->audio_callback (out, frames);
  77 }
  78
  79 FilmViewer::FilmViewer (wxWindow* p)
  80         : _panel (new wxPanel (p))
  81         , _coalesce_player_changes (false)
  82         , _audio (DCPOMATIC_RTAUDIO_API)
  83         , _audio_channels (0)
  84         , _audio_block_size (1024)
  85         , _playing (false)
  86         , _latency_history_count (0)
  87         , _dropped (0)
  88         , _closed_captions_dialog (new ClosedCaptionsDialog(p, this))
  89         , _outline_content (false)
  90         , _eyes (EYES_LEFT)
  91         , _pad_black (false)
  92 #ifdef DCPOMATIC_VARIANT_SWAROOP
  93         , _in_watermark (false)
  94         , _background_image (false)
  95 #endif
  96         , _state_timer ("viewer")
  97         , _gets (0)
  98 {
  99 #ifndef __WXOSX__
 100         _panel->SetDoubleBuffered (true);
 101 #endif
 102
 103         _panel->SetBackgroundStyle (wxBG_STYLE_PAINT);
 104         _panel->SetBackgroundColour (*wxBLACK);
 105
 106         _panel->Bind (wxEVT_PAINT, boost::bind (&FilmViewer::paint_panel, this));
 107         _panel->Bind (wxEVT_SIZE,  boost::bind (&FilmViewer::panel_sized, this, _1));
 108         _timer.Bind  (wxEVT_TIMER, boost::bind (&FilmViewer::timer, this));
 109
 110         set_film (shared_ptr<Film> ());
 111
 112         _config_changed_connection = Config::instance()->Changed.connect (bind (&FilmViewer::config_changed, this, _1));
 113         config_changed (Config::SOUND_OUTPUT);
 114 }
 115
 116 FilmViewer::~FilmViewer ()
 117 {
 118         stop ();
 119 }
 120
 121 void
 122 FilmViewer::set_film (shared_ptr<Film> film)
 123 {
 124         if (_film == film) {
 125                 return;
 126         }
 127
 128         _film = film;
 129         _video_position = DCPTime ();
 130         _player_video.first.reset ();
 131         _player_video.second = DCPTime ();
 132
 133         _frame.reset ();
 134         _closed_captions_dialog->clear ();
 135
 136         if (!_film) {
 137                 _player.reset ();
 138                 recreate_butler ();
 139                 _frame.reset ();
 140                 refresh_panel ();
 141                 return;
 142         }
 143
 144         try {
 145                 _player.reset (new Player (_film, _film->playlist ()));
 146                 _player->set_fast ();
 147                 if (_dcp_decode_reduction) {
 148                         _player->set_dcp_decode_reduction (_dcp_decode_reduction);
 149                 }
 150         } catch (bad_alloc &) {
 151                 error_dialog (_panel, _("There is not enough free memory to do that."));
 152                 _film.reset ();
 153                 return;
 154         }
 155
 156         _player->set_always_burn_open_subtitles ();
 157         _player->set_play_referenced ();
 158
 159         _film->Change.connect (boost::bind (&FilmViewer::film_change, this, _1, _2));
 160         _player->Change.connect (boost::bind (&FilmViewer::player_change, this, _1, _2, _3));
 161
 162         /* Keep about 1 second's worth of history samples */
 163         _latency_history_count = _film->audio_frame_rate() / _audio_block_size;
 164
 165         recreate_butler ();
 166
 167         calculate_sizes ();
 168         slow_refresh ();
 169 }
 170
 171 void
 172 FilmViewer::recreate_butler ()
 173 {
 174         bool const was_running = stop ();
 175         _butler.reset ();
 176
 177         if (!_film) {
 178                 return;
 179         }
 180
 181         AudioMapping map = AudioMapping (_film->audio_channels(), _audio_channels);
 182
 183         if (_audio_channels != 2 || _film->audio_channels() < 3) {
 184                 for (int i = 0; i < min (_film->audio_channels(), _audio_channels); ++i) {
 185                         map.set (i, i, 1);
 186                 }
 187         } else {
 188                 /* Special case: stereo output, at least 3 channel input.
 189                    Map so that Lt = L(-3dB) + Ls(-3dB) + C(-6dB) + Lfe(-10dB)
 190                                Rt = R(-3dB) + Rs(-3dB) + C(-6dB) + Lfe(-10dB)
 191                 */
 192                 map.set (dcp::LEFT,   0, 1 / sqrt(2)); // L -> Lt
 193                 map.set (dcp::RIGHT,  1, 1 / sqrt(2)); // R -> Rt
 194                 map.set (dcp::CENTRE, 0, 1 / 2.0); // C -> Lt
 195                 map.set (dcp::CENTRE, 1, 1 / 2.0); // C -> Rt
 196                 map.set (dcp::LFE,    0, 1 / sqrt(10)); // Lfe -> Lt
 197                 map.set (dcp::LFE,    1, 1 / sqrt(10)); // Lfe -> Rt
 198                 map.set (dcp::LS,     0, 1 / sqrt(2)); // Ls -> Lt
 199                 map.set (dcp::RS,     1, 1 / sqrt(2)); // Rs -> Rt
 200         }
 201
 202         _butler.reset (new Butler(_player, map, _audio_channels, bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true));
 203         if (!Config::instance()->sound() && !_audio.isStreamOpen()) {
 204                 _butler->disable_audio ();
 205         }
 206
 207         _closed_captions_dialog->set_film_and_butler (_film, _butler);
 208
 209         if (was_running) {
 210                 start ();
 211         }
 212 }
 213
 214 void
 215 FilmViewer::refresh_panel ()
 216 {
 217         _state_timer.set ("refresh-panel");
 218         _panel->Refresh ();
 219         _panel->Update ();
 220         _state_timer.unset ();
 221 }
 222
 223 void
 224 FilmViewer::get ()
 225 {
 226         DCPOMATIC_ASSERT (_butler);
 227         ++_gets;
 228
 229         do {
 230                 Butler::Error e;
 231                 _player_video = _butler->get_video (&e);
 232                 if (!_player_video.first && e == Butler::AGAIN) {
 233                         signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
 234                         return;
 235                 }
 236         } while (
 237                 _player_video.first &&
 238                 _film->three_d() &&
 239                 _eyes != _player_video.first->eyes() &&
 240                 _player_video.first->eyes() != EYES_BOTH
 241                 );
 242
 243         _butler->rethrow ();
 244
 245         display_player_video ();
 246 }
 247
 248 void
 249 FilmViewer::display_player_video ()
 250 {
 251         if (!_player_video.first) {
 252                 _frame.reset ();
 253                 refresh_panel ();
 254                 return;
 255         }
 256
 257         if (_playing && (time() - _player_video.second) > one_video_frame()) {
 258                 /* Too late; just drop this frame before we try to get its image (which will be the time-consuming
 259                    part if this frame is J2K).
 260                 */
 261                 _video_position = _player_video.second;
 262                 ++_dropped;
 263                 return;
 264         }
 265
 266         /* In an ideal world, what we would do here is:
 267          *
 268          * 1. convert to XYZ exactly as we do in the DCP creation path.
 269          * 2. convert back to RGB for the preview display, compensating
 270          *    for the monitor etc. etc.
 271          *
 272          * but this is inefficient if the source is RGB.  Since we don't
 273          * (currently) care too much about the precise accuracy of the preview's
 274          * colour mapping (and we care more about its speed) we try to short-
 275          * circuit this "ideal" situation in some cases.
 276          *
 277          * The content's specified colour conversion indicates the colourspace
 278          * which the content is in (according to the user).
 279          *
 280          * PlayerVideo::image (bound to PlayerVideo::force) will take the source
 281          * image and convert it (from whatever the user has said it is) to RGB.
 282          */
 283
 284         _state_timer.set ("get image");
 285         _frame = _player_video.first->image (bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true);
 286
 287         _state_timer.set ("ImageChanged");
 288         ImageChanged (_player_video.first);
 289         _state_timer.unset ();
 290
 291         _video_position = _player_video.second;
 292         _inter_position = _player_video.first->inter_position ();
 293         _inter_size = _player_video.first->inter_size ();
 294
 295         refresh_panel ();
 296
 297         _closed_captions_dialog->update (time());
 298 }
 299
 300 void
 301 FilmViewer::timer ()
 302 {
 303         if (!_film || !_playing) {
 304                 return;
 305         }
 306
 307         get ();
 308         PositionChanged ();
 309         DCPTime const next = _video_position + one_video_frame();
 310
 311         if (next >= _film->length()) {
 312                 stop ();
 313                 Finished ();
 314                 return;
 315         }
 316
 317         LOG_DEBUG_PLAYER("%1 -> %2; delay %3", next.seconds(), time().seconds(), max((next.seconds() - time().seconds()) * 1000, 1.0));
 318         _timer.Start (max ((next.seconds() - time().seconds()) * 1000, 1.0), wxTIMER_ONE_SHOT);
 319
 320         if (_butler) {
 321                 _butler->rethrow ();
 322         }
 323 }
 324
 325 bool
 326 #ifdef DCPOMATIC_VARIANT_SWAROOP
 327 FilmViewer::maybe_draw_background_image (wxPaintDC& dc)
 328 {
 329         optional<boost::filesystem::path> bg = Config::instance()->player_background_image();
 330         if (bg) {
 331                 wxImage image (std_to_wx(bg->string()));
 332                 wxBitmap bitmap (image);
 333                 dc.DrawBitmap (bitmap, max(0, (_panel_size.width - image.GetSize().GetWidth()) / 2), max(0, (_panel_size.height - image.GetSize().GetHeight()) / 2));
 334                 return true;
 335         }
 336
 337         return false;
 338 }
 339 #else
 340 FilmViewer::maybe_draw_background_image (wxPaintDC &)
 341 {
 342         return false;
 343 }
 344 #endif
 345
 346 void
 347 FilmViewer::paint_panel ()
 348 {
 349         _state_timer.set ("paint-panel");
 350
 351         wxPaintDC dc (_panel);
 352
 353 #ifdef DCPOMATIC_VARIANT_SWAROOP
 354         if (_background_image) {
 355                 dc.Clear ();
 356                 maybe_draw_background_image (dc);
 357                 _state_timer.unset ();
 358                 return;
 359         }
 360 #endif
 361
 362         if (!_out_size.width || !_out_size.height || !_film || !_frame || _out_size != _frame->size()) {
 363                 dc.Clear ();
 364         } else {
 365
 366                 wxImage frame (_out_size.width, _out_size.height, _frame->data()[0], true);
 367                 wxBitmap frame_bitmap (frame);
 368                 dc.DrawBitmap (frame_bitmap, 0, max(0, (_panel_size.height - _out_size.height) / 2));
 369
 370 #ifdef DCPOMATIC_VARIANT_SWAROOP
 371                 DCPTime const period = DCPTime::from_seconds(Config::instance()->player_watermark_period() * 60);
 372                 int64_t n = _video_position.get() / period.get();
 373                 DCPTime from(n * period.get());
 374                 DCPTime to = from + DCPTime::from_seconds(Config::instance()->player_watermark_duration() / 1000.0);
 375                 if (from <= _video_position && _video_position <= to) {
 376                         if (!_in_watermark) {
 377                                 _in_watermark = true;
 378                                 _watermark_x = rand() % _panel_size.width;
 379                                 _watermark_y = rand() % _panel_size.height;
 380                         }
 381                         dc.SetTextForeground(*wxWHITE);
 382                         string wm = Config::instance()->player_watermark_theatre();
 383                         boost::posix_time::ptime t = boost::posix_time::second_clock::local_time();
 384                         wm += "\n" + boost::posix_time::to_iso_extended_string(t);
 385                         dc.DrawText(std_to_wx(wm), _watermark_x, _watermark_y);
 386                 } else {
 387                         _in_watermark = false;
 388                 }
 389 #endif
 390         }
 391
 392         if (_out_size.width < _panel_size.width) {
 393                 /* XXX: these colours are right for GNOME; may need adjusting for other OS */
 394                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 395                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 396                 dc.SetPen (p);
 397                 dc.SetBrush (b);
 398                 dc.DrawRectangle (_out_size.width, 0, _panel_size.width - _out_size.width, _panel_size.height);
 399         }
 400
 401         if (_out_size.height < _panel_size.height) {
 402                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 403                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 404                 dc.SetPen (p);
 405                 dc.SetBrush (b);
 406                 int const gap = (_panel_size.height - _out_size.height) / 2;
 407                 dc.DrawRectangle (0, 0, _panel_size.width, gap);
 408                 dc.DrawRectangle (0, gap + _out_size.height + 1, _panel_size.width, gap + 1);
 409         }
 410
 411         if (_outline_content) {
 412                 wxPen p (wxColour (255, 0, 0), 2);
 413                 dc.SetPen (p);
 414                 dc.SetBrush (*wxTRANSPARENT_BRUSH);
 415                 dc.DrawRectangle (_inter_position.x, _inter_position.y + (_panel_size.height - _out_size.height) / 2, _inter_size.width, _inter_size.height);
 416         }
 417
 418         _state_timer.unset ();
 419 }
 420
 421 void
 422 FilmViewer::set_outline_content (bool o)
 423 {
 424         _outline_content = o;
 425         refresh_panel ();
 426 }
 427
 428 void
 429 FilmViewer::set_eyes (Eyes e)
 430 {
 431         _eyes = e;
 432         slow_refresh ();
 433 }
 434
 435 void
 436 FilmViewer::panel_sized (wxSizeEvent& ev)
 437 {
 438         _panel_size.width = ev.GetSize().GetWidth();
 439         _panel_size.height = ev.GetSize().GetHeight();
 440
 441         calculate_sizes ();
 442         if (!quick_refresh()) {
 443                 slow_refresh ();
 444         }
 445         PositionChanged ();
 446 }
 447
 448 void
 449 FilmViewer::calculate_sizes ()
 450 {
 451         if (!_film || !_player) {
 452                 return;
 453         }
 454
 455         Ratio const * container = _film->container ();
 456
 457         float const panel_ratio = _panel_size.ratio ();
 458         float const film_ratio = container ? container->ratio () : 1.78;
 459
 460         if (panel_ratio < film_ratio) {
 461                 /* panel is less widscreen than the film; clamp width */
 462                 _out_size.width = _panel_size.width;
 463                 _out_size.height = lrintf (_out_size.width / film_ratio);
 464         } else {
 465                 /* panel is more widescreen than the film; clamp height */
 466                 _out_size.height = _panel_size.height;
 467                 _out_size.width = lrintf (_out_size.height * film_ratio);
 468         }
 469
 470         /* Catch silly values */
 471         _out_size.width = max (64, _out_size.width);
 472         _out_size.height = max (64, _out_size.height);
 473
 474         _player->set_video_container_size (_out_size);
 475 }
 476
 477 void
 478 FilmViewer::start ()
 479 {
 480         if (!_film) {
 481                 return;
 482         }
 483
 484         optional<bool> v = PlaybackPermitted ();
 485         if (v && !*v) {
 486                 /* Computer says no */
 487                 return;
 488         }
 489
 490         if (_audio.isStreamOpen()) {
 491                 _audio.setStreamTime (_video_position.seconds());
 492                 _audio.startStream ();
 493         }
 494
 495         _playing = true;
 496         _dropped = 0;
 497         timer ();
 498         Started (position());
 499 }
 500
 501 bool
 502 FilmViewer::stop ()
 503 {
 504         if (_audio.isStreamRunning()) {
 505                 /* stop stream and discard any remaining queued samples */
 506                 _audio.abortStream ();
 507         }
 508
 509         if (!_playing) {
 510                 return false;
 511         }
 512
 513         _playing = false;
 514         Stopped (position());
 515         return true;
 516 }
 517
 518 void
 519 FilmViewer::player_change (ChangeType type, int property, bool frequent)
 520 {
 521         if (type != CHANGE_TYPE_DONE || frequent) {
 522                 return;
 523         }
 524
 525         if (_coalesce_player_changes) {
 526                 _pending_player_changes.push_back (property);
 527                 return;
 528         }
 529
 530         calculate_sizes ();
 531         bool refreshed = false;
 532         if (
 533                 property == VideoContentProperty::CROP ||
 534                 property == VideoContentProperty::SCALE ||
 535                 property == VideoContentProperty::FADE_IN ||
 536                 property == VideoContentProperty::FADE_OUT ||
 537                 property == VideoContentProperty::COLOUR_CONVERSION ||
 538                 property == PlayerProperty::VIDEO_CONTAINER_SIZE ||
 539                 property == PlayerProperty::FILM_CONTAINER
 540                 ) {
 541                 refreshed = quick_refresh ();
 542         }
 543
 544         if (!refreshed) {
 545                 slow_refresh ();
 546         }
 547         PositionChanged ();
 548 }
 549
 550 void
 551 FilmViewer::film_change (ChangeType type, Film::Property p)
 552 {
 553         if (type == CHANGE_TYPE_DONE && p == Film::AUDIO_CHANNELS) {
 554                 recreate_butler ();
 555         }
 556 }
 557
 558 /** Re-get the current frame slowly by seeking */
 559 void
 560 FilmViewer::slow_refresh ()
 561 {
 562         seek (_video_position, true);
 563 }
 564
 565 /** Try to re-get the current frame quickly by resetting the metadata
 566  *  in the PlayerVideo that we used last time.
 567  *  @return true if this was possible, false if not.
 568  */
 569 bool
 570 FilmViewer::quick_refresh ()
 571 {
 572         if (!_player_video.first) {
 573                 return false;
 574         }
 575
 576         if (!_player_video.first->reset_metadata (_film, _player->video_container_size(), _film->frame_size())) {
 577                 return false;
 578         }
 579
 580         display_player_video ();
 581         return true;
 582 }
 583
 584 void
 585 FilmViewer::seek (shared_ptr<Content> content, ContentTime t, bool accurate)
 586 {
 587         optional<DCPTime> dt = _player->content_time_to_dcp (content, t);
 588         if (dt) {
 589                 seek (*dt, accurate);
 590         }
 591 }
 592
 593 void
 594 FilmViewer::set_coalesce_player_changes (bool c)
 595 {
 596         _coalesce_player_changes = c;
 597
 598         if (!c) {
 599                 BOOST_FOREACH (int i, _pending_player_changes) {
 600                         player_change (CHANGE_TYPE_DONE, i, false);
 601                 }
 602                 _pending_player_changes.clear ();
 603         }
 604 }
 605
 606 void
 607 FilmViewer::seek (DCPTime t, bool accurate)
 608 {
 609         if (!_butler) {
 610                 return;
 611         }
 612
 613         if (t < DCPTime ()) {
 614                 t = DCPTime ();
 615         }
 616
 617         if (t >= _film->length ()) {
 618                 t = _film->length ();
 619         }
 620
 621         bool const was_running = stop ();
 622
 623         _closed_captions_dialog->clear ();
 624         _butler->seek (t, accurate);
 625         get ();
 626
 627         if (was_running) {
 628                 start ();
 629         }
 630
 631         PositionChanged ();
 632 }
 633
 634 void
 635 FilmViewer::config_changed (Config::Property p)
 636 {
 637 #ifdef DCPOMATIC_VARIANT_SWAROOP
 638         if (p == Config::PLAYER_BACKGROUND_IMAGE) {
 639                 refresh_panel ();
 640                 return;
 641         }
 642 #endif
 643
 644         if (p != Config::SOUND && p != Config::SOUND_OUTPUT) {
 645                 return;
 646         }
 647
 648         if (_audio.isStreamOpen ()) {
 649                 _audio.closeStream ();
 650         }
 651
 652         if (Config::instance()->sound() && _audio.getDeviceCount() > 0) {
 653                 unsigned int st = 0;
 654                 if (Config::instance()->sound_output()) {
 655                         while (st < _audio.getDeviceCount()) {
 656                                 if (_audio.getDeviceInfo(st).name == Config::instance()->sound_output().get()) {
 657                                         break;
 658                                 }
 659                                 ++st;
 660                         }
 661                         if (st == _audio.getDeviceCount()) {
 662                                 st = _audio.getDefaultOutputDevice();
 663                         }
 664                 } else {
 665                         st = _audio.getDefaultOutputDevice();
 666                 }
 667
 668                 _audio_channels = _audio.getDeviceInfo(st).outputChannels;
 669
 670                 RtAudio::StreamParameters sp;
 671                 sp.deviceId = st;
 672                 sp.nChannels = _audio_channels;
 673                 sp.firstChannel = 0;
 674                 try {
 675                         _audio.openStream (&sp, 0, RTAUDIO_FLOAT32, 48000, &_audio_block_size, &rtaudio_callback, this);
 676 #ifdef DCPOMATIC_USE_RTERROR
 677                 } catch (RtError& e) {
 678 #else
 679                 } catch (RtAudioError& e) {
 680 #endif
 681                         error_dialog (
 682                                 _panel,
 683                                 _("Could not set up audio output.  There will be no audio during the preview."), std_to_wx(e.what())
 684                                 );
 685                 }
 686                 recreate_butler ();
 687
 688         } else {
 689                 _audio_channels = 0;
 690                 recreate_butler ();
 691         }
 692 }
 693
 694 DCPTime
 695 FilmViewer::uncorrected_time () const
 696 {
 697         if (_audio.isStreamRunning ()) {
 698                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
 699         }
 700
 701         return _video_position;
 702 }
 703
 704 DCPTime
 705 FilmViewer::time () const
 706 {
 707         if (_audio.isStreamRunning ()) {
 708                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
 709                         DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
 710         }
 711
 712         return _video_position;
 713 }
 714
 715 int
 716 FilmViewer::audio_callback (void* out_p, unsigned int frames)
 717 {
 718         while (true) {
 719                 optional<DCPTime> t = _butler->get_audio (reinterpret_cast<float*> (out_p), frames);
 720                 if (!t || DCPTime(uncorrected_time() - *t) < one_video_frame()) {
 721                         /* There was an underrun or this audio is on time; carry on */
 722                         break;
 723                 }
 724                 /* The audio we just got was (very) late; drop it and get some more. */
 725         }
 726
 727         boost::mutex::scoped_lock lm (_latency_history_mutex, boost::try_to_lock);
 728         if (lm) {
 729                 _latency_history.push_back (_audio.getStreamLatency ());
 730                 if (_latency_history.size() > static_cast<size_t> (_latency_history_count)) {
 731                         _latency_history.pop_front ();
 732                 }
 733         }
 734
 735         return 0;
 736 }
 737
 738 Frame
 739 FilmViewer::average_latency () const
 740 {
 741         boost::mutex::scoped_lock lm (_latency_history_mutex);
 742         if (_latency_history.empty()) {
 743                 return 0;
 744         }
 745
 746         Frame total = 0;
 747         BOOST_FOREACH (Frame i, _latency_history) {
 748                 total += i;
 749         }
 750
 751         return total / _latency_history.size();
 752 }
 753
 754 void
 755 FilmViewer::set_dcp_decode_reduction (optional<int> reduction)
 756 {
 757         _dcp_decode_reduction = reduction;
 758         if (_player) {
 759                 _player->set_dcp_decode_reduction (reduction);
 760         }
 761 }
 762
 763 optional<int>
 764 FilmViewer::dcp_decode_reduction () const
 765 {
 766         return _dcp_decode_reduction;
 767 }
 768
 769 DCPTime
 770 FilmViewer::one_video_frame () const
 771 {
 772         return DCPTime::from_frames (1, _film->video_frame_rate());
 773 }
 774
 775 /** Open a dialog box showing our film's closed captions */
 776 void
 777 FilmViewer::show_closed_captions ()
 778 {
 779         _closed_captions_dialog->Show();
 780 }
 781
 782 void
 783 FilmViewer::seek_by (DCPTime by, bool accurate)
 784 {
 785         seek (_video_position + by, accurate);
 786 }
 787
 788 void
 789 FilmViewer::set_pad_black (bool p)
 790 {
 791         _pad_black = p;
 792 }