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
  71 static
  72 int
  73 rtaudio_callback (void* out, void *, unsigned int frames, double, RtAudioStreamStatus, void* data)
  74 {
  75         return reinterpret_cast<FilmViewer*>(data)->audio_callback (out, frames);
  76 }
  77
  78 FilmViewer::FilmViewer (wxWindow* p)
  79         : _panel (new wxPanel (p))
  80         , _coalesce_player_changes (false)
  81         , _audio (DCPOMATIC_RTAUDIO_API)
  82         , _audio_channels (0)
  83         , _audio_block_size (1024)
  84         , _playing (false)
  85         , _latency_history_count (0)
  86         , _dropped (0)
  87         , _closed_captions_dialog (new ClosedCaptionsDialog(p, this))
  88         , _outline_content (false)
  89         , _eyes (EYES_LEFT)
  90         , _pad_black (false)
  91 #ifdef DCPOMATIC_VARIANT_SWAROOP
  92         , _in_watermark (false)
  93         , _background_image (false)
  94 #endif
  95 {
  96 #ifndef __WXOSX__
  97         _panel->SetDoubleBuffered (true);
  98 #endif
  99
 100         _panel->SetBackgroundStyle (wxBG_STYLE_PAINT);
 101         _panel->SetBackgroundColour (*wxBLACK);
 102
 103         _panel->Bind (wxEVT_PAINT, boost::bind (&FilmViewer::paint_panel, this));
 104         _panel->Bind (wxEVT_SIZE,  boost::bind (&FilmViewer::panel_sized, this, _1));
 105         _timer.Bind  (wxEVT_TIMER, boost::bind (&FilmViewer::timer, this));
 106
 107         set_film (shared_ptr<Film> ());
 108
 109         _config_changed_connection = Config::instance()->Changed.connect (bind (&FilmViewer::config_changed, this, _1));
 110         config_changed (Config::SOUND_OUTPUT);
 111 }
 112
 113 FilmViewer::~FilmViewer ()
 114 {
 115         stop ();
 116 }
 117
 118 void
 119 FilmViewer::set_film (shared_ptr<Film> film)
 120 {
 121         if (_film == film) {
 122                 return;
 123         }
 124
 125         _film = film;
 126         _video_position = DCPTime ();
 127         _player_video.first.reset ();
 128         _player_video.second = DCPTime ();
 129
 130         _frame.reset ();
 131         _closed_captions_dialog->clear ();
 132
 133         if (!_film) {
 134                 _player.reset ();
 135                 recreate_butler ();
 136                 _frame.reset ();
 137                 refresh_panel ();
 138                 return;
 139         }
 140
 141         try {
 142                 _player.reset (new Player (_film, _film->playlist ()));
 143                 _player->set_fast ();
 144                 if (_dcp_decode_reduction) {
 145                         _player->set_dcp_decode_reduction (_dcp_decode_reduction);
 146                 }
 147         } catch (bad_alloc &) {
 148                 error_dialog (_panel, _("There is not enough free memory to do that."));
 149                 _film.reset ();
 150                 return;
 151         }
 152
 153         _player->set_always_burn_open_subtitles ();
 154         _player->set_play_referenced ();
 155
 156         _film->Change.connect (boost::bind (&FilmViewer::film_change, this, _1, _2));
 157         _player->Change.connect (boost::bind (&FilmViewer::player_change, this, _1, _2, _3));
 158
 159         /* Keep about 1 second's worth of history samples */
 160         _latency_history_count = _film->audio_frame_rate() / _audio_block_size;
 161
 162         recreate_butler ();
 163
 164         calculate_sizes ();
 165         slow_refresh ();
 166 }
 167
 168 void
 169 FilmViewer::recreate_butler ()
 170 {
 171         bool const was_running = stop ();
 172         _butler.reset ();
 173
 174         if (!_film) {
 175                 return;
 176         }
 177
 178         AudioMapping map = AudioMapping (_film->audio_channels(), _audio_channels);
 179
 180         if (_audio_channels != 2 || _film->audio_channels() < 3) {
 181                 for (int i = 0; i < min (_film->audio_channels(), _audio_channels); ++i) {
 182                         map.set (i, i, 1);
 183                 }
 184         } else {
 185                 /* Special case: stereo output, at least 3 channel input.
 186                    Map so that Lt = L(-3dB) + Ls(-3dB) + C(-6dB) + Lfe(-10dB)
 187                                Rt = R(-3dB) + Rs(-3dB) + C(-6dB) + Lfe(-10dB)
 188                 */
 189                 if (_film->audio_channels() > 0) {
 190                         map.set (dcp::LEFT,   0, 1 / sqrt(2)); // L -> Lt
 191                 }
 192                 if (_film->audio_channels() > 1) {
 193                         map.set (dcp::RIGHT,  1, 1 / sqrt(2)); // R -> Rt
 194                 }
 195                 if (_film->audio_channels() > 2) {
 196                         map.set (dcp::CENTRE, 0, 1 / 2.0); // C -> Lt
 197                         map.set (dcp::CENTRE, 1, 1 / 2.0); // C -> Rt
 198                 }
 199                 if (_film->audio_channels() > 3) {
 200                         map.set (dcp::LFE,    0, 1 / sqrt(10)); // Lfe -> Lt
 201                         map.set (dcp::LFE,    1, 1 / sqrt(10)); // Lfe -> Rt
 202                 }
 203                 if (_film->audio_channels() > 4) {
 204                         map.set (dcp::LS,     0, 1 / sqrt(2)); // Ls -> Lt
 205                 }
 206                 if (_film->audio_channels() > 5) {
 207                         map.set (dcp::RS,     1, 1 / sqrt(2)); // Rs -> Rt
 208                 }
 209         }
 210
 211         _butler.reset (new Butler(_player, map, _audio_channels, bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true));
 212         if (!Config::instance()->sound() && !_audio.isStreamOpen()) {
 213                 _butler->disable_audio ();
 214         }
 215
 216         _closed_captions_dialog->set_film_and_butler (_film, _butler);
 217
 218         if (was_running) {
 219                 start ();
 220         }
 221 }
 222
 223 void
 224 FilmViewer::refresh_panel ()
 225 {
 226         _panel->Refresh ();
 227         _panel->Update ();
 228 }
 229
 230 void
 231 FilmViewer::get ()
 232 {
 233         DCPOMATIC_ASSERT (_butler);
 234
 235         do {
 236                 Butler::Error e;
 237                 _player_video = _butler->get_video (&e);
 238                 if (!_player_video.first && e == Butler::AGAIN) {
 239                         signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
 240                         return;
 241                 }
 242         } while (
 243                 _player_video.first &&
 244                 _film->three_d() &&
 245                 _eyes != _player_video.first->eyes() &&
 246                 _player_video.first->eyes() != EYES_BOTH
 247                 );
 248
 249         try {
 250                 _butler->rethrow ();
 251         } catch (DecodeError& e) {
 252                 error_dialog (_panel, e.what());
 253         }
 254
 255         display_player_video ();
 256 }
 257
 258 void
 259 FilmViewer::display_player_video ()
 260 {
 261         if (!_player_video.first) {
 262                 _frame.reset ();
 263                 refresh_panel ();
 264                 return;
 265         }
 266
 267         if (_playing && (time() - _player_video.second) > one_video_frame()) {
 268                 /* Too late; just drop this frame before we try to get its image (which will be the time-consuming
 269                    part if this frame is J2K).
 270                 */
 271                 _video_position = _player_video.second;
 272                 ++_dropped;
 273                 return;
 274         }
 275
 276         /* In an ideal world, what we would do here is:
 277          *
 278          * 1. convert to XYZ exactly as we do in the DCP creation path.
 279          * 2. convert back to RGB for the preview display, compensating
 280          *    for the monitor etc. etc.
 281          *
 282          * but this is inefficient if the source is RGB.  Since we don't
 283          * (currently) care too much about the precise accuracy of the preview's
 284          * colour mapping (and we care more about its speed) we try to short-
 285          * circuit this "ideal" situation in some cases.
 286          *
 287          * The content's specified colour conversion indicates the colourspace
 288          * which the content is in (according to the user).
 289          *
 290          * PlayerVideo::image (bound to PlayerVideo::force) will take the source
 291          * image and convert it (from whatever the user has said it is) to RGB.
 292          */
 293
 294         _frame = _player_video.first->image (bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true);
 295
 296         ImageChanged (_player_video.first);
 297
 298         _video_position = _player_video.second;
 299         _inter_position = _player_video.first->inter_position ();
 300         _inter_size = _player_video.first->inter_size ();
 301
 302         refresh_panel ();
 303
 304         _closed_captions_dialog->update (time());
 305 }
 306
 307 void
 308 FilmViewer::timer ()
 309 {
 310         if (!_film || !_playing) {
 311                 return;
 312         }
 313
 314         get ();
 315         PositionChanged ();
 316         DCPTime const next = _video_position + one_video_frame();
 317
 318         if (next >= _film->length()) {
 319                 stop ();
 320                 Finished ();
 321                 return;
 322         }
 323
 324         LOG_DEBUG_PLAYER("%1 -> %2; delay %3", next.seconds(), time().seconds(), max((next.seconds() - time().seconds()) * 1000, 1.0));
 325         _timer.Start (max ((next.seconds() - time().seconds()) * 1000, 1.0), wxTIMER_ONE_SHOT);
 326
 327         if (_butler) {
 328                 _butler->rethrow ();
 329         }
 330 }
 331
 332 bool
 333 #ifdef DCPOMATIC_VARIANT_SWAROOP
 334 FilmViewer::maybe_draw_background_image (wxPaintDC& dc)
 335 {
 336         optional<boost::filesystem::path> bg = Config::instance()->player_background_image();
 337         if (bg) {
 338                 wxImage image (std_to_wx(bg->string()));
 339                 wxBitmap bitmap (image);
 340                 dc.DrawBitmap (bitmap, max(0, (_panel_size.width - image.GetSize().GetWidth()) / 2), max(0, (_panel_size.height - image.GetSize().GetHeight()) / 2));
 341                 return true;
 342         }
 343
 344         return false;
 345 }
 346 #else
 347 FilmViewer::maybe_draw_background_image (wxPaintDC &)
 348 {
 349         return false;
 350 }
 351 #endif
 352
 353 void
 354 FilmViewer::paint_panel ()
 355 {
 356         wxPaintDC dc (_panel);
 357
 358 #ifdef DCPOMATIC_VARIANT_SWAROOP
 359         if (_background_image) {
 360                 dc.Clear ();
 361                 maybe_draw_background_image (dc);
 362                 return;
 363         }
 364 #endif
 365
 366         if (!_out_size.width || !_out_size.height || !_film || !_frame || _out_size != _frame->size()) {
 367                 dc.Clear ();
 368         } else {
 369
 370                 wxImage frame (_out_size.width, _out_size.height, _frame->data()[0], true);
 371                 wxBitmap frame_bitmap (frame);
 372                 dc.DrawBitmap (frame_bitmap, 0, max(0, (_panel_size.height - _out_size.height) / 2));
 373
 374 #ifdef DCPOMATIC_VARIANT_SWAROOP
 375                 DCPTime const period = DCPTime::from_seconds(Config::instance()->player_watermark_period() * 60);
 376                 int64_t n = _video_position.get() / period.get();
 377                 DCPTime from(n * period.get());
 378                 DCPTime to = from + DCPTime::from_seconds(Config::instance()->player_watermark_duration() / 1000.0);
 379                 if (from <= _video_position && _video_position <= to) {
 380                         if (!_in_watermark) {
 381                                 _in_watermark = true;
 382                                 _watermark_x = rand() % _panel_size.width;
 383                                 _watermark_y = rand() % _panel_size.height;
 384                         }
 385                         dc.SetTextForeground(*wxWHITE);
 386                         string wm = Config::instance()->player_watermark_theatre();
 387                         boost::posix_time::ptime t = boost::posix_time::second_clock::local_time();
 388                         wm += "\n" + boost::posix_time::to_iso_extended_string(t);
 389                         dc.DrawText(std_to_wx(wm), _watermark_x, _watermark_y);
 390                 } else {
 391                         _in_watermark = false;
 392                 }
 393 #endif
 394         }
 395
 396         if (_out_size.width < _panel_size.width) {
 397                 /* XXX: these colours are right for GNOME; may need adjusting for other OS */
 398                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 399                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 400                 dc.SetPen (p);
 401                 dc.SetBrush (b);
 402                 dc.DrawRectangle (_out_size.width, 0, _panel_size.width - _out_size.width, _panel_size.height);
 403         }
 404
 405         if (_out_size.height < _panel_size.height) {
 406                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 407                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 408                 dc.SetPen (p);
 409                 dc.SetBrush (b);
 410                 int const gap = (_panel_size.height - _out_size.height) / 2;
 411                 dc.DrawRectangle (0, 0, _panel_size.width, gap);
 412                 dc.DrawRectangle (0, gap + _out_size.height + 1, _panel_size.width, gap + 1);
 413         }
 414
 415         if (_outline_content) {
 416                 wxPen p (wxColour (255, 0, 0), 2);
 417                 dc.SetPen (p);
 418                 dc.SetBrush (*wxTRANSPARENT_BRUSH);
 419                 dc.DrawRectangle (_inter_position.x, _inter_position.y + (_panel_size.height - _out_size.height) / 2, _inter_size.width, _inter_size.height);
 420         }
 421 }
 422
 423 void
 424 FilmViewer::set_outline_content (bool o)
 425 {
 426         _outline_content = o;
 427         refresh_panel ();
 428 }
 429
 430 void
 431 FilmViewer::set_eyes (Eyes e)
 432 {
 433         _eyes = e;
 434         slow_refresh ();
 435 }
 436
 437 void
 438 FilmViewer::panel_sized (wxSizeEvent& ev)
 439 {
 440         _panel_size.width = ev.GetSize().GetWidth();
 441         _panel_size.height = ev.GetSize().GetHeight();
 442
 443         calculate_sizes ();
 444         if (!quick_refresh()) {
 445                 slow_refresh ();
 446         }
 447         PositionChanged ();
 448 }
 449
 450 void
 451 FilmViewer::calculate_sizes ()
 452 {
 453         if (!_film || !_player) {
 454                 return;
 455         }
 456
 457         Ratio const * container = _film->container ();
 458
 459         float const panel_ratio = _panel_size.ratio ();
 460         float const film_ratio = container ? container->ratio () : 1.78;
 461
 462         if (panel_ratio < film_ratio) {
 463                 /* panel is less widscreen than the film; clamp width */
 464                 _out_size.width = _panel_size.width;
 465                 _out_size.height = lrintf (_out_size.width / film_ratio);
 466         } else {
 467                 /* panel is more widescreen than the film; clamp height */
 468                 _out_size.height = _panel_size.height;
 469                 _out_size.width = lrintf (_out_size.height * film_ratio);
 470         }
 471
 472         /* Catch silly values */
 473         _out_size.width = max (64, _out_size.width);
 474         _out_size.height = max (64, _out_size.height);
 475
 476         _player->set_video_container_size (_out_size);
 477 }
 478
 479 void
 480 FilmViewer::start ()
 481 {
 482         if (!_film) {
 483                 return;
 484         }
 485
 486         optional<bool> v = PlaybackPermitted ();
 487         if (v && !*v) {
 488                 /* Computer says no */
 489                 return;
 490         }
 491
 492         if (_audio.isStreamOpen()) {
 493                 _audio.setStreamTime (_video_position.seconds());
 494                 _audio.startStream ();
 495         }
 496
 497         _playing = true;
 498         _dropped = 0;
 499         timer ();
 500         Started (position());
 501 }
 502
 503 bool
 504 FilmViewer::stop ()
 505 {
 506         if (_audio.isStreamRunning()) {
 507                 /* stop stream and discard any remaining queued samples */
 508                 _audio.abortStream ();
 509         }
 510
 511         if (!_playing) {
 512                 return false;
 513         }
 514
 515         _playing = false;
 516         Stopped (position());
 517         return true;
 518 }
 519
 520 void
 521 FilmViewer::player_change (ChangeType type, int property, bool frequent)
 522 {
 523         if (type != CHANGE_TYPE_DONE || frequent) {
 524                 return;
 525         }
 526
 527         if (_coalesce_player_changes) {
 528                 _pending_player_changes.push_back (property);
 529                 return;
 530         }
 531
 532         calculate_sizes ();
 533         bool refreshed = false;
 534         if (
 535                 property == VideoContentProperty::CROP ||
 536                 property == VideoContentProperty::SCALE ||
 537                 property == VideoContentProperty::FADE_IN ||
 538                 property == VideoContentProperty::FADE_OUT ||
 539                 property == VideoContentProperty::COLOUR_CONVERSION ||
 540                 property == PlayerProperty::VIDEO_CONTAINER_SIZE ||
 541                 property == PlayerProperty::FILM_CONTAINER
 542                 ) {
 543                 refreshed = quick_refresh ();
 544         }
 545
 546         if (!refreshed) {
 547                 slow_refresh ();
 548         }
 549         PositionChanged ();
 550 }
 551
 552 void
 553 FilmViewer::film_change (ChangeType type, Film::Property p)
 554 {
 555         if (type == CHANGE_TYPE_DONE && p == Film::AUDIO_CHANNELS) {
 556                 recreate_butler ();
 557         }
 558 }
 559
 560 /** Re-get the current frame slowly by seeking */
 561 void
 562 FilmViewer::slow_refresh ()
 563 {
 564         seek (_video_position, true);
 565 }
 566
 567 /** Try to re-get the current frame quickly by resetting the metadata
 568  *  in the PlayerVideo that we used last time.
 569  *  @return true if this was possible, false if not.
 570  */
 571 bool
 572 FilmViewer::quick_refresh ()
 573 {
 574         if (!_player_video.first) {
 575                 return false;
 576         }
 577
 578         if (!_player_video.first->reset_metadata (_film, _player->video_container_size(), _film->frame_size())) {
 579                 return false;
 580         }
 581
 582         display_player_video ();
 583         return true;
 584 }
 585
 586 void
 587 FilmViewer::seek (shared_ptr<Content> content, ContentTime t, bool accurate)
 588 {
 589         optional<DCPTime> dt = _player->content_time_to_dcp (content, t);
 590         if (dt) {
 591                 seek (*dt, accurate);
 592         }
 593 }
 594
 595 void
 596 FilmViewer::set_coalesce_player_changes (bool c)
 597 {
 598         _coalesce_player_changes = c;
 599
 600         if (!c) {
 601                 BOOST_FOREACH (int i, _pending_player_changes) {
 602                         player_change (CHANGE_TYPE_DONE, i, false);
 603                 }
 604                 _pending_player_changes.clear ();
 605         }
 606 }
 607
 608 void
 609 FilmViewer::seek (DCPTime t, bool accurate)
 610 {
 611         if (!_butler) {
 612                 return;
 613         }
 614
 615         if (t < DCPTime ()) {
 616                 t = DCPTime ();
 617         }
 618
 619         if (t >= _film->length ()) {
 620                 t = _film->length ();
 621         }
 622
 623         bool const was_running = stop ();
 624
 625         _closed_captions_dialog->clear ();
 626         _butler->seek (t, accurate);
 627         get ();
 628
 629         if (was_running) {
 630                 start ();
 631         }
 632
 633         PositionChanged ();
 634 }
 635
 636 void
 637 FilmViewer::config_changed (Config::Property p)
 638 {
 639 #ifdef DCPOMATIC_VARIANT_SWAROOP
 640         if (p == Config::PLAYER_BACKGROUND_IMAGE) {
 641                 refresh_panel ();
 642                 return;
 643         }
 644 #endif
 645
 646         if (p != Config::SOUND && p != Config::SOUND_OUTPUT) {
 647                 return;
 648         }
 649
 650         if (_audio.isStreamOpen ()) {
 651                 _audio.closeStream ();
 652         }
 653
 654         if (Config::instance()->sound() && _audio.getDeviceCount() > 0) {
 655                 unsigned int st = 0;
 656                 if (Config::instance()->sound_output()) {
 657                         while (st < _audio.getDeviceCount()) {
 658                                 if (_audio.getDeviceInfo(st).name == Config::instance()->sound_output().get()) {
 659                                         break;
 660                                 }
 661                                 ++st;
 662                         }
 663                         if (st == _audio.getDeviceCount()) {
 664                                 st = _audio.getDefaultOutputDevice();
 665                         }
 666                 } else {
 667                         st = _audio.getDefaultOutputDevice();
 668                 }
 669
 670                 _audio_channels = _audio.getDeviceInfo(st).outputChannels;
 671
 672                 RtAudio::StreamParameters sp;
 673                 sp.deviceId = st;
 674                 sp.nChannels = _audio_channels;
 675                 sp.firstChannel = 0;
 676                 try {
 677                         _audio.openStream (&sp, 0, RTAUDIO_FLOAT32, 48000, &_audio_block_size, &rtaudio_callback, this);
 678 #ifdef DCPOMATIC_USE_RTERROR
 679                 } catch (RtError& e) {
 680 #else
 681                 } catch (RtAudioError& e) {
 682 #endif
 683                         error_dialog (
 684                                 _panel,
 685                                 _("Could not set up audio output.  There will be no audio during the preview."), std_to_wx(e.what())
 686                                 );
 687                 }
 688                 recreate_butler ();
 689
 690         } else {
 691                 _audio_channels = 0;
 692                 recreate_butler ();
 693         }
 694 }
 695
 696 DCPTime
 697 FilmViewer::uncorrected_time () const
 698 {
 699         if (_audio.isStreamRunning ()) {
 700                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
 701         }
 702
 703         return _video_position;
 704 }
 705
 706 DCPTime
 707 FilmViewer::time () const
 708 {
 709         if (_audio.isStreamRunning ()) {
 710                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
 711                         DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
 712         }
 713
 714         return _video_position;
 715 }
 716
 717 int
 718 FilmViewer::audio_callback (void* out_p, unsigned int frames)
 719 {
 720         while (true) {
 721                 optional<DCPTime> t = _butler->get_audio (reinterpret_cast<float*> (out_p), frames);
 722                 if (!t || DCPTime(uncorrected_time() - *t) < one_video_frame()) {
 723                         /* There was an underrun or this audio is on time; carry on */
 724                         break;
 725                 }
 726                 /* The audio we just got was (very) late; drop it and get some more. */
 727         }
 728
 729         boost::mutex::scoped_lock lm (_latency_history_mutex, boost::try_to_lock);
 730         if (lm) {
 731                 _latency_history.push_back (_audio.getStreamLatency ());
 732                 if (_latency_history.size() > static_cast<size_t> (_latency_history_count)) {
 733                         _latency_history.pop_front ();
 734                 }
 735         }
 736
 737         return 0;
 738 }
 739
 740 Frame
 741 FilmViewer::average_latency () const
 742 {
 743         boost::mutex::scoped_lock lm (_latency_history_mutex);
 744         if (_latency_history.empty()) {
 745                 return 0;
 746         }
 747
 748         Frame total = 0;
 749         BOOST_FOREACH (Frame i, _latency_history) {
 750                 total += i;
 751         }
 752
 753         return total / _latency_history.size();
 754 }
 755
 756 void
 757 FilmViewer::set_dcp_decode_reduction (optional<int> reduction)
 758 {
 759         _dcp_decode_reduction = reduction;
 760         if (_player) {
 761                 _player->set_dcp_decode_reduction (reduction);
 762         }
 763 }
 764
 765 optional<int>
 766 FilmViewer::dcp_decode_reduction () const
 767 {
 768         return _dcp_decode_reduction;
 769 }
 770
 771 DCPTime
 772 FilmViewer::one_video_frame () const
 773 {
 774         return DCPTime::from_frames (1, _film->video_frame_rate());
 775 }
 776
 777 /** Open a dialog box showing our film's closed captions */
 778 void
 779 FilmViewer::show_closed_captions ()
 780 {
 781         _closed_captions_dialog->Show();
 782 }
 783
 784 void
 785 FilmViewer::seek_by (DCPTime by, bool accurate)
 786 {
 787         seek (_video_position + by, accurate);
 788 }
 789
 790 void
 791 FilmViewer::set_pad_black (bool p)
 792 {
 793         _pad_black = p;
 794 }