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