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