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