src/wx/film_viewer.cc

   1 /*
   2     Copyright (C) 2012-2019 Carl Hetherington <cth@carlh.net>
   3
   4     This file is part of DCP-o-matic.
   5
   6     DCP-o-matic is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     DCP-o-matic is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.
  18
  19 */
  20
  21 /** @file  src/film_viewer.cc
  22  *  @brief A wx widget to view a preview of a Film.
  23  */
  24
  25 #include "film_viewer.h"
  26 #include "playhead_to_timecode_dialog.h"
  27 #include "playhead_to_frame_dialog.h"
  28 #include "wx_util.h"
  29 #include "closed_captions_dialog.h"
  30 #include "lib/film.h"
  31 #include "lib/ratio.h"
  32 #include "lib/util.h"
  33 #include "lib/job_manager.h"
  34 #include "lib/image.h"
  35 #include "lib/exceptions.h"
  36 #include "lib/examine_content_job.h"
  37 #include "lib/filter.h"
  38 #include "lib/player.h"
  39 #include "lib/player_video.h"
  40 #include "lib/video_content.h"
  41 #include "lib/video_decoder.h"
  42 #include "lib/timer.h"
  43 #include "lib/butler.h"
  44 #include "lib/log.h"
  45 #include "lib/config.h"
  46 #include "lib/compose.hpp"
  47 #include "lib/dcpomatic_log.h"
  48 extern "C" {
  49 #include <libavutil/pixfmt.h>
  50 }
  51 #include <dcp/exceptions.h>
  52 #include <wx/tglbtn.h>
  53 #include <iostream>
  54 #include <iomanip>
  55
  56 using std::string;
  57 using std::pair;
  58 using std::min;
  59 using std::max;
  60 using std::cout;
  61 using std::list;
  62 using std::bad_alloc;
  63 using std::make_pair;
  64 using std::exception;
  65 using boost::shared_ptr;
  66 using boost::dynamic_pointer_cast;
  67 using boost::weak_ptr;
  68 using boost::optional;
  69 using dcp::Size;
  70 using namespace dcpomatic;
  71
  72 static
  73 int
  74 rtaudio_callback (void* out, void *, unsigned int frames, double, RtAudioStreamStatus, void* data)
  75 {
  76         return reinterpret_cast<FilmViewer*>(data)->audio_callback (out, frames);
  77 }
  78
  79 FilmViewer::FilmViewer (wxWindow* p)
  80         : _gl_view (new GLView (p))
  81         , _coalesce_player_changes (false)
  82         , _audio (DCPOMATIC_RTAUDIO_API)
  83         , _audio_channels (0)
  84         , _audio_block_size (1024)
  85         , _playing (false)
  86         , _latency_history_count (0)
  87         , _dropped (0)
  88         , _closed_captions_dialog (new ClosedCaptionsDialog(p, this))
  89         , _outline_content (false)
  90         , _eyes (EYES_LEFT)
  91         , _pad_black (false)
  92 #ifdef DCPOMATIC_VARIANT_SWAROOP
  93         , _in_watermark (false)
  94         , _background_image (false)
  95 #endif
  96         , _state_timer ("viewer")
  97         , _gets (0)
  98 {
  99         _timer.Bind  (wxEVT_TIMER, boost::bind (&FilmViewer::timer, this));
 100
 101         set_film (shared_ptr<Film> ());
 102
 103         _config_changed_connection = Config::instance()->Changed.connect (bind (&FilmViewer::config_changed, this, _1));
 104         config_changed (Config::SOUND_OUTPUT);
 105 }
 106
 107 FilmViewer::~FilmViewer ()
 108 {
 109         stop ();
 110 }
 111
 112 void
 113 FilmViewer::set_film (shared_ptr<Film> film)
 114 {
 115         if (_film == film) {
 116                 return;
 117         }
 118
 119         _film = film;
 120         _video_position = DCPTime ();
 121         _player_video.first.reset ();
 122         _player_video.second = DCPTime ();
 123
 124         _frame.reset ();
 125         _closed_captions_dialog->clear ();
 126
 127         if (!_film) {
 128                 _player.reset ();
 129                 recreate_butler ();
 130                 _frame.reset ();
 131                 refresh_panel ();
 132                 return;
 133         }
 134
 135         try {
 136                 _player.reset (new Player (_film, _film->playlist ()));
 137                 _player->set_fast ();
 138                 if (_dcp_decode_reduction) {
 139                         _player->set_dcp_decode_reduction (_dcp_decode_reduction);
 140                 }
 141         } catch (bad_alloc) {
 142                 error_dialog (_gl_view, _("There is not enough free memory to do that."));
 143                 _film.reset ();
 144                 return;
 145         }
 146
 147         _player->set_always_burn_open_subtitles ();
 148         _player->set_play_referenced ();
 149
 150         _film->Change.connect (boost::bind (&FilmViewer::film_change, this, _1, _2));
 151         _player->Change.connect (boost::bind (&FilmViewer::player_change, this, _1, _2, _3));
 152
 153         /* Keep about 1 second's worth of history samples */
 154         _latency_history_count = _film->audio_frame_rate() / _audio_block_size;
 155
 156         recreate_butler ();
 157
 158         calculate_sizes ();
 159         slow_refresh ();
 160 }
 161
 162 void
 163 FilmViewer::recreate_butler ()
 164 {
 165         bool const was_running = stop ();
 166         _butler.reset ();
 167
 168         if (!_film) {
 169                 return;
 170         }
 171
 172         AudioMapping map = AudioMapping (_film->audio_channels(), _audio_channels);
 173
 174         if (_audio_channels != 2 || _film->audio_channels() < 3) {
 175                 for (int i = 0; i < min (_film->audio_channels(), _audio_channels); ++i) {
 176                         map.set (i, i, 1);
 177                 }
 178         } else {
 179                 /* Special case: stereo output, at least 3 channel input.
 180                    Map so that Lt = L(-3dB) + Ls(-3dB) + C(-6dB) + Lfe(-10dB)
 181                                Rt = R(-3dB) + Rs(-3dB) + C(-6dB) + Lfe(-10dB)
 182                 */
 183                 map.set (dcp::LEFT,   0, 1 / sqrt(2)); // L -> Lt
 184                 map.set (dcp::RIGHT,  1, 1 / sqrt(2)); // R -> Rt
 185                 map.set (dcp::CENTRE, 0, 1 / 2.0); // C -> Lt
 186                 map.set (dcp::CENTRE, 1, 1 / 2.0); // C -> Rt
 187                 map.set (dcp::LFE,    0, 1 / sqrt(10)); // Lfe -> Lt
 188                 map.set (dcp::LFE,    1, 1 / sqrt(10)); // Lfe -> Rt
 189                 map.set (dcp::LS,     0, 1 / sqrt(2)); // Ls -> Lt
 190                 map.set (dcp::RS,     1, 1 / sqrt(2)); // Rs -> Rt
 191         }
 192
 193         _butler.reset (new Butler(_player, map, _audio_channels, bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true));
 194         if (!Config::instance()->sound() && !_audio.isStreamOpen()) {
 195                 _butler->disable_audio ();
 196         }
 197
 198         _closed_captions_dialog->set_film_and_butler (_film, _butler);
 199
 200         if (was_running) {
 201                 start ();
 202         }
 203 }
 204
 205 void
 206 FilmViewer::refresh_panel ()
 207 {
 208         /* XXX */
 209 }
 210
 211 void
 212 FilmViewer::get ()
 213 {
 214         DCPOMATIC_ASSERT (_butler);
 215         ++_gets;
 216
 217         do {
 218                 Butler::Error e;
 219                 _player_video = _butler->get_video (&e);
 220                 if (!_player_video.first && e == Butler::AGAIN) {
 221                         signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
 222                         return;
 223                 }
 224         } while (
 225                 _player_video.first &&
 226                 _film->three_d() &&
 227                 _eyes != _player_video.first->eyes() &&
 228                 _player_video.first->eyes() != EYES_BOTH
 229                 );
 230
 231         _butler->rethrow ();
 232
 233         display_player_video ();
 234 }
 235
 236 void
 237 FilmViewer::display_player_video ()
 238 {
 239         if (!_player_video.first) {
 240                 _frame.reset ();
 241                 refresh_panel ();
 242                 return;
 243         }
 244
 245         if (_playing && (time() - _player_video.second) > one_video_frame()) {
 246                 /* Too late; just drop this frame before we try to get its image (which will be the time-consuming
 247                    part if this frame is J2K).
 248                 */
 249                 _video_position = _player_video.second;
 250                 ++_dropped;
 251                 return;
 252         }
 253
 254         /* In an ideal world, what we would do here is:
 255          *
 256          * 1. convert to XYZ exactly as we do in the DCP creation path.
 257          * 2. convert back to RGB for the preview display, compensating
 258          *    for the monitor etc. etc.
 259          *
 260          * but this is inefficient if the source is RGB.  Since we don't
 261          * (currently) care too much about the precise accuracy of the preview's
 262          * colour mapping (and we care more about its speed) we try to short-
 263          * circuit this "ideal" situation in some cases.
 264          *
 265          * The content's specified colour conversion indicates the colourspace
 266          * which the content is in (according to the user).
 267          *
 268          * PlayerVideo::image (bound to PlayerVideo::force) will take the source
 269          * image and convert it (from whatever the user has said it is) to RGB.
 270          */
 271
 272         _state_timer.set ("get image");
 273         _frame = _player_video.first->image (bind(&PlayerVideo::force, _1, AV_PIX_FMT_RGB24), false, true);
 274
 275         _state_timer.set ("ImageChanged");
 276         ImageChanged (_player_video.first);
 277         _state_timer.unset ();
 278
 279         _video_position = _player_video.second;
 280         _inter_position = _player_video.first->inter_position ();
 281         _inter_size = _player_video.first->inter_size ();
 282
 283         refresh_panel ();
 284
 285         _closed_captions_dialog->update (time());
 286 }
 287
 288 void
 289 FilmViewer::timer ()
 290 {
 291         if (!_film || !_playing) {
 292                 return;
 293         }
 294
 295         get ();
 296         PositionChanged ();
 297         DCPTime const next = _video_position + one_video_frame();
 298
 299         if (next >= _film->length()) {
 300                 stop ();
 301                 Finished ();
 302                 return;
 303         }
 304
 305         LOG_DEBUG_PLAYER("%1 -> %2; delay %3", next.seconds(), time().seconds(), max((next.seconds() - time().seconds()) * 1000, 1.0));
 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 #ifdef DCPOMATIC_VARIANT_SWAROOP
 318         XXX
 319         optional<boost::filesystem::path> bg = Config::instance()->player_background_image();
 320         if (bg) {
 321                 wxImage image (std_to_wx(bg->string()));
 322                 wxBitmap bitmap (image);
 323                 dc.DrawBitmap (bitmap, max(0, (_panel_size.width - image.GetSize().GetWidth()) / 2), max(0, (_panel_size.height - image.GetSize().GetHeight()) / 2));
 324                 return true;
 325         }
 326
 327         return false;
 328 }
 329 #else
 330 FilmViewer::maybe_draw_background_image (wxPaintDC &)
 331 {
 332         return false;
 333 }
 334 #endif
 335
 336 #if 0
 337 XXX
 338 void
 339 FilmViewer::paint_panel ()
 340 {
 341         _state_timer.set ("paint-panel");
 342
 343         wxPaintDC dc (_panel);
 344
 345 #ifdef DCPOMATIC_VARIANT_SWAROOP
 346         if (_background_image) {
 347                 dc.Clear ();
 348                 maybe_draw_background_image (dc);
 349                 _state_timer.unset ();
 350                 return;
 351         }
 352 #endif
 353
 354         if (!_out_size.width || !_out_size.height || !_film || !_frame || _out_size != _frame->size()) {
 355                 dc.Clear ();
 356         } else {
 357
 358                 wxImage frame (_out_size.width, _out_size.height, _frame->data()[0], true);
 359                 wxBitmap frame_bitmap (frame);
 360                 dc.DrawBitmap (frame_bitmap, 0, max(0, (_panel_size.height - _out_size.height) / 2));
 361
 362 #ifdef DCPOMATIC_VARIANT_SWAROOP
 363                 DCPTime const period = DCPTime::from_seconds(Config::instance()->player_watermark_period() * 60);
 364                 int64_t n = _video_position.get() / period.get();
 365                 DCPTime from(n * period.get());
 366                 DCPTime to = from + DCPTime::from_seconds(Config::instance()->player_watermark_duration() / 1000.0);
 367                 if (from <= _video_position && _video_position <= to) {
 368                         if (!_in_watermark) {
 369                                 _in_watermark = true;
 370                                 _watermark_x = rand() % _panel_size.width;
 371                                 _watermark_y = rand() % _panel_size.height;
 372                         }
 373                         dc.SetTextForeground(*wxWHITE);
 374                         string wm = Config::instance()->player_watermark_theatre();
 375                         boost::posix_time::ptime t = boost::posix_time::second_clock::local_time();
 376                         wm += "\n" + boost::posix_time::to_iso_extended_string(t);
 377                         dc.DrawText(std_to_wx(wm), _watermark_x, _watermark_y);
 378                 } else {
 379                         _in_watermark = false;
 380                 }
 381 #endif
 382         }
 383
 384         if (_out_size.width < _panel_size.width) {
 385                 /* XXX: these colours are right for GNOME; may need adjusting for other OS */
 386                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 387                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 388                 dc.SetPen (p);
 389                 dc.SetBrush (b);
 390                 dc.DrawRectangle (_out_size.width, 0, _panel_size.width - _out_size.width, _panel_size.height);
 391         }
 392
 393         if (_out_size.height < _panel_size.height) {
 394                 wxPen   p (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 395                 wxBrush b (_pad_black ? wxColour(0, 0, 0) : wxColour(240, 240, 240));
 396                 dc.SetPen (p);
 397                 dc.SetBrush (b);
 398                 int const gap = (_panel_size.height - _out_size.height) / 2;
 399                 dc.DrawRectangle (0, 0, _panel_size.width, gap);
 400                 dc.DrawRectangle (0, gap + _out_size.height + 1, _panel_size.width, gap + 1);
 401         }
 402
 403         if (_outline_content) {
 404                 wxPen p (wxColour (255, 0, 0), 2);
 405                 dc.SetPen (p);
 406                 dc.SetBrush (*wxTRANSPARENT_BRUSH);
 407                 dc.DrawRectangle (_inter_position.x, _inter_position.y + (_panel_size.height - _out_size.height) / 2, _inter_size.width, _inter_size.height);
 408         }
 409
 410         _state_timer.unset ();
 411 }
 412 #endif
 413
 414 void
 415 FilmViewer::set_outline_content (bool o)
 416 {
 417         _outline_content = o;
 418         refresh_panel ();
 419 }
 420
 421 void
 422 FilmViewer::set_eyes (Eyes e)
 423 {
 424         _eyes = e;
 425         slow_refresh ();
 426 }
 427
 428 #if 0
 429 XXX
 430 void
 431 FilmViewer::panel_sized (wxSizeEvent& ev)
 432 {
 433         _panel_size.width = ev.GetSize().GetWidth();
 434         _panel_size.height = ev.GetSize().GetHeight();
 435
 436         calculate_sizes ();
 437         if (!quick_refresh()) {
 438                 slow_refresh ();
 439         }
 440         PositionChanged ();
 441 }
 442 #endif
 443
 444 void
 445 FilmViewer::calculate_sizes ()
 446 {
 447         if (!_film || !_player) {
 448                 return;
 449         }
 450
 451         Ratio const * container = _film->container ();
 452
 453         float const view_ratio = float(_gl_view->GetSize().x) / _gl_view->GetSize().y;
 454         float const film_ratio = container ? container->ratio () : 1.78;
 455
 456         if (view_ratio < film_ratio) {
 457                 /* panel is less widscreen than the film; clamp width */
 458                 _out_size.width = _gl_view->GetSize().x;
 459                 _out_size.height = lrintf (_out_size.width / film_ratio);
 460         } else {
 461                 /* panel is more widescreen than the film; clamp height */
 462                 _out_size.height = _gl_view->GetSize().y;
 463                 _out_size.width = lrintf (_out_size.height * film_ratio);
 464         }
 465
 466         /* Catch silly values */
 467         _out_size.width = max (64, _out_size.width);
 468         _out_size.height = max (64, _out_size.height);
 469
 470         _player->set_video_container_size (_out_size);
 471 }
 472
 473 void
 474 FilmViewer::start ()
 475 {
 476         if (!_film) {
 477                 return;
 478         }
 479
 480         optional<bool> v = PlaybackPermitted ();
 481         if (v && !*v) {
 482                 /* Computer says no */
 483                 return;
 484         }
 485
 486         if (_audio.isStreamOpen()) {
 487                 _audio.setStreamTime (_video_position.seconds());
 488                 _audio.startStream ();
 489         }
 490
 491         _playing = true;
 492         _dropped = 0;
 493         timer ();
 494         Started (position());
 495 }
 496
 497 bool
 498 FilmViewer::stop ()
 499 {
 500         if (_audio.isStreamRunning()) {
 501                 /* stop stream and discard any remaining queued samples */
 502                 _audio.abortStream ();
 503         }
 504
 505         if (!_playing) {
 506                 return false;
 507         }
 508
 509         _playing = false;
 510         Stopped (position());
 511         return true;
 512 }
 513
 514 void
 515 FilmViewer::player_change (ChangeType type, int property, bool frequent)
 516 {
 517         if (type != CHANGE_TYPE_DONE || frequent) {
 518                 return;
 519         }
 520
 521         if (_coalesce_player_changes) {
 522                 _pending_player_changes.push_back (property);
 523                 return;
 524         }
 525
 526         calculate_sizes ();
 527         bool refreshed = false;
 528         if (
 529                 property == VideoContentProperty::CROP ||
 530                 property == VideoContentProperty::SCALE ||
 531                 property == VideoContentProperty::FADE_IN ||
 532                 property == VideoContentProperty::FADE_OUT ||
 533                 property == VideoContentProperty::COLOUR_CONVERSION ||
 534                 property == PlayerProperty::VIDEO_CONTAINER_SIZE ||
 535                 property == PlayerProperty::FILM_CONTAINER
 536                 ) {
 537                 refreshed = quick_refresh ();
 538         }
 539
 540         if (!refreshed) {
 541                 slow_refresh ();
 542         }
 543         PositionChanged ();
 544 }
 545
 546 void
 547 FilmViewer::film_change (ChangeType type, Film::Property p)
 548 {
 549         if (type == CHANGE_TYPE_DONE && p == Film::AUDIO_CHANNELS) {
 550                 recreate_butler ();
 551         }
 552 }
 553
 554 /** Re-get the current frame slowly by seeking */
 555 void
 556 FilmViewer::slow_refresh ()
 557 {
 558         seek (_video_position, true);
 559 }
 560
 561 /** Try to re-get the current frame quickly by resetting the metadata
 562  *  in the PlayerVideo that we used last time.
 563  *  @return true if this was possible, false if not.
 564  */
 565 bool
 566 FilmViewer::quick_refresh ()
 567 {
 568         if (!_player_video.first) {
 569                 return false;
 570         }
 571
 572         if (!_player_video.first->reset_metadata (_film, _player->video_container_size(), _film->frame_size())) {
 573                 return false;
 574         }
 575
 576         display_player_video ();
 577         return true;
 578 }
 579
 580 void
 581 FilmViewer::seek (shared_ptr<Content> content, ContentTime t, bool accurate)
 582 {
 583         optional<DCPTime> dt = _player->content_time_to_dcp (content, t);
 584         if (dt) {
 585                 seek (*dt, accurate);
 586         }
 587 }
 588
 589 void
 590 FilmViewer::set_coalesce_player_changes (bool c)
 591 {
 592         _coalesce_player_changes = c;
 593
 594         if (!c) {
 595                 BOOST_FOREACH (int i, _pending_player_changes) {
 596                         player_change (CHANGE_TYPE_DONE, i, false);
 597                 }
 598                 _pending_player_changes.clear ();
 599         }
 600 }
 601
 602 void
 603 FilmViewer::seek (DCPTime t, bool accurate)
 604 {
 605         if (!_butler) {
 606                 return;
 607         }
 608
 609         if (t < DCPTime ()) {
 610                 t = DCPTime ();
 611         }
 612
 613         if (t >= _film->length ()) {
 614                 t = _film->length ();
 615         }
 616
 617         bool const was_running = stop ();
 618
 619         _closed_captions_dialog->clear ();
 620         _butler->seek (t, accurate);
 621         get ();
 622
 623         if (was_running) {
 624                 start ();
 625         }
 626
 627         PositionChanged ();
 628 }
 629
 630 void
 631 FilmViewer::config_changed (Config::Property p)
 632 {
 633 #ifdef DCPOMATIC_VARIANT_SWAROOP
 634         if (p == Config::PLAYER_BACKGROUND_IMAGE) {
 635                 refresh_panel ();
 636                 return;
 637         }
 638 #endif
 639
 640         if (p != Config::SOUND && p != Config::SOUND_OUTPUT) {
 641                 return;
 642         }
 643
 644         if (_audio.isStreamOpen ()) {
 645                 _audio.closeStream ();
 646         }
 647
 648         if (Config::instance()->sound() && _audio.getDeviceCount() > 0) {
 649                 unsigned int st = 0;
 650                 if (Config::instance()->sound_output()) {
 651                         while (st < _audio.getDeviceCount()) {
 652                                 if (_audio.getDeviceInfo(st).name == Config::instance()->sound_output().get()) {
 653                                         break;
 654                                 }
 655                                 ++st;
 656                         }
 657                         if (st == _audio.getDeviceCount()) {
 658                                 st = _audio.getDefaultOutputDevice();
 659                         }
 660                 } else {
 661                         st = _audio.getDefaultOutputDevice();
 662                 }
 663
 664                 _audio_channels = _audio.getDeviceInfo(st).outputChannels;
 665
 666                 RtAudio::StreamParameters sp;
 667                 sp.deviceId = st;
 668                 sp.nChannels = _audio_channels;
 669                 sp.firstChannel = 0;
 670                 try {
 671                         _audio.openStream (&sp, 0, RTAUDIO_FLOAT32, 48000, &_audio_block_size, &rtaudio_callback, this);
 672 #ifdef DCPOMATIC_USE_RTERROR
 673                 } catch (RtError& e) {
 674 #else
 675                 } catch (RtAudioError& e) {
 676 #endif
 677                         error_dialog (
 678                                 _gl_view,
 679                                 _("Could not set up audio output.  There will be no audio during the preview."), std_to_wx(e.what())
 680                                 );
 681                 }
 682                 recreate_butler ();
 683
 684         } else {
 685                 _audio_channels = 0;
 686                 recreate_butler ();
 687         }
 688 }
 689
 690 DCPTime
 691 FilmViewer::uncorrected_time () const
 692 {
 693         if (_audio.isStreamRunning ()) {
 694                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
 695         }
 696
 697         return _video_position;
 698 }
 699
 700 DCPTime
 701 FilmViewer::time () const
 702 {
 703         if (_audio.isStreamRunning ()) {
 704                 return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
 705                         DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
 706         }
 707
 708         return _video_position;
 709 }
 710
 711 int
 712 FilmViewer::audio_callback (void* out_p, unsigned int frames)
 713 {
 714         while (true) {
 715                 optional<DCPTime> t = _butler->get_audio (reinterpret_cast<float*> (out_p), frames);
 716                 if (!t || DCPTime(uncorrected_time() - *t) < one_video_frame()) {
 717                         /* There was an underrun or this audio is on time; carry on */
 718                         break;
 719                 }
 720                 /* The audio we just got was (very) late; drop it and get some more. */
 721         }
 722
 723         boost::mutex::scoped_lock lm (_latency_history_mutex, boost::try_to_lock);
 724         if (lm) {
 725                 _latency_history.push_back (_audio.getStreamLatency ());
 726                 if (_latency_history.size() > static_cast<size_t> (_latency_history_count)) {
 727                         _latency_history.pop_front ();
 728                 }
 729         }
 730
 731         return 0;
 732 }
 733
 734 Frame
 735 FilmViewer::average_latency () const
 736 {
 737         boost::mutex::scoped_lock lm (_latency_history_mutex);
 738         if (_latency_history.empty()) {
 739                 return 0;
 740         }
 741
 742         Frame total = 0;
 743         BOOST_FOREACH (Frame i, _latency_history) {
 744                 total += i;
 745         }
 746
 747         return total / _latency_history.size();
 748 }
 749
 750 void
 751 FilmViewer::set_dcp_decode_reduction (optional<int> reduction)
 752 {
 753         _dcp_decode_reduction = reduction;
 754         if (_player) {
 755                 _player->set_dcp_decode_reduction (reduction);
 756         }
 757 }
 758
 759 optional<int>
 760 FilmViewer::dcp_decode_reduction () const
 761 {
 762         return _dcp_decode_reduction;
 763 }
 764
 765 DCPTime
 766 FilmViewer::one_video_frame () const
 767 {
 768         return DCPTime::from_frames (1, _film->video_frame_rate());
 769 }
 770
 771 /** Open a dialog box showing our film's closed captions */
 772 void
 773 FilmViewer::show_closed_captions ()
 774 {
 775         _closed_captions_dialog->Show();
 776 }
 777
 778 void
 779 FilmViewer::seek_by (DCPTime by, bool accurate)
 780 {
 781         seek (_video_position + by, accurate);
 782 }
 783
 784 void
 785 FilmViewer::set_pad_black (bool p)
 786 {
 787         _pad_black = p;
 788 }