+#ifdef DCPOMATIC_VARIANT_SWAROOP
+ if (p == Config::PLAYER_BACKGROUND_IMAGE) {
+ refresh_view ();
+ return;
+ }
+#endif
+
+ if (p != Config::SOUND && p != Config::SOUND_OUTPUT) {
+ return;
+ }
+
+ if (_audio.isStreamOpen ()) {
+ _audio.closeStream ();
+ }
+
+ if (Config::instance()->sound() && _audio.getDeviceCount() > 0) {
+ unsigned int st = 0;
+ if (Config::instance()->sound_output()) {
+ while (st < _audio.getDeviceCount()) {
+ if (_audio.getDeviceInfo(st).name == Config::instance()->sound_output().get()) {
+ break;
+ }
+ ++st;
+ }
+ if (st == _audio.getDeviceCount()) {
+ st = _audio.getDefaultOutputDevice();
+ }
+ } else {
+ st = _audio.getDefaultOutputDevice();
+ }
+
+ _audio_channels = _audio.getDeviceInfo(st).outputChannels;
+
+ RtAudio::StreamParameters sp;
+ sp.deviceId = st;
+ sp.nChannels = _audio_channels;
+ sp.firstChannel = 0;
+ try {
+ _audio.openStream (&sp, 0, RTAUDIO_FLOAT32, 48000, &_audio_block_size, &rtaudio_callback, this);
+#ifdef DCPOMATIC_USE_RTERROR
+ } catch (RtError& e) {
+#else
+ } catch (RtAudioError& e) {
+#endif
+ error_dialog (
+ _video_view->get(),
+ _("Could not set up audio output. There will be no audio during the preview."), std_to_wx(e.what())
+ );
+ }
+ recreate_butler ();
+
+ } else {
+ _audio_channels = 0;
+ recreate_butler ();
+ }
+}
+
+DCPTime
+FilmViewer::uncorrected_time () const
+{
+ if (_audio.isStreamRunning ()) {
+ return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
+ }
+
+ return _video_position;
+}
+
+DCPTime
+FilmViewer::time () const
+{
+ if (_audio.isStreamRunning ()) {
+ return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
+ DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
+ }
+
+ return _video_position;
+}
+
+int
+FilmViewer::audio_callback (void* out_p, unsigned int frames)
+{
+ while (true) {
+ optional<DCPTime> t = _butler->get_audio (reinterpret_cast<float*> (out_p), frames);
+ if (!t || DCPTime(uncorrected_time() - *t) < one_video_frame()) {
+ /* There was an underrun or this audio is on time; carry on */
+ break;
+ }
+ /* The audio we just got was (very) late; drop it and get some more. */
+ }
+
+ boost::mutex::scoped_lock lm (_latency_history_mutex, boost::try_to_lock);
+ if (lm) {
+ _latency_history.push_back (_audio.getStreamLatency ());
+ if (_latency_history.size() > static_cast<size_t> (_latency_history_count)) {
+ _latency_history.pop_front ();
+ }
+ }
+
+ return 0;
+}
+
+Frame
+FilmViewer::average_latency () const
+{
+ boost::mutex::scoped_lock lm (_latency_history_mutex);
+ if (_latency_history.empty()) {
+ return 0;
+ }
+
+ Frame total = 0;
+ BOOST_FOREACH (Frame i, _latency_history) {
+ total += i;
+ }
+
+ return total / _latency_history.size();