, _audio_channels (0)
, _audio_block_size (1024)
, _playing (false)
+ , _latency_history_count (0)
{
#ifndef __WXOSX__
_panel->SetDoubleBuffered (true);
_film->Changed.connect (boost::bind (&FilmViewer::film_changed, this, _1));
_player->Changed.connect (boost::bind (&FilmViewer::player_changed, this, _1));
+ /* Keep about 1 second's worth of history samples */
+ _latency_history_count = _film->audio_frame_rate() / _audio_block_size;
+
recreate_butler ();
calculate_sizes ();
FilmViewer::time () const
{
if (_audio.isStreamRunning ()) {
- return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ());
+ return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime ()) -
+ DCPTime::from_frames (average_latency(), _film->audio_frame_rate());
}
return _video_position;
FilmViewer::audio_callback (void* out_p, unsigned int frames)
{
_butler->get_audio (reinterpret_cast<float*> (out_p), frames);
+
+ 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();
+}
DCPTime time () const;
void start ();
bool stop ();
+ Frame average_latency () const;
boost::shared_ptr<Film> _film;
boost::shared_ptr<Player> _player;
bool _playing;
boost::shared_ptr<Butler> _butler;
+ std::list<Frame> _latency_history;
+ /** Mutex to protect _latency_history */
+ mutable boost::mutex _latency_history_mutex;
+ int _latency_history_count;
+
boost::signals2::scoped_connection _config_changed_connection;
};