Timestamp audio emissions from butler and hence discard very late

[dcpomatic.git] / src / wx / film_viewer.cc

diff --git a/src/wx/film_viewer.cc b/src/wx/film_viewer.cc
index ef28018e96b0a960623ba665d4cc6344851f07b0..ce34b06b7122f56f2a12243c7cb448a3f333a6b9 100644 (file)
--- a/src/wx/film_viewer.cc
+++ b/src/wx/film_viewer.cc
@@ -881,6 +881,16 @@ FilmViewer::config_changed (Config::Property p)
        }
 }
 
+DCPTime
+FilmViewer::uncorrected_time () const
+{
+       if (_audio.isStreamRunning ()) {
+               return DCPTime::from_seconds (const_cast<RtAudio*>(&_audio)->getStreamTime());
+       }
+
+       return _video_position;
+}
+
 DCPTime
 FilmViewer::time () const
 {
@@ -895,7 +905,14 @@ FilmViewer::time () const
 int
 FilmViewer::audio_callback (void* out_p, unsigned int frames)
 {
-       _butler->get_audio (reinterpret_cast<float*> (out_p), 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) {