Restore short-cutting of analysis gain updates.

If we have an analysis of one piece of content and
the gain changes we don't re-run the analysis, instead
applying a suitable `correction' in the UI.

1 files changed, 35 insertions, 3 deletions

diff --git a/src/wx/audio_dialog.cc b/src/wx/audio_dialog.cc
index cd59693ea..17d50ef69 100644
--- a/src/wx/audio_dialog.cc
+++ b/src/wx/audio_dialog.cc
@@ -27,10 +27,12 @@
 #include "lib/job_manager.h"
 #include <boost/filesystem.hpp>
 
+using std::cout;
 using boost::shared_ptr;
 using boost::bind;
 using boost::optional;
 using boost::const_pointer_cast;
+using boost::dynamic_pointer_cast;
 
 /** @param content Content to analyse, or 0 to analyse all of the film's audio */
 AudioDialog::AudioDialog (wxWindow* parent, shared_ptr<Film> film, shared_ptr<AudioContent> content)
@@ -109,7 +111,7 @@ AudioDialog::AudioDialog (wxWindow* parent, shared_ptr<Film> film, shared_ptr<Au
 	overall_sizer->Layout ();
 	overall_sizer->SetSizeHints (this);
 
-	_film_connection = film->ContentChanged.connect (boost::bind (&AudioDialog::try_to_load_analysis, this));
+	_film_connection = film->ContentChanged.connect (boost::bind (&AudioDialog::content_changed, this, _2));
 	SetTitle (_("DCP-o-matic audio"));
 
 	if (content) {
@@ -152,6 +154,7 @@ AudioDialog::try_to_load_analysis ()
         }
 
 	_plot->set_analysis (_analysis);
+	_plot->set_gain_correction (gain_correction ());
 	setup_peak_time ();
 
 	/* Set up some defaults if no check boxes are checked */
@@ -214,8 +217,18 @@ AudioDialog::channel_clicked (wxCommandEvent& ev)
 void
 AudioDialog::content_changed (int p)
 {
-	if (p == AudioContentProperty::AUDIO_GAIN || p == AudioContentProperty::AUDIO_STREAMS) {
+	if (p == AudioContentProperty::AUDIO_STREAMS) {
 		try_to_load_analysis ();
+	} else if (p == AudioContentProperty::AUDIO_GAIN) {
+		if (_playlist->content().size() == 1) {
+			/* We can use a short-cut to render the effect of this
+			   change, rather than recalculating everything.
+			*/
+			_plot->set_gain_correction (gain_correction ());
+			setup_peak_time ();
+		} else {
+			try_to_load_analysis ();
+		}
 	}
 }
 
@@ -250,7 +263,7 @@ AudioDialog::setup_peak_time ()
 		return;
 	}
 
-	float peak_dB = 20 * log10 (_analysis->peak().get());
+	float const peak_dB = 20 * log10 (_analysis->peak().get()) + gain_correction ();
 
 	_peak_time->SetLabel (
 		wxString::Format (
@@ -274,3 +287,22 @@ AudioDialog::Show (bool show)
 	try_to_load_analysis ();
 	return r;
 }
+
+/** @return gain correction in dB required to be added to raw gain values to render
+ *  the dialog correctly.
+ */
+float
+AudioDialog::gain_correction ()
+{
+	if (_playlist->content().size() == 1 && _analysis->analysis_gain ()) {
+		/* In this case we know that the analysis was of a single piece of content and
+		   we know that content's gain when the analysis was run.  Hence we can work out
+		   what correction is now needed to make it look `right'.
+		*/
+		shared_ptr<const AudioContent> ac = dynamic_pointer_cast<const AudioContent> (_playlist->content().front ());
+		DCPOMATIC_ASSERT (ac);
+		return ac->audio_gain() - _analysis->analysis_gain().get ();
+	}
+
+	return 0.0f;
+}