Show an explanatory message if the player is not performing very well (#1932).

6 files changed, 71 insertions, 12 deletions

diff --git a/src/lib/config.h b/src/lib/config.h
index 3371e48bf..0a48a00e1 100644
--- a/src/lib/config.h
+++ b/src/lib/config.h
@@ -392,6 +392,9 @@ public:
 		return _jump_to_selected;
 	}
 
+	/* This could be an enum class but we use the enum a lot to index _nagged
+	 * so it means a lot of casts.
+	 */
 	enum Nag {
 		NAG_DKDM_CONFIG,
 		NAG_ENCRYPTED_METADATA,
@@ -400,6 +403,7 @@ public:
 		NAG_IMPORT_DECRYPTION_CHAIN,
 		NAG_DELETE_DKDM,
 		NAG_32_ON_64,
+		NAG_TOO_MANY_DROPPED_FRAMES,
 		NAG_COUNT
 	};
 
diff --git a/src/wx/film_viewer.cc b/src/wx/film_viewer.cc
index b9e9bd533..14737d009 100644
--- a/src/wx/film_viewer.cc
+++ b/src/wx/film_viewer.cc
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2012-2019 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2012-2021 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -18,17 +18,20 @@
 
 */
 
+
 /** @file  src/film_viewer.cc
  *  @brief A wx widget to view a preview of a Film.
  */
 
-#include "film_viewer.h"
-#include "playhead_to_timecode_dialog.h"
-#include "playhead_to_frame_dialog.h"
-#include "wx_util.h"
+
 #include "closed_captions_dialog.h"
+#include "film_viewer.h"
 #include "gl_video_view.h"
+#include "nag_dialog.h"
+#include "playhead_to_frame_dialog.h"
+#include "playhead_to_timecode_dialog.h"
 #include "simple_video_view.h"
+#include "wx_util.h"
 #include "lib/film.h"
 #include "lib/ratio.h"
 #include "lib/util.h"
@@ -106,6 +109,7 @@ FilmViewer::FilmViewer (wxWindow* p)
 	}
 
 	_video_view->Sized.connect (boost::bind(&FilmViewer::video_view_sized, this));
+	_video_view->TooManyDropped.connect (boost::bind(&FilmViewer::too_many_frames_dropped, this));
 
 	set_film (shared_ptr<Film> ());
 
@@ -730,3 +734,22 @@ FilmViewer::image_changed (shared_ptr<PlayerVideo> pv)
 	emit (boost::bind(boost::ref(ImageChanged), pv));
 }
 
+
+void
+FilmViewer::too_many_frames_dropped ()
+{
+	if (!Config::instance()->nagged(Config::NAG_TOO_MANY_DROPPED_FRAMES)) {
+		stop ();
+	}
+
+	bool shown = NagDialog::maybe_nag (
+		panel(),
+		Config::NAG_TOO_MANY_DROPPED_FRAMES,
+		_("The player is dropping a lot of frames, so playback may not be accurate.\n\n"
+		  "<b>This does not necessarily mean that the DCP you are playing is defective!</b>\n\n"
+		  "You may be able to improve player performance by:\n"
+		  "• choosing 'decode at half resolution' or 'decode at quarter resolution' from the View menu\n"
+		  "• using a more powerful computer.\n"
+		 )
+		);
+}
diff --git a/src/wx/film_viewer.h b/src/wx/film_viewer.h
index 8024bb1bf..52b97f0f6 100644
--- a/src/wx/film_viewer.h
+++ b/src/wx/film_viewer.h
@@ -161,6 +161,7 @@ private:
 	void config_changed (Config::Property);
 	void film_length_change ();
 	void ui_finished ();
+	void too_many_frames_dropped ();
 
 	dcpomatic::DCPTime uncorrected_time () const;
 	Frame average_latency () const;
diff --git a/src/wx/nag_dialog.cc b/src/wx/nag_dialog.cc
index 466b80b6b..85f2d0110 100644
--- a/src/wx/nag_dialog.cc
+++ b/src/wx/nag_dialog.cc
@@ -70,7 +70,7 @@ NagDialog::maybe_nag (wxWindow* parent, Config::Nag nag, wxString message, bool
 		return false;
 	}
 
-	NagDialog* d = new NagDialog (parent, nag, message, can_cancel);
+	auto d = new NagDialog (parent, nag, message, can_cancel);
 	int const r = d->ShowModal();
 	d->Destroy ();
 
diff --git a/src/wx/video_view.cc b/src/wx/video_view.cc
index 5f44c37d6..387d4052f 100644
--- a/src/wx/video_view.cc
+++ b/src/wx/video_view.cc
@@ -25,12 +25,18 @@
 #include "lib/butler.h"
 #include "lib/dcpomatic_log.h"
 #include <boost/optional.hpp>
+#include <sys/time.h>
+
 
 using std::pair;
 using std::shared_ptr;
 using boost::optional;
 
 
+static constexpr int TOO_MANY_DROPPED_FRAMES = 20;
+static constexpr int TOO_MANY_DROPPED_PERIOD = 5.0;
+
+
 VideoView::VideoView (FilmViewer* viewer)
 	: _viewer (viewer)
 	, _state_timer ("viewer")
@@ -124,6 +130,7 @@ VideoView::start ()
 	boost::mutex::scoped_lock lm (_mutex);
 	_dropped = 0;
 	_errored = 0;
+	gettimeofday(&_dropped_check_period_start, nullptr);
 }
 
 
@@ -143,3 +150,26 @@ VideoView::reset_metadata (shared_ptr<const Film> film, dcp::Size player_video_c
 	return true;
 }
 
+
+void
+VideoView::add_dropped ()
+{
+	bool too_many = false;
+
+	{
+		boost::mutex::scoped_lock lm (_mutex);
+		++_dropped;
+		if (_dropped > TOO_MANY_DROPPED_FRAMES) {
+			struct timeval now;
+			gettimeofday (&now, nullptr);
+			double const elapsed = seconds(now) - seconds(_dropped_check_period_start);
+			too_many = elapsed < TOO_MANY_DROPPED_PERIOD;
+			_dropped = 0;
+			_dropped_check_period_start = now;
+		}
+	}
+
+	if (too_many) {
+		emit (boost::bind(boost::ref(TooManyDropped)));
+	}
+}
diff --git a/src/wx/video_view.h b/src/wx/video_view.h
index d3a15d38c..d7d60c21d 100644
--- a/src/wx/video_view.h
+++ b/src/wx/video_view.h
@@ -24,9 +24,10 @@
 
 
 #include "lib/dcpomatic_time.h"
+#include "lib/exception_store.h"
+#include "lib/signaller.h"
 #include "lib/timer.h"
 #include "lib/types.h"
-#include "lib/exception_store.h"
 #include <boost/signals2.hpp>
 #include <boost/thread.hpp>
 
@@ -38,7 +39,7 @@ class Player;
 class PlayerVideo;
 
 
-class VideoView : public ExceptionStore
+class VideoView : public ExceptionStore, public Signaller
 {
 public:
 	VideoView (FilmViewer* viewer);
@@ -70,6 +71,8 @@ public:
 
 	/** Emitted from the GUI thread when our display changes in size */
 	boost::signals2::signal<void()> Sized;
+	/** Emitted from the GUI thread when a lot of frames are being dropped */
+	boost::signals2::signal<void()> TooManyDropped;
 
 
 	/* Accessors for FilmViewer */
@@ -143,10 +146,7 @@ protected:
 		return _player_video;
 	}
 
-	void add_dropped () {
-		boost::mutex::scoped_lock lm (_mutex);
-		++_dropped;
-	}
+	void add_dropped ();
 
 	void add_get () {
 		boost::mutex::scoped_lock lm (_mutex);
@@ -169,6 +169,7 @@ private:
 	bool _three_d = false;
 
 	int _dropped = 0;
+	struct timeval _dropped_check_period_start;
 	int _errored = 0;
 	int _gets = 0;
 };