Extract audio merging code from Player.

4 files changed, 122 insertions, 43 deletions

diff --git a/src/lib/audio_buffers.h b/src/lib/audio_buffers.h
index 6b57bd142..0950f5d67 100644
--- a/src/lib/audio_buffers.h
+++ b/src/lib/audio_buffers.h
@@ -17,6 +17,9 @@
 
 */
 
+#ifndef DVDOMATIC_AUDIO_BUFFERS_H
+#define DVDOMATIC_AUDIO_BUFFERS_H
+
 #include <boost/shared_ptr.hpp>
 
 /** @class AudioBuffers
@@ -72,3 +75,5 @@ private:
 	/** Audio data (so that, e.g. _data[2][6] is channel 2, sample 6) */
 	float** _data;
 };
+
+#endif
diff --git a/src/lib/audio_merger.h b/src/lib/audio_merger.h
new file mode 100644
index 000000000..126325a9d
--- /dev/null
+++ b/src/lib/audio_merger.h
@@ -0,0 +1,103 @@
+/*
+    Copyright (C) 2013 Carl Hetherington <cth@carlh.net>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include "audio_buffers.h"
+
+template <class T, class F>
+class AudioMerger
+{
+public:
+	AudioMerger (int channels, boost::function<F (T)> t_to_f, boost::function<T (F)> f_to_t)
+		: _buffers (new AudioBuffers (channels, 0))
+		, _next_emission (0)
+		, _t_to_f (t_to_f)
+		, _f_to_t (f_to_t)
+	{}
+
+	void push (boost::shared_ptr<const AudioBuffers> audio, T time)
+	{
+		if (time > _next_emission) {
+			/* We can emit some audio from our buffer; this is how many frames
+			   we are going to emit.
+			*/
+			F const to_emit = _t_to_f (time - _next_emission);
+			boost::shared_ptr<AudioBuffers> emit (new AudioBuffers (_buffers->channels(), to_emit));
+
+			/* And this is how many we will get from our buffer */
+			F const to_emit_from_buffers = min (to_emit, _buffers->frames ());
+
+			/* Copy the data that we have to the back end of `emit' */
+			emit->copy_from (_buffers.get(), to_emit_from_buffers, 0, to_emit - to_emit_from_buffers);
+
+			/* Silence any gap at the start */
+			emit->make_silent (0, to_emit - to_emit_from_buffers);
+
+			/* Emit that */
+			Audio (emit, _next_emission);
+
+			_next_emission += _f_to_t (to_emit);
+
+			/* And remove the data we've emitted from our buffers */
+			if (_buffers->frames() > to_emit_from_buffers) {
+				_buffers->move (to_emit_from_buffers, 0, _buffers->frames() - to_emit_from_buffers);
+			}
+			_buffers->set_frames (_buffers->frames() - to_emit_from_buffers);
+		}
+
+		/* Now accumulate the new audio into our buffers */
+		F frame = _t_to_f (time);
+		F after = max (_buffers->frames(), frame + audio->frames() - _t_to_f (_next_emission));
+		_buffers->ensure_size (after);
+		_buffers->accumulate_frames (audio.get(), 0, frame - _t_to_f (_next_emission), audio->frames ());
+		_buffers->set_frames (after);
+	}
+
+	F min (F a, int b)
+	{
+		if (a < b) {
+			return a;
+		}
+
+		return b;
+	}
+
+	F max (int a, F b)
+	{
+		if (a > b) {
+			return a;
+		}
+
+		return b;
+	}
+		
+	void flush ()
+	{
+		if (_buffers->frames() > 0) {
+			Audio (_buffers, _next_emission);
+		}
+	}
+	
+	boost::signals2::signal<void (boost::shared_ptr<const AudioBuffers>, T)> Audio;
+
+private:
+	boost::shared_ptr<AudioBuffers> _buffers;
+	T _next_emission;
+	boost::function<F (T)> _t_to_f;
+	boost::function<T (F)> _f_to_t;
+};
diff --git a/src/lib/player.cc b/src/lib/player.cc
index 647095793..dbc78b8d0 100644
--- a/src/lib/player.cc
+++ b/src/lib/player.cc
@@ -97,11 +97,12 @@ Player::Player (shared_ptr<const Film> f, shared_ptr<const Playlist> p)
 	, _have_valid_pieces (false)
 	, _video_position (0)
 	, _audio_position (0)
-	, _audio_buffers (f->audio_channels(), 0)
+	, _audio_merger (f->audio_channels(), bind (&Film::time_to_audio_frames, f.get(), _1), bind (&Film::audio_frames_to_time, f.get(), _1))
 {
 	_playlist->Changed.connect (bind (&Player::playlist_changed, this));
 	_playlist->ContentChanged.connect (bind (&Player::content_changed, this, _1, _2, _3));
 	_film->Changed.connect (bind (&Player::film_changed, this, _1));
+	_audio_merger.Audio.connect (bind (&Player::merger_process_audio, this, _1, _2));
 	set_video_container_size (_film->container()->size (_film->full_frame ()));
 }
 
@@ -318,52 +319,20 @@ Player::process_audio (weak_ptr<Piece> weak_piece, shared_ptr<const AudioBuffers
 		time = 0;
 	}
 
-	/* The time of this audio may indicate that some of our buffered audio is not going to
-	   be added to any more, so it can be emitted.
-	*/
-
-	if (time > _audio_position) {
-		/* We can emit some audio from our buffers; this is how many frames */
-		OutputAudioFrame const N = _film->time_to_audio_frames (time - _audio_position);
-		if (N > _audio_buffers.frames()) {
-			/* We need some extra silence before whatever is in the buffers */
-			_audio_buffers.ensure_size (N);
-			_audio_buffers.move (0, N - _audio_buffers.frames(), _audio_buffers.frames ());
-			_audio_buffers.make_silent (0, _audio_buffers.frames());
-			_audio_buffers.set_frames (N);
-		}
-		assert (N <= _audio_buffers.frames());
-
-		/* XXX: not convinced that a copy is necessary here */
-		shared_ptr<AudioBuffers> emit (new AudioBuffers (_audio_buffers.channels(), N));
-		emit->copy_from (&_audio_buffers, N, 0, 0);
-		Audio (emit, _audio_position);
-
-		_audio_position = piece->audio_position = _audio_position + _film->audio_frames_to_time (N);
-
-		/* And remove it from our buffers */
-		if (_audio_buffers.frames() > N) {
-			_audio_buffers.move (N, 0, _audio_buffers.frames() - N);
-		}
-		_audio_buffers.set_frames (_audio_buffers.frames() - N);
-	}
+	_audio_merger.push (audio, time);
+}
 
-	/* Now accumulate the new audio into our buffers */
-	_audio_buffers.ensure_size (_audio_buffers.frames() + audio->frames());
-	_audio_buffers.accumulate_frames (audio.get(), 0, 0, audio->frames ());
-	_audio_buffers.set_frames (_audio_buffers.frames() + audio->frames());
+void
+Player::merger_process_audio (shared_ptr<const AudioBuffers> audio, Time time)
+{
+	Audio (audio, time);
+	_audio_position += _film->audio_frames_to_time (audio->frames ());
 }
 
 void
 Player::flush ()
 {
-	if (_audio_buffers.frames() > 0) {
-		shared_ptr<AudioBuffers> emit (new AudioBuffers (_audio_buffers.channels(), _audio_buffers.frames()));
-		emit->copy_from (&_audio_buffers, _audio_buffers.frames(), 0, 0);
-		Audio (emit, _audio_position);
-		_audio_position += _film->audio_frames_to_time (_audio_buffers.frames ());
-		_audio_buffers.set_frames (0);
-	}
+	_audio_merger.flush ();
 
 	while (_video_position < _audio_position) {
 		emit_black ();
diff --git a/src/lib/player.h b/src/lib/player.h
index cd480dd1a..206254713 100644
--- a/src/lib/player.h
+++ b/src/lib/player.h
@@ -24,10 +24,11 @@
 #include <boost/shared_ptr.hpp>
 #include <boost/enable_shared_from_this.hpp>
 #include "playlist.h"
-#include "audio_buffers.h"
 #include "content.h"
 #include "film.h"
 #include "rect.h"
+#include "audio_merger.h"
+#include "audio_content.h"
 
 class Job;
 class Film;
@@ -93,6 +94,7 @@ private:
 	boost::shared_ptr<Resampler> resampler (boost::shared_ptr<AudioContent>, bool);
 	void film_changed (Film::Property);
 	void update_subtitle ();
+	void merger_process_audio (boost::shared_ptr<const AudioBuffers>, Time);
 
 	boost::shared_ptr<const Film> _film;
 	boost::shared_ptr<const Playlist> _playlist;
@@ -109,7 +111,7 @@ private:
 	/** The time after the last audio that we emitted */
 	Time _audio_position;
 
-	AudioBuffers _audio_buffers;
+	AudioMerger<Time, AudioContent::Frame> _audio_merger;
 
 	libdcp::Size _video_container_size;
 	boost::shared_ptr<Image> _black_frame;