Multi-threaded decode of DCP when previewing.

7 files changed, 74 insertions, 21 deletions

diff --git a/src/lib/butler.cc b/src/lib/butler.cc
index 771c4e633..053d7c3bc 100644
--- a/src/lib/butler.cc
+++ b/src/lib/butler.cc
@@ -48,6 +48,7 @@ using boost::optional;
 Butler::Butler (weak_ptr<const Film> film, shared_ptr<Player> player, AudioMapping audio_mapping, int audio_channels)
 	: _film (film)
 	, _player (player)
+	, _prepare_work (new boost::asio::io_service::work (_prepare_service))
 	, _pending_seek_accurate (false)
 	, _finished (false)
 	, _died (false)
@@ -60,6 +61,13 @@ Butler::Butler (weak_ptr<const Film> film, shared_ptr<Player> player, AudioMappi
 	_player_audio_connection = _player->Audio.connect (bind (&Butler::audio, this, _1));
 	_player_changed_connection = _player->Changed.connect (bind (&Butler::player_changed, this));
 	_thread = new boost::thread (bind (&Butler::thread, this));
+
+	/* Create some threads to do work on the PlayerVideos we are creating; at present this is used to
+	   multi-thread JPEG2000 decoding.
+	*/
+	for (int i = 0; i < boost::thread::hardware_concurrency(); ++i) {
+		_prepare_pool.create_thread (bind (&boost::asio::io_service::run, &_prepare_service));
+	}
 }
 
 Butler::~Butler ()
@@ -69,6 +77,10 @@ Butler::~Butler ()
 		_stop_thread = true;
 	}
 
+	_prepare_work.reset ();
+	_prepare_pool.join_all ();
+	_prepare_service.stop ();
+
 	_thread->interrupt ();
 	try {
 		_thread->join ();
@@ -181,6 +193,16 @@ Butler::seek (DCPTime position, bool accurate)
 }
 
 void
+Butler::prepare (weak_ptr<PlayerVideo> weak_video) const
+{
+	shared_ptr<PlayerVideo> video = weak_video.lock ();
+	/* If the weak_ptr cannot be locked the video obviously no longer requires any work */
+	if (video) {
+		video->prepare ();
+	}
+}
+
+void
 Butler::video (shared_ptr<PlayerVideo> video, DCPTime time)
 {
 	{
@@ -191,6 +213,7 @@ Butler::video (shared_ptr<PlayerVideo> video, DCPTime time)
 		}
 	}
 
+	_prepare_service.post (bind (&Butler::prepare, this, weak_ptr<PlayerVideo>(video)));
 	_video.put (video, time);
 }
 
diff --git a/src/lib/butler.h b/src/lib/butler.h
index 9949ab79b..1e8947f9d 100644
--- a/src/lib/butler.h
+++ b/src/lib/butler.h
@@ -27,6 +27,7 @@
 #include <boost/thread.hpp>
 #include <boost/thread/condition.hpp>
 #include <boost/signals2.hpp>
+#include <boost/asio.hpp>
 
 class Film;
 class Player;
@@ -50,6 +51,7 @@ private:
 	void audio (boost::shared_ptr<AudioBuffers> audio);
 	void player_changed ();
 	bool should_run () const;
+	void prepare (boost::weak_ptr<PlayerVideo> video) const;
 
 	boost::weak_ptr<const Film> _film;
 	boost::shared_ptr<Player> _player;
@@ -58,6 +60,10 @@ private:
 	VideoRingBuffers _video;
 	AudioRingBuffers _audio;
 
+	boost::thread_group _prepare_pool;
+	boost::asio::io_service _prepare_service;
+	boost::shared_ptr<boost::asio::io_service::work> _prepare_work;
+
 	/** mutex to protect _pending_seek_position, _pending_seek_acurate, _finished, _died, _stop_thread */
 	boost::mutex _mutex;
 	boost::condition _summon;
diff --git a/src/lib/image_proxy.h b/src/lib/image_proxy.h
index d7bd7b0e6..f9a06d1b7 100644
--- a/src/lib/image_proxy.h
+++ b/src/lib/image_proxy.h
@@ -74,6 +74,10 @@ public:
 	virtual void send_binary (boost::shared_ptr<Socket>) const = 0;
 	/** @return true if our image is definitely the same as another, false if it is probably not */
 	virtual bool same (boost::shared_ptr<const ImageProxy>) const = 0;
+	/** Do any useful work that would speed up a subsequent call to ::image().
+	 *  This method may be called in a different thread to image().
+	 */
+	virtual void prepare (boost::optional<dcp::Size> = boost::optional<dcp::Size>()) const {}
 	virtual AVPixelFormat pixel_format () const = 0;
 };
 
diff --git a/src/lib/j2k_image_proxy.cc b/src/lib/j2k_image_proxy.cc
index f7e6dd5f4..9e68951e9 100644
--- a/src/lib/j2k_image_proxy.cc
+++ b/src/lib/j2k_image_proxy.cc
@@ -93,35 +93,45 @@ J2KImageProxy::J2KImageProxy (shared_ptr<cxml::Node> xml, shared_ptr<Socket> soc
 	socket->read (_data.data().get (), _data.size ());
 }
 
-shared_ptr<Image>
-J2KImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size> target_size) const
+void
+J2KImageProxy::prepare (optional<dcp::Size> target_size) const
 {
-	if (!_decompressed || target_size != _target_size) {
-		int reduce = 0;
+	boost::mutex::scoped_lock lm (_mutex);
 
-		while (target_size && (_size.width / pow(2, reduce)) > target_size->width && (_size.height / pow(2, reduce)) > target_size->height) {
-			++reduce;
-		}
+	if (_decompressed && target_size == _target_size) {
+		return;
+	}
 
-		--reduce;
-		reduce = max (0, reduce);
-		_decompressed = dcp::decompress_j2k (const_cast<uint8_t*> (_data.data().get()), _data.size (), reduce);
+	int reduce = 0;
 
-		if (_decompressed->precision(0) < 12) {
-			int const shift = 12 - _decompressed->precision (0);
-			for (int c = 0; c < 3; ++c) {
-				int* p = _decompressed->data (c);
-				for (int y = 0; y < _decompressed->size().height; ++y) {
-					for (int x = 0; x < _decompressed->size().width; ++x) {
-						*p++ <<= shift;
-					}
+	while (target_size && (_size.width / pow(2, reduce)) > target_size->width && (_size.height / pow(2, reduce)) > target_size->height) {
+		++reduce;
+	}
+
+	--reduce;
+	reduce = max (0, reduce);
+	_decompressed = dcp::decompress_j2k (const_cast<uint8_t*> (_data.data().get()), _data.size (), reduce);
+
+	if (_decompressed->precision(0) < 12) {
+		int const shift = 12 - _decompressed->precision (0);
+		for (int c = 0; c < 3; ++c) {
+			int* p = _decompressed->data (c);
+			for (int y = 0; y < _decompressed->size().height; ++y) {
+				for (int x = 0; x < _decompressed->size().width; ++x) {
+					*p++ <<= shift;
 				}
 			}
 		}
-
-		_target_size = target_size;
 	}
 
+	_target_size = target_size;
+}
+
+shared_ptr<Image>
+J2KImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size> target_size) const
+{
+	prepare (target_size);
+
 	shared_ptr<Image> image (new Image (_pixel_format, _decompressed->size(), true));
 
 	/* Copy data in whatever format (sRGB or XYZ) into our Image; I'm assuming
diff --git a/src/lib/j2k_image_proxy.h b/src/lib/j2k_image_proxy.h
index 41d68588f..3133aac20 100644
--- a/src/lib/j2k_image_proxy.h
+++ b/src/lib/j2k_image_proxy.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2015 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2015-2017 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -21,6 +21,7 @@
 #include "image_proxy.h"
 #include <dcp/util.h>
 #include <dcp/data.h>
+#include <boost/thread/mutex.hpp>
 
 namespace dcp {
 	class MonoPictureFrame;
@@ -44,6 +45,7 @@ public:
 	void send_binary (boost::shared_ptr<Socket>) const;
 	/** @return true if our image is definitely the same as another, false if it is probably not */
 	bool same (boost::shared_ptr<const ImageProxy>) const;
+	void prepare (boost::optional<dcp::Size> = boost::optional<dcp::Size>()) const;
 	AVPixelFormat pixel_format () const {
 		return _pixel_format;
 	}
@@ -68,4 +70,5 @@ private:
 	mutable boost::shared_ptr<dcp::OpenJPEGImage> _decompressed;
 	mutable boost::optional<dcp::Size> _target_size;
 	AVPixelFormat _pixel_format;
+	mutable boost::mutex _mutex;
 };
diff --git a/src/lib/player_video.cc b/src/lib/player_video.cc
index 6f0977e62..14291fc35 100644
--- a/src/lib/player_video.cc
+++ b/src/lib/player_video.cc
@@ -246,3 +246,9 @@ PlayerVideo::keep_xyz_or_rgb (AVPixelFormat p)
 {
 	return p == AV_PIX_FMT_XYZ12LE ? AV_PIX_FMT_XYZ12LE : AV_PIX_FMT_RGB48LE;
 }
+
+void
+PlayerVideo::prepare ()
+{
+	_in->prepare (_inter_size);
+}
diff --git a/src/lib/player_video.h b/src/lib/player_video.h
index 5017d0e3c..040145559 100644
--- a/src/lib/player_video.h
+++ b/src/lib/player_video.h
@@ -57,6 +57,7 @@ public:
 
 	void set_subtitle (PositionImage);
 
+	void prepare ();
 	boost::shared_ptr<Image> image (dcp::NoteHandler note, boost::function<AVPixelFormat (AVPixelFormat)> pixel_format, bool aligned, bool fast) const;
 
 	static AVPixelFormat always_rgb (AVPixelFormat);