Switch away from the many-constructor-arguments approach to a hopefully simpler API.

11 files changed, 173 insertions, 387 deletions

diff --git a/src/asset.cc b/src/asset.cc
index 6e4901b5..4e17f855 100644
--- a/src/asset.cc
+++ b/src/asset.cc
@@ -37,14 +37,14 @@ using namespace std;
 using namespace boost;
 using namespace libdcp;
 
-Asset::Asset (boost::filesystem::path directory, string file_name, int edit_rate, int intrinsic_duration)
+Asset::Asset (boost::filesystem::path directory, string file_name)
 	: _directory (directory)
 	, _file_name (file_name)
 	, _uuid (make_uuid ())
-	, _edit_rate (edit_rate)
+	, _edit_rate (0)
 	, _entry_point (0)
-	, _intrinsic_duration (intrinsic_duration)
-	, _duration (intrinsic_duration)
+	, _intrinsic_duration (0)
+	, _duration (0)
 {
 	if (_file_name.empty ()) {
 		_file_name = _uuid + ".xml";
diff --git a/src/asset.h b/src/asset.h
index 940ed548..ec1385e6 100644
--- a/src/asset.h
+++ b/src/asset.h
@@ -53,7 +53,7 @@ public:
 	 *  @param directory Directory where our XML or MXF file is.
 	 *  @param file_name Name of our file within directory, or empty to make one up based on UUID.
 	 */
-	Asset (boost::filesystem::path directory, std::string file_name = "", int edit_rate = 0, int intrinsic_duration = 0);
+	Asset (boost::filesystem::path directory, std::string file_name = "");
 
 	virtual ~Asset() {}
 
@@ -123,6 +123,10 @@ public:
 		_intrinsic_duration = d;
 	}
 
+	void set_edit_rate (int r) {
+		_edit_rate = r;
+	}
+
 	virtual bool equals (boost::shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, std::string)>) const;
 
 protected:
diff --git a/src/cpl.cc b/src/cpl.cc
index 5d57c7c7..48d08035 100644
--- a/src/cpl.cc
+++ b/src/cpl.cc
@@ -107,15 +107,13 @@ CPL::CPL (boost::filesystem::path directory, string file, list<PathAssetMap> ass
 
 		if (!(*i)->asset_list->main_stereoscopic_picture && p->edit_rate == p->frame_rate) {
 
-			pair<string, shared_ptr<const parse::AssetMapAsset> > asset = asset_from_id (asset_maps, p->id);
-
 			try {
-				picture.reset (new MonoPictureAsset (
-						       asset.first,
-						       asset.second->chunks.front()->path
-						       )
-					);
+				pair<string, shared_ptr<const parse::AssetMapAsset> > asset = asset_from_id (asset_maps, p->id);
 
+				picture.reset (new MonoPictureAsset (asset.first, asset.second->chunks.front()->path));
+
+				picture->read ();
+				picture->set_edit_rate (_fps);
 				picture->set_entry_point (p->entry_point);
 				picture->set_duration (p->duration);
 				if (p->key_id.length() > 9) {
@@ -132,14 +130,10 @@ CPL::CPL (boost::filesystem::path directory, string file, list<PathAssetMap> ass
 			try {
 				pair<string, shared_ptr<const parse::AssetMapAsset> > asset = asset_from_id (asset_maps, p->id);
 
-				picture.reset (new StereoPictureAsset (
-						       asset.first,
-						       asset.second->chunks.front()->path,
-						       _fps,
-						       p->duration
-						       )
-					);
+				picture.reset (new StereoPictureAsset (asset.first, asset.second->chunks.front()->path));
 
+				picture->read ();
+				picture->set_edit_rate (_fps);
 				picture->set_entry_point (p->entry_point);
 				picture->set_duration (p->duration);
 				if (p->key_id.length() > 9) {
@@ -160,14 +154,10 @@ CPL::CPL (boost::filesystem::path directory, string file, list<PathAssetMap> ass
 			try {
 				pair<string, shared_ptr<const parse::AssetMapAsset> > asset = asset_from_id (asset_maps, (*i)->asset_list->main_sound->id);
 			
-				sound.reset (new SoundAsset (
-						     asset.first,
-						     asset.second->chunks.front()->path
-						     )
-					);
-
+				sound.reset (new SoundAsset (asset.first, asset.second->chunks.front()->path));
 				shared_ptr<parse::MainSound> s = (*i)->asset_list->main_sound;
 
+				sound->read ();
 				sound->set_entry_point (s->entry_point);
 				sound->set_duration (s->duration);
 				if (s->key_id.length() > 9) {
@@ -185,11 +175,7 @@ CPL::CPL (boost::filesystem::path directory, string file, list<PathAssetMap> ass
 			
 			pair<string, shared_ptr<const parse::AssetMapAsset> > asset = asset_from_id (asset_maps, (*i)->asset_list->main_subtitle->id);
 
-			subtitle.reset (new SubtitleAsset (
-						asset.first,
-						asset.second->chunks.front()->path
-						)
-				);
+			subtitle.reset (new SubtitleAsset (asset.first, asset.second->chunks.front()->path));
 
 			subtitle->set_entry_point ((*i)->asset_list->main_subtitle->entry_point);
 			subtitle->set_duration ((*i)->asset_list->main_subtitle->duration);
diff --git a/src/mxf_asset.cc b/src/mxf_asset.cc
index 956d38f9..7bffc9f2 100644
--- a/src/mxf_asset.cc
+++ b/src/mxf_asset.cc
@@ -48,19 +48,11 @@ MXFAsset::MXFAsset (boost::filesystem::path directory, string file_name)
 	, _progress (0)
 	, _encryption_context (0)
 	, _decryption_context (0)
+	, _interop (false)
 {
 
 }
 
-MXFAsset::MXFAsset (boost::filesystem::path directory, string file_name, boost::signals2::signal<void (float)>* progress, int edit_rate, int intrinsic_duration) 
-	: Asset (directory, file_name, edit_rate, intrinsic_duration)
-	, _progress (progress)
-	, _encryption_context (0)
-	, _decryption_context (0)
-{
-	
-}
-
 MXFAsset::~MXFAsset ()
 {
 	delete _encryption_context;
diff --git a/src/mxf_asset.h b/src/mxf_asset.h
index e566c32c..b7144281 100644
--- a/src/mxf_asset.h
+++ b/src/mxf_asset.h
@@ -23,6 +23,7 @@
 #include <boost/signals2.hpp>
 #include "asset.h"
 #include "key.h"
+#include "metadata.h"
 
 namespace ASDCP {
 	class AESEncContext;
@@ -46,29 +47,12 @@ public:
 	 */
 	MXFAsset (boost::filesystem::path directory, std::string file_name);
 	
-	/** Construct an MXFAsset.
-	 *  This class will not write anything to disk in this constructor, but subclasses may.
-	 *
-	 *  @param directory Directory where MXF file is.
-	 *  @param file_name Name of MXF file.
-	 *  @param progress Signal to use to inform of progress, or 0.
-	 *  @param edit_rate Edit rate in frames per second (usually equal to the video frame rate).
-	 *  @param intrinsic_duration Duration of the whole asset in frames.
-	 */
-	MXFAsset (
-		boost::filesystem::path directory,
-		std::string file_name,
-		boost::signals2::signal<void (float)>* progress,
-		int edit_rate,
-		int intrinsic_duration
-		);
-
 	~MXFAsset ();
 
 	virtual bool equals (boost::shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, std::string)> note) const;
-
 	virtual void write_to_cpl (xmlpp::Element *, bool interop) const;
-
+	virtual std::string key_type () const = 0;
+	
 	/** Fill in a ADSCP::WriteInfo struct.
 	 *  @param w struct to fill in.
 	 *  @param uuid uuid to use.
@@ -76,6 +60,10 @@ public:
 	 */
 	void fill_writer_info (ASDCP::WriterInfo* w, std::string uuid, bool interop, MXFMetadata const & metadata);
 
+	void set_progress (boost::signals2::signal<void (float)>* progress) {
+		_progress = progress;
+	}
+
 	bool encrypted () const {
 		return !_key_id.empty ();
 	}
@@ -98,8 +86,22 @@ public:
 		return _encryption_context;
 	}
 
-	virtual std::string key_type () const = 0;
-	
+	void set_metadata (MXFMetadata m) {
+		_metadata = m;
+	}
+
+	MXFMetadata metadata () const {
+		return _metadata;
+	}
+
+	void set_interop (bool i) {
+		_interop = i;
+	}
+
+	bool interop () const {
+		return _interop;
+	}
+
 protected:
 	virtual std::string cpl_node_name () const = 0;
 	virtual std::pair<std::string, std::string> cpl_node_attribute (bool) const {
@@ -112,6 +114,8 @@ protected:
 	ASDCP::AESDecContext* _decryption_context;
 	std::string _key_id;
 	boost::optional<Key> _key;
+	MXFMetadata _metadata;
+	bool _interop;
 };
 
 }
diff --git a/src/picture_asset.cc b/src/picture_asset.cc
index 78d7576d..97fce2ab 100644
--- a/src/picture_asset.cc
+++ b/src/picture_asset.cc
@@ -54,57 +54,12 @@ using boost::dynamic_pointer_cast;
 using boost::lexical_cast;
 using namespace libdcp;
 
-PictureAsset::PictureAsset (
-	boost::filesystem::path directory, string mxf_name, boost::signals2::signal<void (float)>* progress, int fps, int intrinsic_duration, Size size
-	)
-	: MXFAsset (directory, mxf_name, progress, fps, intrinsic_duration)
-	, _size (size)
-{
-
-}
-
 PictureAsset::PictureAsset (boost::filesystem::path directory, string mxf_name)
 	: MXFAsset (directory, mxf_name)
 {
 
 }
 
-string
-MonoPictureAsset::cpl_node_name () const
-{
-	return "MainPicture";
-}
-
-int
-MonoPictureAsset::edit_rate_factor () const
-{
-	return 1;
-}
-
-string
-StereoPictureAsset::cpl_node_name () const
-{
-	return "msp-cpl:MainStereoscopicPicture";
-}
-
-pair<string, string>
-StereoPictureAsset::cpl_node_attribute (bool interop) const
-{
-	if (interop) {
-		return make_pair ("xmlns:msp-cpl", "http://www.digicine.com/schemas/437-Y/2007/Main-Stereo-Picture-CPL");
-	} else {
-		return make_pair ("xmlns:msp-cpl", "http://www.smpte-ra.org/schemas/429-10/2008/Main-Stereo-Picture-CPL");
-	}
-
-	return make_pair ("", "");
-}
-
-int
-StereoPictureAsset::edit_rate_factor () const
-{
-	return 2;
-}
-
 void
 PictureAsset::write_to_cpl (xmlpp::Element* node, bool interop) const
 {
@@ -189,67 +144,20 @@ PictureAsset::equals (shared_ptr<const Asset> other, EqualityOptions opt, boost:
 	return true;
 }
 
-
-MonoPictureAsset::MonoPictureAsset (
-	boost::function<boost::filesystem::path (int)> get_path,
-	boost::filesystem::path directory,
-	string mxf_name,
-	boost::signals2::signal<void (float)>* progress,
-	int fps,
-	int intrinsic_duration,
-	Size size,
-	bool interop,
-	MXFMetadata const & metadata
-	)
-	: PictureAsset (directory, mxf_name, progress, fps, intrinsic_duration, size)
+MonoPictureAsset::MonoPictureAsset (boost::filesystem::path directory, string mxf_name)
+	: PictureAsset (directory, mxf_name)
 {
-	construct (get_path, interop, metadata);
-}
 
-MonoPictureAsset::MonoPictureAsset (
-	vector<boost::filesystem::path> const & files,
-	boost::filesystem::path directory,
-	string mxf_name,
-	boost::signals2::signal<void (float)>* progress,
-	int fps,
-	int intrinsic_duration,
-	Size size,
-	bool interop,
-	MXFMetadata const & metadata
-	)
-	: PictureAsset (directory, mxf_name, progress, fps, intrinsic_duration, size)
-{
-	construct (boost::bind (&MonoPictureAsset::path_from_list, this, _1, files), interop, metadata);
 }
 
-MonoPictureAsset::MonoPictureAsset (boost::filesystem::path directory, string mxf_name, int fps, Size size)
-	: PictureAsset (directory, mxf_name, 0, fps, 0, size)
+void
+MonoPictureAsset::create (vector<boost::filesystem::path> const & files)
 {
-
-}
-
-MonoPictureAsset::MonoPictureAsset (boost::filesystem::path directory, string mxf_name)
-	: PictureAsset (directory, mxf_name)
-{
-	ASDCP::JP2K::MXFReader reader;
-	if (ASDCP_FAILURE (reader.OpenRead (path().string().c_str()))) {
-		boost::throw_exception (MXFFileError ("could not open MXF file for reading", path().string()));
-	}
-	
-	ASDCP::JP2K::PictureDescriptor desc;
-	if (ASDCP_FAILURE (reader.FillPictureDescriptor (desc))) {
-		boost::throw_exception (DCPReadError ("could not read video MXF information"));
-	}
-
-	_size.width = desc.StoredWidth;
-	_size.height = desc.StoredHeight;
-	_edit_rate = desc.EditRate.Numerator;
-	assert (desc.EditRate.Denominator == 1);
-	_intrinsic_duration = desc.ContainerDuration;
+	create (boost::bind (&MonoPictureAsset::path_from_list, this, _1, files));
 }
 
 void
-MonoPictureAsset::construct (boost::function<boost::filesystem::path (int)> get_path, bool interop, MXFMetadata const & metadata)
+MonoPictureAsset::create (boost::function<boost::filesystem::path (int)> get_path)
 {
 	ASDCP::JP2K::CodestreamParser j2k_parser;
 	ASDCP::JP2K::FrameBuffer frame_buffer (4 * Kumu::Megabyte);
@@ -262,7 +170,7 @@ MonoPictureAsset::construct (boost::function<boost::filesystem::path (int)> get_
 	picture_desc.EditRate = ASDCP::Rational (_edit_rate, 1);
 	
 	ASDCP::WriterInfo writer_info;
-	fill_writer_info (&writer_info, _uuid, interop, metadata);
+	fill_writer_info (&writer_info, _uuid, _interop, _metadata);
 	
 	ASDCP::JP2K::MXFWriter mxf_writer;
 	if (ASDCP_FAILURE (mxf_writer.OpenWrite (path().string().c_str(), writer_info, picture_desc, 16384, false))) {
@@ -291,6 +199,26 @@ MonoPictureAsset::construct (boost::function<boost::filesystem::path (int)> get_
 	}
 }
 
+void
+MonoPictureAsset::read ()
+{
+	ASDCP::JP2K::MXFReader reader;
+	if (ASDCP_FAILURE (reader.OpenRead (path().string().c_str()))) {
+		boost::throw_exception (MXFFileError ("could not open MXF file for reading", path().string()));
+	}
+	
+	ASDCP::JP2K::PictureDescriptor desc;
+	if (ASDCP_FAILURE (reader.FillPictureDescriptor (desc))) {
+		boost::throw_exception (DCPReadError ("could not read video MXF information"));
+	}
+
+	_size.width = desc.StoredWidth;
+	_size.height = desc.StoredHeight;
+	_edit_rate = desc.EditRate.Numerator;
+	assert (desc.EditRate.Denominator == 1);
+	_intrinsic_duration = desc.ContainerDuration;
+}
+
 boost::filesystem::path
 MonoPictureAsset::path_from_list (int f, vector<boost::filesystem::path> const & files) const
 {
@@ -303,7 +231,6 @@ MonoPictureAsset::get_frame (int n) const
 	return shared_ptr<const MonoPictureFrame> (new MonoPictureFrame (path().string(), n, _decryption_context));
 }
 
-
 bool
 MonoPictureAsset::equals (shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, string)> note) const
 {
@@ -436,8 +363,14 @@ PictureAsset::frame_buffer_equals (
 }
 
 
-StereoPictureAsset::StereoPictureAsset (boost::filesystem::path directory, string mxf_name, int fps, int intrinsic_duration)
-	: PictureAsset (directory, mxf_name, 0, fps, intrinsic_duration, Size (0, 0))
+StereoPictureAsset::StereoPictureAsset (boost::filesystem::path directory, string mxf_name)
+	: PictureAsset (directory, mxf_name)
+{
+	
+}
+
+void
+StereoPictureAsset::read ()
 {
 	ASDCP::JP2K::MXFSReader reader;
 	if (ASDCP_FAILURE (reader.OpenRead (path().string().c_str()))) {
@@ -460,10 +393,10 @@ StereoPictureAsset::get_frame (int n) const
 }
 
 shared_ptr<PictureAssetWriter>
-MonoPictureAsset::start_write (bool overwrite, bool interop, MXFMetadata const & metadata)
+MonoPictureAsset::start_write (bool overwrite)
 {
 	/* XXX: can't we use shared_ptr here? */
-	return shared_ptr<MonoPictureAssetWriter> (new MonoPictureAssetWriter (this, overwrite, interop, metadata));
+	return shared_ptr<MonoPictureAssetWriter> (new MonoPictureAssetWriter (this, overwrite));
 }
 
 string
@@ -472,15 +405,45 @@ PictureAsset::key_type () const
 	return "MDIK";
 }
 
-StereoPictureAsset::StereoPictureAsset (boost::filesystem::path directory, string mxf_name, int fps, Size size)
-	: PictureAsset (directory, mxf_name, 0, fps, 0, size)
+shared_ptr<PictureAssetWriter>
+StereoPictureAsset::start_write (bool overwrite)
 {
+	return shared_ptr<StereoPictureAssetWriter> (new StereoPictureAssetWriter (this, overwrite));
+}
 
+string
+MonoPictureAsset::cpl_node_name () const
+{
+	return "MainPicture";
 }
 
-shared_ptr<PictureAssetWriter>
-StereoPictureAsset::start_write (bool overwrite, bool interop, MXFMetadata const & metadata)
+int
+MonoPictureAsset::edit_rate_factor () const
+{
+	return 1;
+}
+
+string
+StereoPictureAsset::cpl_node_name () const
 {
-	return shared_ptr<StereoPictureAssetWriter> (new StereoPictureAssetWriter (this, overwrite, interop, metadata));
+	return "msp-cpl:MainStereoscopicPicture";
+}
+
+pair<string, string>
+StereoPictureAsset::cpl_node_attribute (bool interop) const
+{
+	if (interop) {
+		return make_pair ("xmlns:msp-cpl", "http://www.digicine.com/schemas/437-Y/2007/Main-Stereo-Picture-CPL");
+	} else {
+		return make_pair ("xmlns:msp-cpl", "http://www.smpte-ra.org/schemas/429-10/2008/Main-Stereo-Picture-CPL");
+	}
+
+	return make_pair ("", "");
+}
+
+int
+StereoPictureAsset::edit_rate_factor () const
+{
+	return 2;
 }
 
diff --git a/src/picture_asset.h b/src/picture_asset.h
index 495c6647..d1b097fa 100644
--- a/src/picture_asset.h
+++ b/src/picture_asset.h
@@ -48,31 +48,15 @@ public:
 	 */
 	PictureAsset (boost::filesystem::path directory, std::string mxf_name);
 
-	/** Construct a PictureAsset.
-	 *  This class will not write anything to disk in this constructor, but subclasses may.
-	 *
-	 *  @param directory Directory where MXF file is.
-	 *  @param mxf_name Name of MXF file.
-	 *  @param progress Signal to use to inform of progres, or 0.
-	 *  @param fps Video frames per second.
-	 *  @param intrinsic_duration Total number of frames in the asset.
-	 *  @param size Size of video frame images in pixels.
-	 */
-	PictureAsset (
-		boost::filesystem::path directory,
-		std::string mxf_name,
-		boost::signals2::signal<void (float)>* progress,
-		int fps,
-		int intrinsic_duration,
-		Size
-		);
-
 	/** Start a progressive write to this asset.
 	 *  @param overwrite true to overwrite an existing MXF file; in this mode, writing can be resumed to a partially-written MXF; false if the
 	 *  MXF file does not exist.
-	 *  @param metadata MXF metadata to use.
 	 */
-	virtual boost::shared_ptr<PictureAssetWriter> start_write (bool overwrite, bool interop, MXFMetadata const & metadata = MXFMetadata ()) = 0;
+	virtual boost::shared_ptr<PictureAssetWriter> start_write (bool overwrite) = 0;
+
+	virtual void read () = 0;
+	virtual void create (std::vector<boost::filesystem::path> const &) {}
+	virtual void create (boost::function<boost::filesystem::path (int)>) {}
 	
 	bool equals (boost::shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, std::string)> note) const;
 
@@ -80,6 +64,10 @@ public:
 		return _size;
 	}
 
+	void set_size (Size s) {
+		_size = s;
+	}
+
 	void write_to_cpl (xmlpp::Element *, bool) const;
 
 protected:	
@@ -101,70 +89,14 @@ private:
 class MonoPictureAsset : public PictureAsset
 {
 public:
-	/** Construct a MonoPictureAsset, generating the MXF from the JPEG2000 files.
-	 *  This may take some time; progress is indicated by emission of the Progress signal.
-	 *
-	 *  @param files Pathnames of JPEG2000 files, in frame order.
-	 *  @param directory Directory in which to create MXF file.
-	 *  @param mxf_name Name of MXF file to create.
-	 *  @param progress Signal to inform of progress.
-	 *  @param fps Video frames per second.
-	 *  @param intrinsic_duration Total number of frames in the asset.
-	 *  @param size Size of images in pixels.
-	 */
-	MonoPictureAsset (
-		std::vector<boost::filesystem::path> const & files,
-		boost::filesystem::path directory,
-		std::string mxf_name,
-		boost::signals2::signal<void (float)>* progress,
-		int fps,
-		int intrinsic_duration,
-		Size size,
-		bool interop,
-		MXFMetadata const & metadata = MXFMetadata ()
-		);
-
-	/** Construct a MonoPictureAsset, generating the MXF from the JPEG2000 files.
-	 *  This may take some time; progress is indicated by emission of the Progress signal.
-	 *
-	 *  @param get_path Functor which returns a JPEG2000 file path for a given frame (frames counted from 0).
-	 *  @param directory Directory in which to create MXF file.
-	 *  @param mxf_name Name of MXF file to create.
-	 *  @param progress Signal to inform of progress.
-	 *  @param fps Video frames per second.
-	 *  @param intrinsic_duration Total number of frames in the asset.
-	 *  @param size Size of images in pixels.
-	 */
-	MonoPictureAsset (
-		boost::function<boost::filesystem::path (int)> get_path,
-		boost::filesystem::path directory,
-		std::string mxf_name,
-		boost::signals2::signal<void (float)>* progress,
-		int fps,
-		int intrinsic_duration,
-		Size size,
-		bool interop,
-		MXFMetadata const & metadata = MXFMetadata ()
-		);
-
-	/** Construct a MonoPictureAsset, reading the MXF from disk.
-	 *  @param directory Directory that the MXF is in.
-	 *  @param mxf_name The filename of the MXF within `directory'.
-	 */
 	MonoPictureAsset (boost::filesystem::path directory, std::string mxf_name);
 
-	/** Construct a MonoPictureAsset for progressive writing using
-	 *  start_write() and a MonoPictureAssetWriter.
-	 *
-	 *  @param directory Directory to put the MXF in.
-	 *  @param mxf_name Filename of the MXF within this directory.
-	 *  @param fps Video frames per second.
-	 *  @param size Size in pixels that the picture frames will be.
-	 */
-	MonoPictureAsset (boost::filesystem::path directory, std::string mxf_name, int fps, Size size);
+	void read ();
+	void create (std::vector<boost::filesystem::path> const & files);
+	void create (boost::function<boost::filesystem::path (int)> get_path);
 
 	/** Start a progressive write to a MonoPictureAsset */
-	boost::shared_ptr<PictureAssetWriter> start_write (bool, bool, MXFMetadata const & metadata = MXFMetadata ());
+	boost::shared_ptr<PictureAssetWriter> start_write (bool);
 
 	boost::shared_ptr<const MonoPictureFrame> get_frame (int n) const;
 	bool equals (boost::shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, std::string)> note) const;
@@ -180,20 +112,12 @@ private:
 class StereoPictureAsset : public PictureAsset
 {
 public:
-	StereoPictureAsset (boost::filesystem::path directory, std::string mxf_name, int fps, int intrinsic_duration);
-
-	/** Construct a StereoPictureAsset for progressive writing using
-	 *  start_write() and a StereoPictureAssetWriter.
-	 *
-	 *  @param directory Directory to put the MXF in.
-	 *  @param mxf_name Filename of the MXF within this directory.
-	 *  @param fps Video frames per second.
-	 *  @param size Size in pixels that the picture frames will be.
-	 */
-	StereoPictureAsset (boost::filesystem::path directory, std::string mxf_name, int fps, Size size);
+	StereoPictureAsset (boost::filesystem::path directory, std::string mxf_name);
 
+	void read ();
+	
 	/** Start a progressive write to a StereoPictureAsset */
-	boost::shared_ptr<PictureAssetWriter> start_write (bool, bool, MXFMetadata const & metadata = MXFMetadata ());
+	boost::shared_ptr<PictureAssetWriter> start_write (bool);
 
 	boost::shared_ptr<const StereoPictureFrame> get_frame (int n) const;
 	bool equals (boost::shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, std::string)> note) const;
diff --git a/src/picture_asset_writer.cc b/src/picture_asset_writer.cc
index f5767e3d..ca5a3e96 100644
--- a/src/picture_asset_writer.cc
+++ b/src/picture_asset_writer.cc
@@ -52,14 +52,12 @@ FrameInfo::write (ostream& s)
 }
 
 
-PictureAssetWriter::PictureAssetWriter (PictureAsset* asset, bool overwrite, bool interop, MXFMetadata const & metadata)
+PictureAssetWriter::PictureAssetWriter (PictureAsset* asset, bool overwrite)
 	: _asset (asset)
 	, _frames_written (0)
 	, _started (false)
 	, _finalized (false)
 	, _overwrite (overwrite)
-	, _interop (interop)
-	, _metadata (metadata)
 {
 
 }
@@ -90,15 +88,15 @@ struct StereoPictureAssetWriter::ASDCPState : public ASDCPStateBase
 /** @param a Asset to write to.  `a' must not be deleted while
  *  this writer class still exists, or bad things will happen.
  */
-MonoPictureAssetWriter::MonoPictureAssetWriter (PictureAsset* asset, bool overwrite, bool interop, MXFMetadata const & metadata)
-	: PictureAssetWriter (asset, overwrite, interop, metadata)
+MonoPictureAssetWriter::MonoPictureAssetWriter (PictureAsset* asset, bool overwrite)
+	: PictureAssetWriter (asset, overwrite)
 	, _state (new MonoPictureAssetWriter::ASDCPState)
 {
 	_state->encryption_context = asset->encryption_context ();
 }
 
-StereoPictureAssetWriter::StereoPictureAssetWriter (PictureAsset* asset, bool overwrite, bool interop, MXFMetadata const & metadata)
-	: PictureAssetWriter (asset, overwrite, interop, metadata)
+StereoPictureAssetWriter::StereoPictureAssetWriter (PictureAsset* asset, bool overwrite)
+	: PictureAssetWriter (asset, overwrite)
 	, _state (new StereoPictureAssetWriter::ASDCPState)
 	, _next_eye (EYE_LEFT)
 {
@@ -115,7 +113,7 @@ void libdcp::start (PictureAssetWriter* writer, shared_ptr<P> state, Q* asset, u
 	state->j2k_parser.FillPictureDescriptor (state->picture_descriptor);
 	state->picture_descriptor.EditRate = ASDCP::Rational (asset->edit_rate(), 1);
 	
-	asset->fill_writer_info (&state->writer_info, asset->uuid(), writer->_interop, writer->_metadata);
+	asset->fill_writer_info (&state->writer_info, asset->uuid(), writer->_asset->interop(), writer->_asset->metadata());
 	
 	if (ASDCP_FAILURE (state->mxf_writer.OpenWrite (
 				   asset->path().string().c_str(),
diff --git a/src/picture_asset_writer.h b/src/picture_asset_writer.h
index b6d2e92c..fd4f81ee 100644
--- a/src/picture_asset_writer.h
+++ b/src/picture_asset_writer.h
@@ -58,7 +58,7 @@ protected:
 	template <class P, class Q>
 	friend void start (PictureAssetWriter *, boost::shared_ptr<P>, Q *, uint8_t *, int);
 
-	PictureAssetWriter (PictureAsset *, bool, bool, MXFMetadata const &);
+	PictureAssetWriter (PictureAsset *, bool);
 
 	PictureAsset* _asset;
 	
@@ -71,8 +71,6 @@ protected:
 	/** true if finalize() has been called */
 	bool _finalized;
 	bool _overwrite;
-	bool _interop;
-	MXFMetadata _metadata;
 };
 
 /** A helper class for writing to MonoPictureAssets progressively (i.e. writing frame-by-frame,
@@ -95,7 +93,7 @@ public:
 private:
 	friend class MonoPictureAsset;
 
-	MonoPictureAssetWriter (PictureAsset *, bool, bool, MXFMetadata const &);
+	MonoPictureAssetWriter (PictureAsset *, bool);
 	void start (uint8_t *, int);
 
 	/* do this with an opaque pointer so we don't have to include
@@ -126,7 +124,7 @@ public:
 private:
 	friend class StereoPictureAsset;
 
-	StereoPictureAssetWriter (PictureAsset *, bool, bool, MXFMetadata const &);
+	StereoPictureAssetWriter (PictureAsset *, bool);
 	void start (uint8_t *, int);
 
 	/* do this with an opaque pointer so we don't have to include
diff --git a/src/sound_asset.cc b/src/sound_asset.cc
index 984d8f0f..ec82752c 100644
--- a/src/sound_asset.cc
+++ b/src/sound_asset.cc
@@ -42,48 +42,22 @@ using boost::shared_ptr;
 using boost::lexical_cast;
 using namespace libdcp;
 
-SoundAsset::SoundAsset (
-	vector<boost::filesystem::path> const & files,
-	boost::filesystem::path directory,
-	string mxf_name,
-	boost::signals2::signal<void (float)>* progress,
-	int fps,
-	int intrinsic_duration,
-	bool interop,
-	MXFMetadata const & metadata
-	)
-	: MXFAsset (directory, mxf_name, progress, fps, intrinsic_duration)
-	, _channels (files.size ())
+SoundAsset::SoundAsset (boost::filesystem::path directory, string mxf_name)
+	: MXFAsset (directory, mxf_name)
+	, _channels (0)
 	, _sampling_rate (0)
 {
-	assert (_channels);
-	
-	construct (boost::bind (&SoundAsset::path_from_channel, this, _1, files), interop, metadata);
+
 }
 
-SoundAsset::SoundAsset (
-	boost::function<boost::filesystem::path (Channel)> get_path,
-	boost::filesystem::path directory,
-	string mxf_name,
-	boost::signals2::signal<void (float)>* progress,
-	int fps,
-	int intrinsic_duration,
-	int channels,
-	bool interop,
-	MXFMetadata const & metadata
-	)
-	: MXFAsset (directory, mxf_name, progress, fps, intrinsic_duration)
-	, _channels (channels)
-	, _sampling_rate (0)
+void
+SoundAsset::create (vector<boost::filesystem::path> const & files)
 {
-	assert (_channels);
-	
-	construct (get_path, interop, metadata);
+	create (boost::bind (&SoundAsset::path_from_channel, this, _1, files));
 }
 
-SoundAsset::SoundAsset (boost::filesystem::path directory, string mxf_name)
-	: MXFAsset (directory, mxf_name)
-	, _channels (0)
+void
+SoundAsset::read ()
 {
 	ASDCP::PCM::MXFReader reader;
 	if (ASDCP_FAILURE (reader.OpenRead (path().string().c_str()))) {
@@ -102,14 +76,6 @@ SoundAsset::SoundAsset (boost::filesystem::path directory, string mxf_name)
 	_intrinsic_duration = desc.ContainerDuration;
 }
 
-SoundAsset::SoundAsset (boost::filesystem::path directory, string mxf_name, int fps, int channels, int sampling_rate)
-	: MXFAsset (directory, mxf_name, 0, fps, 0)
-	, _channels (channels)
-	, _sampling_rate (sampling_rate)
-{
-
-}
-
 boost::filesystem::path
 SoundAsset::path_from_channel (Channel channel, vector<boost::filesystem::path> const & files)
 {
@@ -119,10 +85,11 @@ SoundAsset::path_from_channel (Channel channel, vector<boost::filesystem::path>
 }
 
 void
-SoundAsset::construct (boost::function<boost::filesystem::path (Channel)> get_path, bool interop, MXFMetadata const & metadata)
+SoundAsset::create (boost::function<boost::filesystem::path (Channel)> get_path)
 {
 	ASDCP::Rational asdcp_edit_rate (_edit_rate, 1);
 
+	assert (_channels > 0);
  	ASDCP::PCM::WAVParser pcm_parser_channel[_channels];
 	if (pcm_parser_channel[0].OpenRead (get_path(LEFT).c_str(), asdcp_edit_rate)) {
 		boost::throw_exception (FileError ("could not open WAV file for reading", get_path(LEFT)));
@@ -172,7 +139,7 @@ SoundAsset::construct (boost::function<boost::filesystem::path (Channel)> get_pa
 	frame_buffer.Size (ASDCP::PCM::CalcFrameBufferSize (audio_desc));
 
 	ASDCP::WriterInfo writer_info;
-	MXFAsset::fill_writer_info (&writer_info, _uuid, interop, metadata);
+	MXFAsset::fill_writer_info (&writer_info, _uuid, _interop, _metadata);
 
 	ASDCP::PCM::MXFWriter mxf_writer;
 	if (ASDCP_FAILURE (mxf_writer.OpenWrite (path().string().c_str(), writer_info, audio_desc))) {
@@ -304,10 +271,10 @@ SoundAsset::get_frame (int n) const
 }
 
 shared_ptr<SoundAssetWriter>
-SoundAsset::start_write (bool interop, MXFMetadata const & metadata)
+SoundAsset::start_write ()
 {
 	/* XXX: can't we use a shared_ptr here? */
-	return shared_ptr<SoundAssetWriter> (new SoundAssetWriter (this, interop, metadata));
+	return shared_ptr<SoundAssetWriter> (new SoundAssetWriter (this));
 }
 
 struct SoundAssetWriter::ASDCPState
@@ -319,13 +286,12 @@ struct SoundAssetWriter::ASDCPState
 	ASDCP::AESEncContext* encryption_context;
 };
 
-SoundAssetWriter::SoundAssetWriter (SoundAsset* a, bool interop, MXFMetadata const & m)
+SoundAssetWriter::SoundAssetWriter (SoundAsset* a)
 	: _state (new SoundAssetWriter::ASDCPState)
 	, _asset (a)
 	, _finalized (false)
 	, _frames_written (0)
 	, _frame_buffer_offset (0)
-	, _metadata (m)
 {
 	_state->encryption_context = a->encryption_context ();
 	
@@ -344,7 +310,7 @@ SoundAssetWriter::SoundAssetWriter (SoundAsset* a, bool interop, MXFMetadata con
 	_state->frame_buffer.Size (ASDCP::PCM::CalcFrameBufferSize (_state->audio_desc));
 	memset (_state->frame_buffer.Data(), 0, _state->frame_buffer.Capacity());
 	
-	_asset->fill_writer_info (&_state->writer_info, _asset->uuid (), interop, _metadata);
+	_asset->fill_writer_info (&_state->writer_info, _asset->uuid (), _asset->interop(), _asset->metadata());
 	
 	if (ASDCP_FAILURE (_state->mxf_writer.OpenWrite (_asset->path().string().c_str(), _state->writer_info, _state->audio_desc))) {
 		boost::throw_exception (FileError ("could not open audio MXF for writing", _asset->path().string()));
diff --git a/src/sound_asset.h b/src/sound_asset.h
index 1d2a4755..d41b72d5 100644
--- a/src/sound_asset.h
+++ b/src/sound_asset.h
@@ -43,7 +43,7 @@ public:
 private:
 	friend class SoundAsset;
 
-	SoundAssetWriter (SoundAsset *, bool interop, MXFMetadata const &);
+	SoundAssetWriter (SoundAsset *);
 
 	/* no copy construction */
 	SoundAssetWriter (SoundAssetWriter const &);
@@ -62,76 +62,27 @@ private:
 	bool _finalized;
 	int _frames_written;
 	int _frame_buffer_offset;
-	MXFMetadata _metadata;
 };
 
 /** @brief An asset made up of WAV files */
 class SoundAsset : public MXFAsset
 {
 public:
-	/** Construct a SoundAsset, generating the MXF from some WAV files.
-	 *  This may take some time; progress is indicated by emission of the Progress signal.
-	 *  @param files Pathnames of sound files, in the order Left, Right, Centre, Lfe (sub), Left surround, Right surround.
-	 *  @param directory Directory in which to create MXF file.
-	 *  @param mxf_name Name of MXF file to create.
-	 *  @param progress Signal to inform of progress.
-	 *  @param fps Frames per second.
-	 *  @param length Length in frames.
-	 *  @param start_frame Frame in the source to start writing from.
-	 *  @param intrinsic_duration Length of the whole asset in frames.
-	 *  Note that this is different to entry_point in that the asset will contain no data before start_frame.
-	 */
-	SoundAsset (
-		std::vector<boost::filesystem::path> const & files,
-		boost::filesystem::path directory,
-		std::string mxf_name,
-		boost::signals2::signal<void (float)>* progress,
-		int fps,
-		int intrinsic_duration,
-		bool interop,
-		MXFMetadata const & metadata = MXFMetadata ()
-		);
-
-	/** Construct a SoundAsset, generating the MXF from some WAV files.
-	 *  This may take some time; progress is indicated by emission of the Progress signal.
-	 *  @param get_path Functor which returns a WAV file path for a given channel.
-	 *  @param directory Directory in which to create MXF file.
-	 *  @param mxf_name Name of MXF file to create.
-	 *  @param progress Signal to inform of progress.
-	 *  @param fps Frames per second.
-	 *  @param intrinsic_duration Length of the whole asset in frames.
-	 *  @param channels Number of audio channels.
-	 */
-	SoundAsset (
-		boost::function<boost::filesystem::path (Channel)> get_path,
-		boost::filesystem::path directory,
-		std::string mxf_name,
-		boost::signals2::signal<void (float)>* progress,
-		int fps,
-		int intrinsic_duration,
-		int channels,
-		bool interop,
-		MXFMetadata const & metadata = MXFMetadata ()
-		);
-
-	SoundAsset (
-		boost::filesystem::path directory,
-		std::string mxf_name
-		);
-
-	SoundAsset (
-		boost::filesystem::path directory,
-		std::string mxf_name,
-		int fps,
-		int channels,
-		int sampling_rate
-		);
-
-	boost::shared_ptr<SoundAssetWriter> start_write (bool, MXFMetadata const & metadata = MXFMetadata ());
+	SoundAsset (boost::filesystem::path directory, std::string mxf_name);
+
+	void read ();
+	void create (std::vector<boost::filesystem::path> const & files);
+	void create (boost::function<boost::filesystem::path (Channel)> get_path);
+
+	boost::shared_ptr<SoundAssetWriter> start_write ();
 	
 	bool equals (boost::shared_ptr<const Asset> other, EqualityOptions opt, boost::function<void (NoteType, std::string)> note) const;
 
 	boost::shared_ptr<const SoundFrame> get_frame (int n) const;
+
+	void set_channels (int c) {
+		_channels = c;
+	}
 	
 	int channels () const {
 		return _channels;
@@ -143,7 +94,7 @@ public:
 
 private:
 	std::string key_type () const;
-	void construct (boost::function<boost::filesystem::path (Channel)> get_path, bool interop, MXFMetadata const &);
+	void construct (boost::function<boost::filesystem::path (Channel)> get_path);
 	boost::filesystem::path path_from_channel (Channel channel, std::vector<boost::filesystem::path> const & files);
 	std::string cpl_node_name () const;