boost::shared_ptr<dcp::PictureAssetWriter> _picture_asset_writer;
boost::shared_ptr<dcp::SoundAsset> _sound_asset;
boost::shared_ptr<dcp::SoundAssetWriter> _sound_asset_writer;
boost::shared_ptr<dcp::PictureAssetWriter> _picture_asset_writer;
boost::shared_ptr<dcp::SoundAsset> _sound_asset;
boost::shared_ptr<dcp::SoundAssetWriter> _sound_asset_writer;