Add FLAC export and related options (#3731)

* Add FLAC export, based on WAV renderer

* Depend on sndfile>=1.0.18 (previously >=1.0.11)

* Add compression option to FLAC export, if available.

The code related to compression is only generated if LMMS_HAVE_SF_COMPLEVEL is defined(libsndfile>=1.0.26).

* Save into the correct file extension upon single-export.

* Use unique_ptr in FLAC renderer and be more expressive about involved types.

* Use unique_ptr and remove manual memory management in ExportProjectDialog

* Add 'flac' format info to --help and manpage

include/AudioFileFlac.h

@@ -0,0 +1,74 @@
+/*
+ * AudioFileFlac.h - Audio device which encodes a wave stream into a FLAC file.
+ *
+ * Copyright (c) 2017 to present Levin Oehlmann <irrenhaus3/at/gmail[dot]com> et al.
+ *
+ * This file is part of LMMS - https://lmms.io
+ *
+ * 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 (see COPYING); if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ *
+ */
+
+#ifndef AUDIO_FILE_FLAC_H
+#define AUDIO_FILE_FLAC_H
+
+#include "lmmsconfig.h"
+
+#include "AudioFileDevice.h"
+#include <sndfile.h>
+
+class AudioFileFlac: public AudioFileDevice
+{
+public:
+	AudioFileFlac(OutputSettings const& outputSettings,
+			ch_cnt_t const channels,
+			bool& successful,
+			QString const& file,
+			Mixer* mixer
+	);
+
+	virtual ~AudioFileFlac();
+
+	static AudioFileDevice* getInst(QString const& outputFilename,
+			OutputSettings const& outputSettings,
+			ch_cnt_t const channels,
+			Mixer* mixer,
+			bool& successful)
+	{
+		return new AudioFileFlac(
+			outputSettings,
+			channels,
+			successful,
+			outputFilename,
+			mixer
+		);
+	}
+
+private:
+
+	SF_INFO  m_sfinfo;
+	SNDFILE* m_sf;
+
+	virtual void writeBuffer(surroundSampleFrame const* _ab,
+						fpp_t const frames,
+						float master_gain) override;
+
+	bool startEncoding();
+	void finishEncoding();
+
+};
+
+#endif //AUDIO_FILE_FLAC_H

include/ExportProjectDialog.h

@@ -28,7 +28,7 @@
 #define EXPORT_PROJECT_DIALOG_H
 
 #include <QDialog>
-#include <vector>
+#include <memory>
 #include "ui_export_project.h"
 
 #include "ProjectRenderer.h"
@@ -39,8 +39,6 @@ class ExportProjectDialog : public QDialog, public Ui::ExportProjectDialog
 	Q_OBJECT
 public:
 	ExportProjectDialog( const QString & _file_name, QWidget * _parent, bool multi_export );
-	virtual ~ExportProjectDialog();
-
 
 protected:
 	virtual void reject( void );
@@ -62,7 +60,7 @@ private:
 	bool m_multiExport;
 
 	ProjectRenderer::ExportFileFormats m_ft;
-	RenderManager* m_renderManager;
+	std::unique_ptr<RenderManager> m_renderManager;
 } ;
 
 #endif

include/OutputSettings.h

@@ -72,7 +72,8 @@ public:
 		m_sampleRate(sampleRate),
 		m_bitRateSettings(bitRateSettings),
 		m_bitDepth(bitDepth),
-		m_stereoMode(stereoMode)
+		m_stereoMode(stereoMode),
+		m_compressionLevel(0.5)
 	{
 	}
 
@@ -95,11 +96,19 @@ public:
 	StereoMode getStereoMode() const { return m_stereoMode; }
 	void setStereoMode(StereoMode stereoMode) { m_stereoMode = stereoMode; }
 
+
+	double getCompressionLevel() const{ return m_compressionLevel; }
+	void setCompressionLevel(double level){
+		// legal range is 0.0 to 1.0.
+		m_compressionLevel = level;
+	}
+
 private:
 	sample_rate_t m_sampleRate;
 	BitRateSettings m_bitRateSettings;
 	BitDepth m_bitDepth;
 	StereoMode m_stereoMode;
+	double m_compressionLevel;
 };
 
 #endif

include/ProjectRenderer.h

@@ -38,6 +38,7 @@ public:
 	enum ExportFileFormats: int
 	{
 		WaveFile,
+		FlacFile,
 		OggFile,
 		MP3File,
 		NumFileFormats