Implement MP3 encoding support

Implement MP3 encoding support

include/AudioFileMP3.h

@@ -0,0 +1,74 @@
+/*
+ * AudioFileMP3.h - Audio-device which encodes a wave stream into
+ *                  an MP3 file. This is used for song export.
+ *
+ * Copyright (c) 2017 to present Michael Gregorius <michael.gregorius.git/at/arcor[dot]de>
+ *
+ * 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_MP3_H
+#define AUDIO_FILE_MP3_H
+
+#include "lmmsconfig.h"
+
+#ifdef LMMS_HAVE_MP3LAME
+
+#include "AudioFileDevice.h"
+
+#include "lame/lame.h"
+
+
+class AudioFileMP3 : public AudioFileDevice
+{
+public:
+	AudioFileMP3( OutputSettings const & outputSettings,
+			const ch_cnt_t _channels,
+			bool & successful,
+			const QString & _file,
+			Mixer* mixer );
+	virtual ~AudioFileMP3();
+
+	static AudioFileDevice * getInst( const QString & outputFilename,
+					  OutputSettings const & outputSettings,
+					  const ch_cnt_t channels,
+					  Mixer* mixer,
+					  bool & successful )
+	{
+		return new AudioFileMP3( outputSettings, channels, successful,
+					 outputFilename, mixer );
+	}
+
+protected:
+	virtual void writeBuffer( const surroundSampleFrame * /* _buf*/,
+				  const fpp_t /*_frames*/,
+				  const float /*_master_gain*/ );
+
+private:
+	void flushRemainingBuffers();
+	bool initEncoder();
+	void tearDownEncoder();
+
+private:
+	lame_t m_lame;
+};
+
+#endif
+
+#endif

include/OutputSettings.h

@@ -38,6 +38,13 @@ public:
 		NumDepths
 	};
 
+	enum StereoMode
+	{
+		StereoMode_Stereo,
+		StereoMode_JointStereo,
+		StereoMode_Mono
+	};
+
 	class BitRateSettings
 	{
 	public:
@@ -60,10 +67,19 @@ public:
 public:
 	OutputSettings( sample_rate_t sampleRate,
 			BitRateSettings const & bitRateSettings,
-			BitDepth bitDepth ) :
+			BitDepth bitDepth,
+			StereoMode stereoMode ) :
 		m_sampleRate(sampleRate),
 		m_bitRateSettings(bitRateSettings),
-		m_bitDepth(bitDepth)
+		m_bitDepth(bitDepth),
+		m_stereoMode(stereoMode)
+	{
+	}
+
+	OutputSettings( sample_rate_t sampleRate,
+			BitRateSettings const & bitRateSettings,
+			BitDepth bitDepth ) :
+		OutputSettings(sampleRate, bitRateSettings, bitDepth, StereoMode_Stereo )
 	{
 	}
 
@@ -76,10 +92,14 @@ public:
 	BitDepth getBitDepth() const { return m_bitDepth; }
 	void setBitDepth(BitDepth bitDepth) { m_bitDepth = bitDepth; }
 
+	StereoMode getStereoMode() const { return m_stereoMode; }
+	void setStereoMode(StereoMode stereoMode) { m_stereoMode = stereoMode; }
+
 private:
 	sample_rate_t m_sampleRate;
 	BitRateSettings m_bitRateSettings;
 	BitDepth m_bitDepth;
+	StereoMode m_stereoMode;
 };
 
 #endif

include/ProjectRenderer.h

@@ -39,11 +39,14 @@ public:
 	{
 		WaveFile,
 		OggFile,
+		MP3File,
 		NumFileFormats
 	} ;
 
 	struct FileEncodeDevice
 	{
+		bool isAvailable() const { return m_getDevInst != nullptr; }
+
 		ExportFileFormats m_fileFormat;
 		const char * m_description;
 		const char * m_extension;