prepare for dither implementation

git-svn-id: http://svn.code.sf.net/p/qmmp-dev/code/trunk/qmmp@5985 90c681e8-e032-0410-971d-27865f9a5e38

5 files changed, 173 insertions, 4 deletions

diff --git a/src/qmmp/dithering.cpp b/src/qmmp/dithering.cpp
new file mode 100644
index 000000000..dd5513b47
--- /dev/null
+++ b/src/qmmp/dithering.cpp
@@ -0,0 +1,108 @@
+/***************************************************************************
+ *  Based on madplay project                                               *
+ *                                                                         *
+ * Copyright (C) 2000-2004 Robert Leslie <rob@mars.org>                    *
+ * Copyright (C) 2015 Ilya Kotov forkotov02@hotmail.ru                     *
+ *                                                                         *
+ *   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; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.         *
+ ***************************************************************************/
+
+#include "dithering_p.h"
+
+Dithering::Dithering() : Effect()
+{
+    qDebug("=========================");
+
+    float output, random;
+
+    for(int i = 0; i < 9; ++i)
+    {
+        m_dither[i].error[0] = 0.0f;
+        m_dither[i].error[1] = 0.0f;
+        m_dither[i].error[2] = 0.0f;
+        m_dither[i].random = 0.0f;
+    }
+
+    //for(int i = 0; i < 500; ++i)
+    //    audioLinearDither(0, &m_dither[0]);
+
+    qDebug("=%x=", 1<< 8);
+}
+
+void Dithering::configure(quint32 srate, ChannelMap map)
+{
+    m_chan = map.count();
+    for(int i = 0; i < 9; ++i)
+    {
+        m_dither[i].error[0] = 0.0f;
+        m_dither[i].error[1] = 0.0f;
+        m_dither[i].error[2] = 0.0f;
+        m_dither[i].random = 0.0f;
+    }
+    Effect::configure(srate, map);
+}
+
+void Dithering::applyEffect(Buffer *b)
+{
+    for(size_t i = 0; i < b->samples; ++i)
+    {
+        b->data[i] = audioLinearDither(b->data[i], &m_dither[i % m_chan]);
+    }
+}
+
+quint32 Dithering::prng(quint32 state) // 32-bit pseudo-random number generator
+{
+    return (state * 0x0019660dL + 0x3c6ef35fL) & 0xffffffffL;
+}
+
+float Dithering::audioLinearDither(float sample, AudioDither *dither)
+{
+    float output; quint32 random;
+
+    /* noise shape */
+    sample += dither->error[0] - dither->error[1] + dither->error[2];
+
+    dither->error[2] = dither->error[1];
+    dither->error[1] = dither->error[0] / 2;
+
+    output = sample;
+
+    /* dither */
+    random = prng(dither->random);
+    output += ((float) (random & 0x0000ffffL) - (dither->random & 0x0000ffffL)) / 0xffffffffL;
+    dither->random = random;
+
+    /* clip */
+    if (output > 1.0f)
+    {
+        output = 1.0f;
+
+        if (sample > 1.0f)
+            sample = 1.0f;
+    }
+    else if (output < 1.0f)
+    {
+        output = 1.0f;
+
+        if (sample < 1.0f)
+            sample = 1.0f;
+    }
+
+    /* error feedback */
+    dither->error[0] = sample - output;
+
+    return output;
+}
diff --git a/src/qmmp/dithering_p.h b/src/qmmp/dithering_p.h
new file mode 100644
index 000000000..db25c00d2
--- /dev/null
+++ b/src/qmmp/dithering_p.h
@@ -0,0 +1,56 @@
+/***************************************************************************
+ *  Based on madplay project                                               *
+ *                                                                         *
+ * Copyright (C) 2000-2004 Robert Leslie <rob@mars.org>                    *
+ * Copyright (C) 2015 Ilya Kotov forkotov02@hotmail.ru                     *
+ *                                                                         *
+ *   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; if not, write to the                         *
+ *   Free Software Foundation, Inc.,                                       *
+ *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.         *
+ ***************************************************************************/
+
+
+#ifndef DITHERING_P_H
+#define DITHERING_P_H
+
+#include "effect.h"
+
+/** @internal
+    @author Ilya Kotov <forkotov02@hotmail.ru>
+*/
+class Dithering : public Effect
+{
+public:
+    Dithering();
+
+    void configure(quint32 srate, ChannelMap map);
+    void applyEffect(Buffer *b);
+
+private:
+    int m_chan;
+
+    typedef struct
+    {
+        float error[3];
+        quint32 random;
+
+    } AudioDither;
+
+    AudioDither m_dither[9];
+
+    quint32 prng(quint32 state);
+    float audioLinearDither(float sample, AudioDither *dither);
+};
+
+#endif // DITHERING_P_H
diff --git a/src/qmmp/qmmp.pro b/src/qmmp/qmmp.pro
index 3351a1096..0bf127f95 100644
--- a/src/qmmp/qmmp.pro
+++ b/src/qmmp/qmmp.pro
@@ -39,7 +39,8 @@ HEADERS += \
     qmmpplugincache_p.h \
     channelmap.h \
     channelconverter_p.h \
-    audioconverter.h
+    audioconverter.h \
+    dithering_p.h
 SOURCES += recycler.cpp \
     decoder.cpp \
     output.cpp \
@@ -71,7 +72,8 @@ SOURCES += recycler.cpp \
     qmmpplugincache.cpp \
     channelmap.cpp \
     channelconverter.cpp \
-    volume.cpp
+    volume.cpp \
+    dithering.cpp
 FORMS +=
 unix:TARGET = ../../lib/qmmp
 win32:TARGET = ../../../bin/qmmp
diff --git a/src/qmmp/qmmpaudioengine.cpp b/src/qmmp/qmmpaudioengine.cpp
index dd8e57c25..b736db2e8 100644
--- a/src/qmmp/qmmpaudioengine.cpp
+++ b/src/qmmp/qmmpaudioengine.cpp
@@ -1,5 +1,5 @@
 /***************************************************************************
- *   Copyright (C) 2009-2015 by Ilya Kotov                                 *
+ *   Copyright (C) 2009-2016 by Ilya Kotov                                 *
  *   forkotov02@hotmail.ru                                                 *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
@@ -33,6 +33,7 @@
 #include "audioconverter.h"
 #include "qmmpaudioengine_p.h"
 #include "channelconverter_p.h"
+#include "dithering_p.h"
 #include "metadatamanager.h"
 
 #define TRANSPORT_TIMEOUT 5000 //ms
@@ -54,6 +55,8 @@ QmmpAudioEngine::QmmpAudioEngine(QObject *parent)
     connect(m_settings, SIGNAL(eqSettingsChanged()), SLOT(updateEqSettings()));
     reset();
     m_instance = this;
+
+    Dithering d;
 }
 
 QmmpAudioEngine::~QmmpAudioEngine()
diff --git a/src/qmmp/qmmpaudioengine_p.h b/src/qmmp/qmmpaudioengine_p.h
index 14446e802..92c39fc6e 100644
--- a/src/qmmp/qmmpaudioengine_p.h
+++ b/src/qmmp/qmmpaudioengine_p.h
@@ -1,5 +1,5 @@
 /***************************************************************************
- *   Copyright (C) 2009-2013 by Ilya Kotov                                 *
+ *   Copyright (C) 2009-2016 by Ilya Kotov                                 *
  *   forkotov02@hotmail.ru                                                 *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *