Added volume control for QAudioOutput & QAudioInput (alsa)

QTBUG-25454

- Added update to docs on volume control.
- Added internal volume adjustment for alsa implementation.
- Enabled float sample option in QAudioDeviceInfo (alsa).

Change-Id: I6b89fc8beb457d71be9ad71b538c86a008570f07
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>
Reviewed-by: Kurt Korbatits  <kurt.korbatits@nokia.com>

src/multimedia/audio/audio.pri

@@ -19,6 +19,7 @@ PRIVATE_HEADERS += \
            audio/qaudiodevicefactory_p.h \
            audio/qwavedecoder_p.h \
            audio/qsamplecache_p.h \
+           audio/qaudiohelpers_p.h
 
 SOURCES += \
            audio/qaudio.cpp \
@@ -35,7 +36,8 @@ SOURCES += \
            audio/qsound.cpp \
            audio/qaudiobuffer.cpp \
            audio/qaudioprobe.cpp \
-           audio/qaudiodecoder.cpp
+           audio/qaudiodecoder.cpp \
+           audio/qaudiohelpers.cpp
 
 mac {
     PRIVATE_HEADERS +=  audio/qaudioinput_mac_p.h \

src/multimedia/audio/qaudiodeviceinfo_alsa_p.cpp

@@ -286,6 +286,11 @@ bool QAudioDeviceInfoInternal::testSettings(const QAudioFormat& format) const
                     err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_U32_LE);
                 else if(format.byteOrder() == QAudioFormat::BigEndian)
                     err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_U32_BE);
+            } else if (format.sampleType() == QAudioFormat::Float) {
+                if (format.byteOrder() == QAudioFormat::LittleEndian)
+                    err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_FLOAT_LE);
+                else if (format.byteOrder() == QAudioFormat::BigEndian)
+                    err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_FLOAT_BE);
             }
     }
 
@@ -344,6 +349,11 @@ bool QAudioDeviceInfoInternal::testSettings(const QAudioFormat& format) const
                         err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_U32_LE);
                     else if(format.byteOrder() == QAudioFormat::BigEndian)
                         err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_U32_BE);
+                } else if (format.sampleType() == QAudioFormat::Float) {
+                    if (format.byteOrder() == QAudioFormat::LittleEndian)
+                        err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_FLOAT_LE);
+                    else if (format.byteOrder() == QAudioFormat::BigEndian)
+                        err = snd_pcm_hw_params_set_format(handle,params,SND_PCM_FORMAT_FLOAT_BE);
                 }
         }
         if(err>=0) {

src/multimedia/audio/qaudiohelpers.cpp

@@ -0,0 +1,117 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qaudiohelpers_p.h"
+
+#include <QDebug>
+
+QT_BEGIN_NAMESPACE
+
+namespace QAudioHelperInternal
+{
+
+template<class T> void adjustSamples(qreal factor, const void *src, void *dst, int samples)
+{
+    const T *pSrc = (const T *)src;
+    T *pDst = (T*)dst;
+    for ( int i = 0; i < samples; i++ )
+        pDst[i] = pSrc[i] * factor;
+}
+
+// Unsigned samples are biased around 0x80/0x8000 :/
+// This makes a pure template solution a bit unwieldy but possible
+template<class T> struct signedVersion {};
+template<> struct signedVersion<quint8>
+{
+    typedef qint8 TS;
+    enum {offset = 0x80};
+};
+
+template<> struct signedVersion<quint16>
+{
+    typedef qint16 TS;
+    enum {offset = 0x8000};
+};
+
+template<> struct signedVersion<quint32>
+{
+    typedef qint32 TS;
+    enum {offset = 0x80000000};
+};
+
+template<class T> void adjustUnsignedSamples(qreal factor, const void *src, void *dst, int samples)
+{
+    const T *pSrc = (const T *)src;
+    T *pDst = (T*)dst;
+    for ( int i = 0; i < samples; i++ ) {
+        pDst[i] = signedVersion<T>::offset + ((typename signedVersion<T>::TS)(pSrc[i] - signedVersion<T>::offset) * factor);
+    }
+}
+
+void qMultiplySamples(qreal factor, const QAudioFormat &format, const void* src, void* dest, int len)
+{
+    int samplesCount = len / (format.sampleSize()/8);
+
+    switch ( format.sampleSize() ) {
+    case 8:
+        if (format.sampleType() == QAudioFormat::SignedInt)
+            QAudioHelperInternal::adjustSamples<qint8>(factor,src,dest,samplesCount);
+        else if (format.sampleType() == QAudioFormat::UnSignedInt)
+            QAudioHelperInternal::adjustUnsignedSamples<quint8>(factor,src,dest,samplesCount);
+        break;
+    case 16:
+        if (format.sampleType() == QAudioFormat::SignedInt)
+            QAudioHelperInternal::adjustSamples<qint16>(factor,src,dest,samplesCount);
+        else if (format.sampleType() == QAudioFormat::UnSignedInt)
+            QAudioHelperInternal::adjustUnsignedSamples<quint16>(factor,src,dest,samplesCount);
+        break;
+    default:
+        if (format.sampleType() == QAudioFormat::SignedInt)
+            QAudioHelperInternal::adjustSamples<qint32>(factor,src,dest,samplesCount);
+        else if (format.sampleType() == QAudioFormat::UnSignedInt)
+            QAudioHelperInternal::adjustUnsignedSamples<quint32>(factor,src,dest,samplesCount);
+        else if (format.sampleType() == QAudioFormat::Float)
+            QAudioHelperInternal::adjustSamples<float>(factor,src,dest,samplesCount);
+    }
+}
+}
+
+QT_END_NAMESPACE

src/multimedia/audio/qaudiohelpers_p.h

@@ -0,0 +1,67 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this
+** file. Please review the following information to ensure the GNU Lesser
+** General Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QAUDIOHELPERS_H
+#define QAUDIOHELPERS_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <qaudioformat.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace QAudioHelperInternal
+{
+void qMultiplySamples(qreal factor, const QAudioFormat& format, const void *src, void* dest, int len);
+}
+
+QT_END_NAMESPACE
+
+#endif

src/multimedia/audio/qaudioinput.cpp

@@ -279,7 +279,7 @@ int QAudioInput::bufferSize() const
 /*!
     Returns the amount of audio data available to read in bytes.
 
-    NOTE: returned value is only valid while in QAudio::ActiveState or QAudio::IdleState
+    Note: returned value is only valid while in QAudio::ActiveState or QAudio::IdleState
     state, otherwise returns zero.
 */
 
@@ -332,6 +332,8 @@ int QAudioInput::notifyInterval() const
     If the device does not support adjusting the input
     volume then \a volume will be ignored and the input
     volume will remain at 1.0.
+
+    Note: Adjustments to the volume will change the volume of this audio stream, not the global volume.
 */
 void QAudioInput::setVolume(qreal volume)
 {

src/multimedia/audio/qaudioinput_alsa_p.cpp

@@ -53,6 +53,7 @@
 #include <QtCore/qcoreapplication.h>
 #include "qaudioinput_alsa_p.h"
 #include "qaudiodeviceinfo_alsa_p.h"
+#include "qaudiohelpers_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -77,6 +78,8 @@ QAudioInputPrivate::QAudioInputPrivate(const QByteArray &device)
     pullMode = true;
     resuming = false;
 
+    m_volume = 1.0f;
+
     m_device = device;
 
     timer = new QTimer(this);
@@ -91,6 +94,16 @@ QAudioInputPrivate::~QAudioInputPrivate()
     delete timer;
 }
 
+void QAudioInputPrivate::setVolume(qreal vol)
+{
+    m_volume = vol;
+}
+
+qreal QAudioInputPrivate::volume() const
+{
+    return m_volume;
+}
+
 QAudio::Error QAudioInputPrivate::error() const
 {
     return errorState;
@@ -537,9 +550,11 @@ qint64 QAudioInputPrivate::read(char* data, qint64 len)
                 frames = buffer_frames;
 
             int readFrames = snd_pcm_readi(handle, buffer, frames);
+            bytesRead = snd_pcm_frames_to_bytes(handle, readFrames);
+            if (m_volume < 1.0f)
+                QAudioHelperInternal::qMultiplySamples(m_volume, settings, buffer, buffer, bytesRead);
 
             if (readFrames >= 0) {
-                bytesRead = snd_pcm_frames_to_bytes(handle, readFrames);
                 ringBuffer.write(buffer, bytesRead);
 #ifdef DEBUG_AUDIO
                 qDebug() << QString::fromLatin1("read in bytes = %1 (frames=%2)").arg(bytesRead).arg(readFrames).toLatin1().constData();

src/multimedia/audio/qaudioinput_alsa_p.h

@@ -126,6 +126,8 @@ public:
     QAudio::State state() const;
     void setFormat(const QAudioFormat& fmt);
     QAudioFormat format() const;
+    void setVolume(qreal);
+    qreal volume() const;
     bool resuming;
     snd_pcm_t* handle;
     qint64 totalTimeValue;
@@ -166,6 +168,7 @@ private:
     snd_pcm_format_t pcmformat;
     snd_timestamp_t* timestamp;
     snd_pcm_hw_params_t *hwparams;
+    qreal m_volume;
 };
 
 class InputPrivate : public QIODevice

src/multimedia/audio/qaudiooutput.cpp

@@ -349,6 +349,7 @@ QAudio::State QAudioOutput::state() const
 /*!
     Sets the volume.
     Where \a volume is between 0.0 and 1.0 inclusive.
+    Note: Adjustments to the volume will change the volume of this audio stream, not the global volume.
 */
 void QAudioOutput::setVolume(qreal volume)
 {

src/multimedia/audio/qaudiooutput_alsa_p.cpp

@@ -53,6 +53,7 @@
 #include <QtCore/qcoreapplication.h>
 #include "qaudiooutput_alsa_p.h"
 #include "qaudiodeviceinfo_alsa_p.h"
+#include "qaudiohelpers_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -81,6 +82,8 @@ QAudioOutputPrivate::QAudioOutputPrivate(const QByteArray &device)
     resuming = false;
     opened = false;
 
+    m_volume = 1.0f;
+
     m_device = device;
 
     timer = new QTimer(this);
@@ -95,6 +98,16 @@ QAudioOutputPrivate::~QAudioOutputPrivate()
     delete timer;
 }
 
+void QAudioOutputPrivate::setVolume(qreal vol)
+{
+    m_volume = vol;
+}
+
+qreal QAudioOutputPrivate::volume() const
+{
+    return m_volume;
+}
+
 QAudio::Error QAudioOutputPrivate::error() const
 {
     return errorState;
@@ -571,15 +584,23 @@ qint64 QAudioOutputPrivate::write( const char *data, qint64 len )
 #endif
     int frames, err;
     int space = bytesFree();
-    if(len < space) {
+
-        // Just write it
+    if (!space)
-        frames = snd_pcm_bytes_to_frames( handle, (int)len );
+        return 0;
-        err = snd_pcm_writei( handle, data, frames );
+
+    if (len < space)
+        space = len;
+
+    frames = snd_pcm_bytes_to_frames(handle, space);
+
+    if (m_volume < 1.0f) {
+        char out[space];
+        QAudioHelperInternal::qMultiplySamples(m_volume, settings, data, out, space);
+        err = snd_pcm_writei(handle, out, frames);
     } else {
-        // Only write space worth
-        frames = snd_pcm_bytes_to_frames( handle, (int)space );
         err = snd_pcm_writei(handle, data, frames);
     }
+
     if(err > 0) {
         totalTimeValue += err;
         resuming = false;

src/multimedia/audio/qaudiooutput_alsa_p.h

@@ -103,6 +103,9 @@ public:
     QAudio::State state() const;
     void setFormat(const QAudioFormat& fmt);
     QAudioFormat format() const;
+    void setVolume(qreal);
+    qreal volume() const;
+
 
     QIODevice* audioSource;
     QAudioFormat settings;
@@ -150,6 +153,7 @@ private:
     snd_pcm_format_t pcmformat;
     snd_timestamp_t* timestamp;
     snd_pcm_hw_params_t *hwparams;
+    qreal m_volume;
 };
 
 class OutputPrivate : public QIODevice