Details
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Bug
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Resolution: Done
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P2: Important
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5.3.2
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None
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Desktop (Ubuntu 14.04. 64-bit, GCC 4.8.2)
Android (Samsung Galaxy Tab2 10.1)
Android NDK r10
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Android
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9496d5fba5439bf4e4c1d80b5e5f76af82b89165
Description
I am not able to adjust the audio input volume on Android. Please find attached a minimal code example producing the following output:
Desktop (Ubuntu 14.04. 64-bit) volume set: 0 volume returned: 0 bytes read: 31008 min value: -2599 max value: 25615 volume set: 0.1 volume returned: 0.1 bytes read: 20672 min value: 0 max value: 0 volume set: 0.2 volume returned: 0.2 bytes read: 20672 min value: -15485 max value: 7761 volume set: 0.3 volume returned: 0.3 bytes read: 16646 min value: -12864 max value: 11128 volume set: 0.4 volume returned: 0.4 bytes read: 28778 min value: -16597 max value: 23752 volume set: 0.5 volume returned: 0.5 bytes read: 20672 min value: -18153 max value: 32530 volume set: 0.6 volume returned: 0.6 bytes read: 20672 min value: -15869 max value: 32767 volume set: 0.7 volume returned: 0.7 bytes read: 15856 min value: -11264 max value: 30963 volume set: 0.8 volume returned: 0.8 bytes read: 29174 min value: -10181 max value: 32767 volume set: 0.9 volume returned: 0.9 bytes read: 20672 min value: -7711 max value: 32767 volume set: 1 volume returned: 1 bytes read: 20672 min value: -6484 max value: 32767 Android (Samsung Galaxy Tab2 10.1) D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0 volume returned: 0 bytes read: 32768 min value: -25488 max value: 27945 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.1 volume returned: 0.1 bytes read: 32768 min value: -26728 max value: 31593 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.2 volume returned: 0.2 bytes read: 32768 min value: -28400 max value: 27121 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.3 volume returned: 0.3 bytes read: 32768 min value: -27679 max value: 26496 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.4 volume returned: 0.4 bytes read: 32768 min value: -29840 max value: 30029 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.5 volume returned: 0.5 bytes read: 32768 min value: -26258 max value: 27485 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.6 volume returned: 0.6 bytes read: 32768 min value: -27754 max value: 29813 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.7 volume returned: 0.7 bytes read: 32768 min value: -26040 max value: 29565 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.8 volume returned: 0.8 bytes read: 32768 min value: -28947 max value: 29668 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 0.9 volume returned: 0.9 bytes read: 32768 min value: -29395 max value: 32061 D/Qt ( 4385): ../MinimalQAudioInExample/myobject.cpp:66 (void MyObject::processAudio()): volume set: 1 volume returned: 1 bytes read: 32768 min value: -28067 max value: 26618 I/AndroidRuntime( 4385): VM exiting with result code 0, cleanup skipped.
observations:
desktop: volume 0.0, values != 0;
volume 0.1, values == 0;
values are increasing along with volume like expected;
android: volume setting is accepted, but has no real effect;
volume 0.0, values != 0;
this contradicts the documentation, where not supported volume setting always returns 1.0;
myobject.h
#ifndef MYOBJECT_H #define MYOBJECT_H #include <QObject> #include <QAudioFormat> #include <QAudioInput> #include <QIODevice> class MyObject : public QObject { Q_OBJECT public: explicit MyObject(QObject *parent = 0); ~MyObject(void); int init(void); public slots: void processAudio(void); private: qreal _volume; QAudioFormat *_ptrAudioFormat; QAudioInput *_ptrAudioInput; QIODevice *_ptrInputDevice; int _bufferSize; }; #endif // MYOBJECT_H
myobject.cpp
MyObject::MyObject(QObject *parent) :
QObject(parent),
_volume(0.0),
_ptrAudioFormat(0),
_ptrAudioInput(0),
_ptrInputDevice(0),
_bufferSize(32 * 1024)
{
}
int MyObject::init()
{
_ptrAudioFormat = new QAudioFormat();
_ptrAudioFormat->setChannelCount(1);
_ptrAudioFormat->setSampleRate(16000);
_ptrAudioFormat->setSampleSize(16);
_ptrAudioFormat->setSampleType(QAudioFormat::SignedInt);
_ptrAudioFormat->setByteOrder(QAudioFormat::LittleEndian);
_ptrAudioFormat->setCodec("audio/pcm");
_ptrAudioInput = new QAudioInput(*_ptrAudioFormat);
_ptrAudioInput->setBufferSize(_bufferSize);
_ptrAudioInput->setVolume(_volume);
_ptrInputDevice = _ptrAudioInput->start();
if (_ptrInputDevice == 0)
{
qDebug() << _ptrAudioInput->error();
return -1;
}
else
{
connect(_ptrInputDevice, SIGNAL(readyRead()), this, SLOT(processAudio()));
}
return 0;
}
MyObject::~MyObject()
{
_ptrInputDevice = 0;
if (_ptrAudioInput)
{
_ptrAudioInput->stop();
delete _ptrAudioInput; _ptrAudioInput = 0;
}
if (_ptrAudioFormat)
{
delete _ptrAudioFormat; _ptrAudioFormat = 0;
}
}
void MyObject::processAudio()
{
char *byteBuffer = new char[_bufferSize];
short *sampleBuffer = new short[_bufferSize / sizeof(short)];
_ptrAudioInput->setVolume(_volume);
int bytesRead = static_cast<int>(_ptrInputDevice->read(byteBuffer, _bufferSize));
memcpy(sampleBuffer, byteBuffer, bytesRead);
int samplesRead = bytesRead / sizeof(short);
int maxValue = 0; int minValue = 0;
for (int s = 0; s < samplesRead; s ++)
{
int value = static_cast<int>(sampleBuffer[s]);
if (minValue > value) { minValue = value; }
if (maxValue < value) { maxValue = value; }
}
qDebug() << "volume set: " << _volume
<< " volume returned: " << _ptrAudioInput->volume()
<< " bytes read: " << bytesRead
<< " min value: " << minValue
<< " max value: " << maxValue;
delete [] sampleBuffer; sampleBuffer = 0;
delete [] byteBuffer; byteBuffer = 0;
if (_volume > 0.9)
{
QApplication::exit(0);
}
else
{
_volume += 0.1;
}
}
main.cpp
int main(int argc, char *argv[]) { QApplication app(argc, argv); MyObject obj; int initValue = obj.init(); if (initValue != 0) { return initValue; } return app.exec(); }