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Diffstat (limited to 'src/multimedia/audio/qaudiooutput.cpp')
| -rw-r--r-- | src/multimedia/audio/qaudiooutput.cpp | 430 |
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diff --git a/src/multimedia/audio/qaudiooutput.cpp b/src/multimedia/audio/qaudiooutput.cpp new file mode 100644 index 000000000..95a28a2bf --- /dev/null +++ b/src/multimedia/audio/qaudiooutput.cpp @@ -0,0 +1,430 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtMultimedia module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, 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. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + + +#include <QtMultimedia/qaudio.h> +#include <QtMultimedia/qaudiodeviceinfo.h> +#include <QtMultimedia/qaudioengine.h> +#include <QtMultimedia/qaudiooutput.h> + +#include "qaudiodevicefactory_p.h" + + +QT_BEGIN_NAMESPACE + +/*! + \class QAudioOutput + \brief The QAudioOutput class provides an interface for sending audio data to an audio output device. + + \inmodule QtMultimedia + \ingroup multimedia + \since 4.6 + + You can construct an audio output with the system's + \l{QAudioDeviceInfo::defaultOutputDevice()}{default audio output + device}. It is also possible to create QAudioOutput with a + specific QAudioDeviceInfo. When you create the audio output, you + should also send in the QAudioFormat to be used for the playback + (see the QAudioFormat class description for details). + + To play a file: + + Starting to play an audio stream is simply a matter of calling + start() with a QIODevice. QAudioOutput will then fetch the data it + needs from the io device. So playing back an audio file is as + simple as: + + \code + QFile inputFile; // class member. + QAudioOutput* audio; // class member. + \endcode + + \code + inputFile.setFileName("/tmp/test.raw"); + inputFile.open(QIODevice::ReadOnly); + + QAudioFormat format; + // Set up the format, eg. + format.setFrequency(8000); + format.setChannels(1); + format.setSampleSize(8); + format.setCodec("audio/pcm"); + format.setByteOrder(QAudioFormat::LittleEndian); + format.setSampleType(QAudioFormat::UnSignedInt); + + QAudioDeviceInfo info(QAudioDeviceInfo::defaultOutputDevice()); + if (!info.isFormatSupported(format)) { + qWarning()<<"raw audio format not supported by backend, cannot play audio."; + return; + } + + audio = new QAudioOutput(format, this); + connect(audio,SIGNAL(stateChanged(QAudio::State)),SLOT(finishedPlaying(QAudio::State))); + audio->start(&inputFile); + + \endcode + + The file will start playing assuming that the audio system and + output device support it. If you run out of luck, check what's + up with the error() function. + + After the file has finished playing, we need to stop the device: + + \code + void finishedPlaying(QAudio::State state) + { + if(state == QAudio::IdleState) { + audio->stop(); + inputFile.close(); + delete audio; + } + } + \endcode + + At any given time, the QAudioOutput will be in one of four states: + active, suspended, stopped, or idle. These states are described + by the QAudio::State enum. + State changes are reported through the stateChanged() signal. You + can use this signal to, for instance, update the GUI of the + application; the mundane example here being changing the state of + a \c { play/pause } button. You request a state change directly + with suspend(), stop(), reset(), resume(), and start(). + + While the stream is playing, you can set a notify interval in + milliseconds with setNotifyInterval(). This interval specifies the + time between two emissions of the notify() signal. This is + relative to the position in the stream, i.e., if the QAudioOutput + is in the SuspendedState or the IdleState, the notify() signal is + not emitted. A typical use-case would be to update a + \l{QSlider}{slider} that allows seeking in the stream. + If you want the time since playback started regardless of which + states the audio output has been in, elapsedUSecs() is the function for you. + + If an error occurs, you can fetch the \l{QAudio::Error}{error + type} with the error() function. Please see the QAudio::Error enum + for a description of the possible errors that are reported. When + an error is encountered, the state changes to QAudio::StoppedState. + You can check for errors by connecting to the stateChanged() + signal: + + \snippet doc/src/snippets/audio/main.cpp 3 + + \sa QAudioInput, QAudioDeviceInfo +*/ + +/*! + Construct a new audio output and attach it to \a parent. + The default audio output device is used with the output + \a format parameters. +*/ + +QAudioOutput::QAudioOutput(const QAudioFormat &format, QObject *parent): + QObject(parent) +{ + d = QAudioDeviceFactory::createDefaultOutputDevice(format); + connect(d, SIGNAL(notify()), SIGNAL(notify())); + connect(d, SIGNAL(stateChanged(QAudio::State)), SIGNAL(stateChanged(QAudio::State))); +} + +/*! + Construct a new audio output and attach it to \a parent. + The device referenced by \a audioDevice is used with the output + \a format parameters. +*/ + +QAudioOutput::QAudioOutput(const QAudioDeviceInfo &audioDevice, const QAudioFormat &format, QObject *parent): + QObject(parent) +{ + d = QAudioDeviceFactory::createOutputDevice(audioDevice, format); + connect(d, SIGNAL(notify()), SIGNAL(notify())); + connect(d, SIGNAL(stateChanged(QAudio::State)), SIGNAL(stateChanged(QAudio::State))); +} + +/*! + Destroys this audio output. +*/ + +QAudioOutput::~QAudioOutput() +{ + delete d; +} + +/*! + Returns the QAudioFormat being used. + +*/ + +QAudioFormat QAudioOutput::format() const +{ + return d->format(); +} + +/*! + Uses the \a device as the QIODevice to transfer data. + Passing a QIODevice allows the data to be transferred without any extra code. + All that is required is to open the QIODevice. + + If able to successfully output audio data to the systems audio device the + state() is set to QAudio::ActiveState, error() is set to QAudio::NoError + and the stateChanged() signal is emitted. + + If a problem occurs during this process the error() is set to QAudio::OpenError, + state() is set to QAudio::StoppedState and stateChanged() signal is emitted. + + In either case, the stateChanged() signal may be emitted either synchronously + during execution of the start() function or asynchronously after start() has + returned to the caller. + + \sa QIODevice +*/ + +void QAudioOutput::start(QIODevice* device) +{ + d->start(device); +} + +/*! + Returns a pointer to the QIODevice being used to handle the data + transfer. This QIODevice can be used to write() audio data directly. + + If able to access the systems audio device the state() is set to + QAudio::IdleState, error() is set to QAudio::NoError + and the stateChanged() signal is emitted. + + If a problem occurs during this process the error() is set to QAudio::OpenError, + state() is set to QAudio::StoppedState and stateChanged() signal is emitted. + + In either case, the stateChanged() signal may be emitted either synchronously + during execution of the start() function or asynchronously after start() has + returned to the caller. + + \sa QIODevice +*/ + +QIODevice* QAudioOutput::start() +{ + return d->start(0); +} + +/*! + Stops the audio output, detaching from the system resource. + + Sets error() to QAudio::NoError, state() to QAudio::StoppedState and + emit stateChanged() signal. +*/ + +void QAudioOutput::stop() +{ + d->stop(); +} + +/*! + Drops all audio data in the buffers, resets buffers to zero. +*/ + +void QAudioOutput::reset() +{ + d->reset(); +} + +/*! + Stops processing audio data, preserving buffered audio data. + + Sets error() to QAudio::NoError, state() to QAudio::SuspendedState and + emit stateChanged() signal. +*/ + +void QAudioOutput::suspend() +{ + d->suspend(); +} + +/*! + Resumes processing audio data after a suspend(). + + Sets error() to QAudio::NoError. + Sets state() to QAudio::ActiveState if you previously called start(QIODevice*). + Sets state() to QAudio::IdleState if you previously called start(). + emits stateChanged() signal. + + Note: signal will always be emitted during execution of the resume() function. +*/ + +void QAudioOutput::resume() +{ + d->resume(); +} + +/*! + Returns the free space available in bytes in the audio buffer. + + NOTE: returned value is only valid while in QAudio::ActiveState or QAudio::IdleState + state, otherwise returns zero. +*/ + +int QAudioOutput::bytesFree() const +{ + return d->bytesFree(); +} + +/*! + Returns the period size in bytes. + + Note: This is the recommended write size in bytes. +*/ + +int QAudioOutput::periodSize() const +{ + return d->periodSize(); +} + +/*! + Sets the audio buffer size to \a value in bytes. + + Note: This function can be called anytime before start(), calls to this + are ignored after start(). It should not be assumed that the buffer size + set is the actual buffer size used, calling bufferSize() anytime after start() + will return the actual buffer size being used. +*/ + +void QAudioOutput::setBufferSize(int value) +{ + d->setBufferSize(value); +} + +/*! + Returns the audio buffer size in bytes. + + If called before start(), returns platform default value. + If called before start() but setBufferSize() was called prior, returns value set by setBufferSize(). + If called after start(), returns the actual buffer size being used. This may not be what was set previously + by setBufferSize(). + +*/ + +int QAudioOutput::bufferSize() const +{ + return d->bufferSize(); +} + +/*! + Sets the interval for notify() signal to be emitted. + This is based on the \a ms of audio data processed + not on actual real-time. + The minimum resolution of the timer is platform specific and values + should be checked with notifyInterval() to confirm actual value + being used. +*/ + +void QAudioOutput::setNotifyInterval(int ms) +{ + d->setNotifyInterval(ms); +} + +/*! + Returns the notify interval in milliseconds. +*/ + +int QAudioOutput::notifyInterval() const +{ + return d->notifyInterval(); +} + +/*! + Returns the amount of audio data processed by the class since start() + was called in microseconds. + + Note: The amount of audio data played can be determined by subtracting + the microseconds of audio data still in the systems audio buffer. + + \code + qint64 bytesInBuffer = bufferSize() - bytesFree(); + qint64 usInBuffer = (qint64)(1000000) * bytesInBuffer / ( channels() * sampleSize() / 8 ) / frequency(); + qint64 usPlayed = processedUSecs() - usInBuffer; + \endcode +*/ + +qint64 QAudioOutput::processedUSecs() const +{ + return d->processedUSecs(); +} + +/*! + Returns the microseconds since start() was called, including time in Idle and + Suspend states. +*/ + +qint64 QAudioOutput::elapsedUSecs() const +{ + return d->elapsedUSecs(); +} + +/*! + Returns the error state. +*/ + +QAudio::Error QAudioOutput::error() const +{ + return d->error(); +} + +/*! + Returns the state of audio processing. +*/ + +QAudio::State QAudioOutput::state() const +{ + return d->state(); +} + +/*! + \fn QAudioOutput::stateChanged(QAudio::State state) + This signal is emitted when the device \a state has changed. + This is the current state of the audio output. +*/ + +/*! + \fn QAudioOutput::notify() + This signal is emitted when x ms of audio data has been processed + the interval set by setNotifyInterval(x). +*/ + +QT_END_NAMESPACE |