The QAudioInput 类为从音频输入设备接收音频数据提供接口。 更多...
| 头： | #include <QAudioInput> |
| Since: | Qt 4.6 |
| 继承： | QObject |
| QAudioInput (const QAudioFormat & format = QAudioFormat(), QObject * parent = 0) | |
| QAudioInput (const QAudioDeviceInfo & audioDevice , const QAudioFormat & format = QAudioFormat(), QObject * parent = 0) | |
| ~QAudioInput () | |
| int | bufferSize () const |
| int | bytesReady () const |
| qint64 | elapsedUSecs () const |
| QAudio::Error | error () const |
| QAudioFormat | format () const |
| int | notifyInterval () const |
| int | periodSize () const |
| qint64 | processedUSecs () const |
| void | reset () |
| void | resume () |
| void | setBufferSize (int value ) |
| void | setNotifyInterval (int ms ) |
| void | start (QIODevice * device ) |
| QIODevice * | start () |
| QAudio::State | state () const |
| void | stop () |
| void | suspend () |
| void | notify () |
| void | stateChanged (QAudio::State state ) |
The QAudioInput 类为从音频输入设备接收音频数据提供接口。
可以构造音频输入采用系统的 默认音频输入设备 。它也是可能的，创建 QAudioInput 采用特有 QAudioDeviceInfo 。当创建音频输入时，还应发送 QAudioFormat 用于录制 (见 QAudioFormat 类描述了解细节)。
要录制到文件：
QAudioInput lets you record audio with an audio input device. The default constructor of this class will use the systems default audio device, but you can also specify a QAudioDeviceInfo for a specific device. You also need to pass in the QAudioFormat in which you wish to record.
Starting up the QAudioInput is simply a matter of calling start () 采用 QIODevice opened for writing. For instance, to record to a file, you can:
QFile outputFile; // class member.
QAudioInput *audioInput; // class member.
...
void startRecording()
{
outputFile.setFileName("/tmp/test.raw");
outputFile.open( QIODevice::WriteOnly | QIODevice::Truncate );
QAudioFormat format;
// set up the format you want, 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::defaultInputDevice();
if (!info.isFormatSupported(format)) {
qWarning()<<"default format not supported try to use nearest";
format = info.nearestFormat(format);
}
audioInput = new QAudioInput(format, this);
QTimer::singleShot(3000, this, SLOT(stopRecording()));
audioInput->start(&outputFile);
// Records audio for 3000ms
}
This will start recording if the format specified is supported by the input device (you can check this with
QAudioDeviceInfo::isFormatSupported
(). In case there are any snags, use the
error
() function to check what went wrong. We stop recording in the
stopRecording()
槽。
void stopRecording()
{
audioInput->stop();
outputFile.close();
delete audioInput;
}
At any point in time, QAudioInput will be in one of four states: active, suspended, stopped, or idle. These states are specified by the QAudio::State enum. You can request a state change directly through suspend (), resume (), stop (), reset ()，和 start (). The current state is reported by state (). QAudioOutput will also signal you when the state changes ( stateChanged ()).
QAudioInput
provides several ways of measuring the time that has passed since the
start
() of the recording. The
processedUSecs()
function returns the length of the stream in microseconds written, i.e., it leaves out the times the audio input was suspended or idle. The
elapsedUSecs
() function returns the time elapsed since
start
() was called regardless of which states the
QAudioInput
has been in.
If an error should occur, you can fetch its reason with error (). The possible error reasons are described by the QAudio::Error enum. The QAudioInput will enter the StoppedState when an error is encountered. Connect to the stateChanged () signal to handle the error:
void stateChanged(QAudio::State newState)
{
switch(newState) {
case QAudio::StoppedState:
if (audioInput->error() != QAudio::NoError) {
// Perform error handling
} else {
}
break;
On Symbian, processes which use this class must have the
UserEnvironment
platform security capability. If the client process lacks this capability, calls to either overload of
start
() will fail. This failure is indicated by the
QAudioInput
object setting its
error
() value to
QAudio::OpenError
and then emitting a
stateChanged
(
QAudio::StoppedState
) 信号。
Platform security capabilities are added via the TARGET.CAPABILITY qmake variable.
另请参阅 QAudioOutput and QAudioDeviceInfo .
Construct a new audio input and attach it to parent . The default audio input device is used with the output format 参数。
Construct a new audio input and attach it to parent . The device referenced by audioDevice is used with the input format 参数。
Destroy this audio input.
Returns the audio buffer size in milliseconds.
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 ().
另请参阅 setBufferSize ().
Returns the amount of audio data available to read in bytes.
NOTE: returned value is only valid while in QAudio::ActiveState or QAudio::IdleState state, otherwise returns zero.
Returns the microseconds since start () was called, including time in Idle and Suspend states.
返回错误状态。
返回 QAudioFormat 被使用。
[signal]
void
QAudioInput::
notify
()
This signal is emitted when x ms of audio data has been processed the interval set by setNotifyInterval (x).
Returns the notify interval in milliseconds.
另请参阅 setNotifyInterval ().
Returns the period size in bytes.
Note: This is the recommended read size in bytes.
Returns the amount of audio data processed since start () was called in microseconds.
Drops all audio data in the buffers, resets buffers to zero.
Resumes processing audio data after a suspend ().
集 error () 到 QAudio::NoError . Sets state () 到 QAudio::ActiveState if you previously called start( QIODevice *). Sets state () 到 QAudio::IdleState if you previously called start (). emits stateChanged () 信号。
Sets the audio buffer size to value 毫秒。
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.
另请参阅 bufferSize ().
Sets the interval for notify () signal to be emitted. This is based on the 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.
另请参阅 notifyInterval ().
使用 device 作为 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 . QAudioInput 未拥有所有权对于 device .
The QAudioInput will write to the device when new data is available. You can subclass QIODevice 并重实现 writeData() if you wish to access the data. If you simply want to save data to a file, you can pass a QFile to this function.
If able to successfully get audio data from the systems audio device the state () is set to either QAudio::ActiveState or QAudio::IdleState , error () 被设为 QAudio::NoError 和 stateChanged () 信号发射。
If a problem occurs during this process the error () 被设为 QAudio::OpenError , state () 被设为 QAudio::StoppedState and stateChanged () 信号发射。
QAudioInput#Symbian Platform Security Requirements
另请参阅 QIODevice .
Returns a pointer to a new QIODevice that will be used to handle the data transfer. This QIODevice can be used to read() audio data directly. You will typically connect to the readyRead() signal, and read from the device in the slot you connect to. QAudioInput keeps ownership of the device.
If able to access the systems audio device the state () 被设为 QAudio::IdleState , error () 被设为 QAudio::NoError 和 stateChanged () 信号发射。
If a problem occurs during this process the error () 被设为 QAudio::OpenError , state () 被设为 QAudio::StoppedState and stateChanged () 信号发射。
QAudioInput#Symbian Platform Security Requirements
另请参阅 QIODevice .
返回音频处理的状态。
[signal]
void
QAudioInput::
stateChanged
(
QAudio::State
state
)
此信号被发射当设备 state 已改变。
Stops the audio input, detaching from the system resource.
集 error () 到 QAudio::NoError , state () 到 QAudio::StoppedState and emit stateChanged () 信号。
Stops processing audio data, preserving buffered audio data.
集 error () 到 QAudio::NoError , state () 到 QAudio::SuspendedState and emit stateChanged () 信号。