CopperSpice API  1.7.2
QAudioBuffer Class Reference

The QAudioBuffer class represents a collection of audio samples with a specific format and sample rate. More...

Classes

class  StereoFrame
 Simple wrapper for a stereo audio frame More...
 

Public Typedefs

typedef StereoFrame< signed short > S16S
 
typedef StereoFrame< unsigned short > S16U
 
typedef StereoFrame< float > S32F
 
typedef StereoFrame< signed char > S8S
 
typedef StereoFrame< unsigned char > S8U
 

Public Methods

 QAudioBuffer ()
 
 QAudioBuffer (const QAudioBuffer &other)
 
 QAudioBuffer (const QByteArray &data, const QAudioFormat &format, qint64 startTime=-1)
 
 QAudioBuffer (int numFrames, const QAudioFormat &format, qint64 startTime=-1)
 
 ~QAudioBuffer ()
 
int byteCount () const
 
const void * constData () const
 
void * data ()
 
qint64 duration () const
 
QAudioFormat format () const
 
int frameCount () const
 
bool isValid () const
 
QAudioBuffer & operator= (const QAudioBuffer &other)
 
int sampleCount () const
 
qint64 startTime () const
 

Detailed Description

The QAudioBuffer class represents a collection of audio samples with a specific format and sample rate.

Member Typedef Documentation

This is a predefined specialization for a signed stereo 16 bit sample. Each channel is a signed short.

This is a predefined specialization for an unsigned stereo 16 bit sample. Each channel is an unsigned short.

This is a predefined specialization for an 32 bit float sample. Each channel is a float.

This is a predefined specialization for a signed stereo 8 bit sample. Each channel is a signed char.

This is a predefined specialization for an unsigned stereo 8 bit sample. Each channel is an unsigned char.

Constructor & Destructor Documentation

QAudioBuffer::QAudioBuffer ( )

Create a new, empty, invalid buffer.

QAudioBuffer::QAudioBuffer ( const QAudioBuffer &  other)

Creates a new audio buffer from other. Generally this will have copy-on-write semantics and a copy will only be made when it has to be.

QAudioBuffer::QAudioBuffer ( const QByteArray data,
const QAudioFormat format,
qint64  startTime = -1 
)

Creates a new audio buffer from a copy of the supplied data in the given format. The format will determine how the number and sizes of the samples are interpreted from the data. If the supplied data is not an integer multiple of the calculated frame size, the excess data will not be used.

The startTime (in microseconds) indicates when this buffer starts in the stream. If this buffer is not part of a stream, set it to -1.

QAudioBuffer::QAudioBuffer ( int  numFrames,
const QAudioFormat format,
qint64  startTime = -1 
)

Creates a new audio buffer with space for numFrames frames of the given format. The individual samples will be initialized to the default for the format.

The startTime (in microseconds) indicates when this buffer starts in the stream. If this buffer is not part of a stream, then set it to -1.

QAudioBuffer::~QAudioBuffer ( )

Destroys this audio buffer.

Method Documentation

int QAudioBuffer::byteCount ( ) const

Returns the size of this buffer, in bytes.

const void * QAudioBuffer::constData ( ) const

Returns a read only pointer to the buffers data. This method is preferred over the const version of data() to prevent unnecessary copying. There is no checking done on the format of the audio buffer.

// With a 16bit sample buffer
const quint16 *data = buffer->constData<quint16>();
void * QAudioBuffer::data ( )

Returns a pointer to this buffer's data. You can modify the data through the returned pointer.

Since QAudioBuffers can share the actual sample data, calling this function will result in a deep copy being made if there are any other buffers using the sample. You should avoid calling this unless you really need to modify the data.

This pointer will remain valid until the underlying storage is detached. In particular, if you obtain a pointer, and then copy this audio buffer, changing data through this pointer may change both buffer instances. Calling data() on either instance will again cause a deep copy to be made, which may invalidate the pointers returned from this function previously.

// With a 16bit sample buffer
quint16 *data = buffer->data<quint16>(); // may cause deep copy
qint64 QAudioBuffer::duration ( ) const

Returns the duration of audio in this buffer, in microseconds. This depends on the format() and the frameCount().

QAudioFormat QAudioBuffer::format ( ) const

Returns the QAudioFormat of this buffer. Several properties of this format influence how the duration() or byteCount() are calculated from the frameCount().

int QAudioBuffer::frameCount ( ) const

Returns the number of complete audio frames in this buffer.

An audio frame is an interleaved set of one sample per channel for the same instant in time.

bool QAudioBuffer::isValid ( ) const

Returns true if this is a valid buffer. A valid buffer has more than zero frames in it and a valid format.

QAudioBuffer & QAudioBuffer::operator= ( const QAudioBuffer &  other)

Assigns the other buffer to this.

int QAudioBuffer::sampleCount ( ) const

Returns the number of samples in this buffer.

If the format of this buffer has multiple channels, then this count includes all channels. This means that a stereo buffer with 1000 samples in total will have 500 left samples and 500 right samples (interleaved), and this method will return 1000.

See also
frameCount()
qint64 QAudioBuffer::startTime ( ) const

Returns the time in a stream that this buffer starts at (in microseconds). If this buffer is not part of a stream, this will return -1.