The QAudioFormat class stores audio stream parameter information. More...

Public Types
enum	Endian

enum	SampleType

Public Methods
	QAudioFormat ()

	QAudioFormat (const QAudioFormat &other)

	~QAudioFormat ()

QAudioFormat::Endian	byteOrder () const

qint32	bytesForDuration (qint64 duration) const

qint32	bytesForFrames (qint32 frameCount) const

int	bytesPerFrame () const

int	channelCount () const

QString	codec () const

qint64	durationForBytes (qint32 byteCount) const

qint64	durationForFrames (qint32 frameCount) const

qint32	framesForBytes (qint32 byteCount) const

qint32	framesForDuration (qint64 duration) const

bool	isValid () const

bool	operator!= (const QAudioFormat &other) const

QAudioFormat &	operator= (const QAudioFormat &other)

bool	operator== (const QAudioFormat &other) const

int	sampleRate () const

int	sampleSize () const

QAudioFormat::SampleType	sampleType () const

void	setByteOrder (QAudioFormat::Endian byteOrder)

void	setChannelCount (int channelCount)

void	setCodec (const QString &codec)

void	setSampleRate (int sampleRate)

void	setSampleSize (int sampleSize)

void	setSampleType (QAudioFormat::SampleType sampleType)

Detailed Description

An audio format specifies how data in an audio stream is arranged, i.e, how the stream is to be interpreted. The encoding itself is specified by the codec() used for the stream.

In addition to the encoding, QAudioFormat contains other parameters that further specify how the audio sample data is arranged. These are the frequency, the number of channels, the sample size, the sample type, and the byte order. The following table describes these in more detail.

Parameter	Description
`Sample Rate`	Samples per second of audio data in Hertz
`Number of channels`	The number of audio channels (typically one for mono or two for stereo)
`Sample size`	How much data is stored in each sample (typically 8 or 16 bits)
`Sample type`	Numerical representation of sample (typically signed integer, unsigned integer or float)
`Byte order`	Byte ordering of sample (typically little endian, big endian)

This class is typically used in conjunction with QAudioInput or QAudioOutput to allow you to specify the parameters of the audio stream being read or written, or with QAudioBuffer when dealing with samples in memory.

You can obtain audio formats compatible with the audio device used through functions in QAudioDeviceInfo. This class also lets you query available parameter values for a device, so that you can set the parameters yourself. You need to know the format of the audio streams you wish to play or record.

In the common case of interleaved linear PCM data, the codec will be "audio/pcm", and the samples for all channels will be interleaved. One sample for each channel for the same instant in time is referred to as a frame.

See also: QAudioDeviceInfo

Member Enumeration Documentation

enum QAudioFormat::Endian

Enums for describing the format of samples.

Constant	Value	Description
`QAudioFormat::BigEndian`	QSysInfo::BigEndian	Samples are big endian byte order
`QAudioFormat::LittleEndian`	QSysInfo::LittleEndian	Samples are little endian byte order

enum QAudioFormat::SampleType

Enums for describing the format of samples.

Constant	Value	Description
`QAudioFormat:Unknown`	0	Not Set
`QAudioFormat:SignedInt`	1	Samples are signed integers
`QAudioFormat:UnSignedInt`	2	Samples are unsigned integers
`QAudioFormat:Float`	3	Samples are floats

Constructor & Destructor Documentation

QAudioFormat::QAudioFormat ( )

Construct a new audio format with values are initialized as shown.

sampleRate() = -1
channelCount() = -1
sampleSize() = -1
byteOrder() = QAudioFormat::Endian(QSysInfo::ByteOrder)
sampleType() = QAudioFormat::Unknown
codec() = ""

QAudioFormat::QAudioFormat ( const QAudioFormat & other )

Construct a new audio format using other.

QAudioFormat::~QAudioFormat ( )

Destroy this audio format.

Method Documentation

QAudioFormat::Endian QAudioFormat::byteOrder ( ) const

Returns the current byteOrder value.

qint32 QAudioFormat::bytesForDuration ( qint64 duration ) const

Returns the number of bytes required for this audio format for duration microseconds. Returns 0 if this format is not valid. Some rounding may occur if duration is not an exact fraction of the sampleRate().

See also: durationForBytes()

qint32 QAudioFormat::bytesForFrames ( qint32 frameCount ) const

Returns the number of bytes required for frameCount frames of this format. Returns 0 if this format is not valid.

See also: bytesForDuration()

int QAudioFormat::bytesPerFrame ( ) const

Returns the number of bytes required to represent one frame (a sample in each channel) in this format. Returns 0 if this format is invalid.

int QAudioFormat::channelCount ( ) const

Returns the current channel count value.

QString QAudioFormat::codec ( ) const

Returns the current codec identifier.

See also: QAudioDeviceInfo::supportedCodecs()

qint64 QAudioFormat::durationForBytes ( qint32 byteCount ) const

Returns the number of microseconds represented by byteCountss in this format. Returns 0 if this format is not valid. Some rounding may occur if bytes is not an exact multiple of the number of bytes per frame.

See also: bytesForDuration()

qint64 QAudioFormat::durationForFrames ( qint32 frameCount ) const

Return the number of microseconds represented by frameCount frames in this format.

qint32 QAudioFormat::framesForBytes ( qint32 byteCount ) const

Returns the number of frames represented by byteCount in this format. Each frame has one sample per channel. Some rounding may occur if byteCount is not an exact multiple of the number of bytes per frame.

See also: framesForDuration()

qint32 QAudioFormat::framesForDuration ( qint64 duration ) const

Returns the number of frames required to represent duration microseconds in this format.

Some rounding may occur if duration is not an exact fraction of the sampleRate().

bool QAudioFormat::isValid ( ) const

Returns true if all of the parameters are valid.

bool QAudioFormat::operator!= ( const QAudioFormat & other ) const

Returns true if this QAudioFormat is not equal to the other QAudioFormat, otherwise returns false. All elements of QAudioFormat are used for the comparison.

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

Copy assigns from other and returns a reference to this object.

bool QAudioFormat::operator== ( const QAudioFormat & other ) const

Returns true if this QAudioFormat is equal to the other QAudioFormat, otherwise returns false. All elements of QAudioFormat are used for the comparison.

int QAudioFormat::sampleRate ( ) const

Returns the current sample rate in Hertz.

int QAudioFormat::sampleSize ( ) const

Returns the current sample size value, in bits.

See also: bytesPerFrame()

QAudioFormat::SampleType QAudioFormat::sampleType ( ) const

Returns the current SampleType value.

void QAudioFormat::setByteOrder ( QAudioFormat::Endian byteOrder )

Sets the byteOrder to byteOrder.

void QAudioFormat::setChannelCount ( int channelCount )

Sets the channel count to channelCount.

void QAudioFormat::setCodec ( const QString & codec )

Sets the codec to the given codec. The codec should be one of the types reported by the QAudioDeviceInfo::supportedCodecs() method for the audio device you are working with.

See also: QAudioDeviceInfo::supportedCodecs()

void QAudioFormat::setSampleRate ( int sampleRate )

Sets the sample rate to sampleRate Hertz.

void QAudioFormat::setSampleSize ( int sampleSize )

Sets the sample size to the sampleSize specified, in bits. This is typically 8 or 16, but some systems may support higher sample sizes.

void QAudioFormat::setSampleType ( QAudioFormat::SampleType sampleType )

Sets the sampleType to sampleType.

Public Types

Public Methods

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Method Documentation