CopperSpice API  1.7.2
QAudioFormat Class Reference

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

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

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.

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.

Note that 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  bytes) const

Returns the number of microseconds represented by bytes 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)

Assigns other to this QAudioFormat implementation.

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  channels)

Sets the channel count to channels.

void QAudioFormat::setCodec ( const QString codec)

Sets the codec to codec.

The parameter to this function 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.