AudioStreamInfo Class Reference

AudioStreamInfo describes an elementary audio stream. More...

Inherits StreamInfo.

List of all members.

Public Member Functions
virtual int32_t	pcmFlags () const =0
	Returns the audio format flags which describe various properties of the audio stream.
virtual void	setPcmFlags (int32_t flags)=0
	Sets the audio format flags which describe various properties of the audio stream.
virtual int32_t	channels () const =0
	Returns the number of audio channels.
virtual void	setChannels (int32_t numChannels)=0
	Sets the number of audio channels.
virtual int32_t	channelLayout () const =0
	Returns the channel layout which defines the mapping between channels and speakers.
virtual void	setChannelLayout (int32_t channelLayout)=0
	Sets the channel layout which defines the mapping between channels and speakers.
virtual int32_t	sampleRate () const =0
	Returns the audio sample rate.
virtual void	setSampleRate (int32_t sampleRate)=0
	Sets the audio sample rate.
virtual int32_t	bitsPerSample () const =0
	Returns the number of bits per sample (sample resolution).
virtual void	setBitsPerSample (int32_t bitsPerSample)=0
	Sets the number of bits per sample (sample resolution).
virtual int32_t	bytesPerFrame () const =0
	Returns the number of bytes occupied by an audio frame (smallest discrete unit).
virtual void	setBytesPerFrame (int32_t bytesPerFrame)=0
	Sets the number of bytes occupied by an audio frame (smallest discrete unit).
virtual bool_t	copyTo (AudioStreamInfo *destination) const =0
	Copies the state of the current object to a destination object of the same type.
virtual AudioStreamInfo *	clone () const =0
	Creates a copy of this object.
Protected Member Functions
	~AudioStreamInfo ()
	This object can be destroyed only by its implementation.

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Detailed Description

AudioStreamInfo describes an elementary audio stream.

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Constructor & Destructor Documentation

~AudioStreamInfo

(

)

[protected]

This object can be destroyed only by its implementation.

The caller must use Reference::release.

See also:

Object Management

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Member Function Documentation

virtual int32_t bitsPerSample

(

)

const [pure virtual]

Returns the number of bits per sample (sample resolution).

Returns:

bits per sample (usually 8, 16, 24 or 32).

Normally bits per sample is not defined for a compressed audio stream and is 0. However it is possible for a compressed audio stream to return a positive value as an indication of audio quality. It can also designate the bits per sample of the LPCM stream once the compressed stream is decoded.

virtual int32_t bytesPerFrame

(

)

const [pure virtual]

Returns the number of bytes occupied by an audio frame (smallest discrete unit).

Returns:

bytes per frame.

A frame is the smallest unit in an audio stream. It may contain one or more samples. Depending on the audio stream type the frame may contain fixed or variable number of samples.

For compressed streams the frame size is variable even if there are fixed number of samples in each frame. In this case bytes per frame is 0.

For an LCPM stream the frame size is constant. In this case bytes per frame is a positive value. Normally for interleaved LPCM streams the following is true:

• bytesPerFrame() / channels() == (sample size in bytes)
• The valid bits in a sample are given by bitsPerSample() and they are aligned towards the hi-order byte.

virtual int32_t channelLayout

(

)

const [pure virtual]

Returns the channel layout which defines the mapping between channels and speakers.

Returns:

A combination of flags defined in the AudioChannelFlags::Enum.

virtual int32_t channels

(

)

const [pure virtual]

Returns the number of audio channels.

Returns:

Number of channels.

virtual AudioStreamInfo* clone

(

)

const [pure virtual]

Creates a copy of this object.

Returns:

A new AudioStreamInfo. The caller is responsible for releasing the new object when it is not needed anymore.

See also:

Object Management

Implements StreamInfo.

virtual bool_t copyTo

(

AudioStreamInfo *

destination

)

const [pure virtual]

Copies the state of the current object to a destination object of the same type.

The reference count of the source and the destination is not modified.

Parameters:

destination

[out] A pointer to the destination object

Returns:

TRUE if the object state is copied, FALSE otherwise.

virtual int32_t pcmFlags

(

)

const [pure virtual]

Returns the audio format flags which describe various properties of the audio stream.

Returns:

A combination of flags defined in PcmFlags::Enum.

virtual int32_t sampleRate

(

)

const [pure virtual]

Returns the audio sample rate.

Returns:

sample rate (Hz)

virtual void setBitsPerSample

(

int32_t

bitsPerSample

)

[pure virtual]

Sets the number of bits per sample (sample resolution).

Parameters:

bitsPerSample

(usually 8, 16, 24 or 32)

virtual void setBytesPerFrame

(

int32_t

bytesPerFrame

)

[pure virtual]

Sets the number of bytes occupied by an audio frame (smallest discrete unit).

Parameters:

bytesPerFrame

[in] Specifies how many bytes are occupied by each audio frame. Normally it is valid (greater than 0) for LPCM streams and invalid (0) for compressed audio streams.

virtual void setChannelLayout

(

int32_t

channelLayout

)

[pure virtual]

Sets the channel layout which defines the mapping between channels and speakers.

Parameters:

channelLayout

A combination of flags defined in the AudioChannelFlags::Enum.

virtual void setChannels

(

int32_t

numChannels

)

[pure virtual]

Sets the number of audio channels.

Parameters:

numChannels

number of channels.

virtual void setPcmFlags

(

int32_t

flags

)

[pure virtual]

Sets the audio format flags which describe various properties of the audio stream.

Parameters:

flags

A combination of flags defined in PcmFlags::Enum.

virtual void setSampleRate

(

int32_t

sampleRate

)

[pure virtual]

Sets the audio sample rate.

Parameters:

sampleRate

sample rate (Hz)