AudioDataOutput Class Reference

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Detailed Description

This class gives you the audio data (for visualizations).

This class implements a special AbstractAudioOutput that gives your application the audio data. Don't expect realtime performance. But the latencies should be low enough to use the audio data for visualizations. You can also use the audio data for further processing (e.g. encoding and saving to a file).

Author:

Matthias Kretz <kretz@kde.org>

Definition at line 52 of file audiodataoutput.h.

#include <audiodataoutput.h>

Inheritance diagram for AudioDataOutput:

List of all members.

Public Types
enum	Channel {   LeftChannel, RightChannel, CenterChannel, LeftSurroundChannel,   RightSurroundChannel, SubwooferChannel }
	Specifies the channel the audio data belongs to. More...
Public Slots
void	setDataSize (int size)
	Sets the number of samples to be passed in one signal emission.
Signals
void	dataReady (const QMap< Phonon::AudioDataOutput::Channel, QVector< qint16 > > &data)
	Emitted whenever another dataSize number of samples are ready.
void	endOfMedia (int remainingSamples)
	This signal is emitted before the last dataReady signal of a media is emitted.
Public Member Functions
int	dataSize () const
	Returns the currently used number of samples passed through the signal.
int	sampleRate () const
	Returns the sample rate in Hz.
Properties
int	dataSize

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Member Enumeration Documentation

enum Channel

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Specifies the channel the audio data belongs to.

Enumerator:

LeftChannel	Search for all occurrences
RightChannel	Search for all occurrences
CenterChannel	Search for all occurrences
LeftSurroundChannel	Search for all occurrences
RightSurroundChannel	Search for all occurrences
SubwooferChannel	Search for all occurrences

Definition at line 63 of file audiodataoutput.h.

            {
                LeftChannel,
                RightChannel,
                CenterChannel,
                LeftSurroundChannel,
                RightSurroundChannel,
                SubwooferChannel
            };

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Member Function Documentation

int dataSize

(

)

const

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Returns the currently used number of samples passed through the signal.

See also:

setDataSize

int sampleRate

(

)

const

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Returns the sample rate in Hz.

Common sample rates are 44100 Hz and 48000 Hz. AudioDataOutput will not do any sample rate conversion for you. If you need to convert the sample rate you might want to take a look at libsamplerate. For visualizations it is often enough to do simple interpolation or even drop/duplicate samples.

Returns:

The sample rate as reported by the backend. If the backend is unavailable -1 is returned.

void setDataSize

(

int

size

)

[slot]

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Sets the number of samples to be passed in one signal emission.

Defaults to 512 samples per emitted signal.

Parameters:

size	the number of samples

void dataReady

(

const QMap< Phonon::AudioDataOutput::Channel, QVector< qint16 > > &

data

)

[signal]

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Emitted whenever another dataSize number of samples are ready.

Parameters:

data	A mapping of Channel to a vector holding the audio data.

void endOfMedia

(

int

remainingSamples

)

[signal]

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This signal is emitted before the last dataReady signal of a media is emitted.

If, for example, the playback of a media file has finished and the last audio data of that file is going to be passed with the next dataReady signal, and only the 28 first samples of the data vector are from that media file endOfMedia will be emitted right before dataReady with remainingSamples = 28.

Parameters:

remainingSamples

The number of samples in the next dataReady vector that belong to the media that was playing to this point.

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Property Documentation

int dataSize [read, write]

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Definition at line 57 of file audiodataoutput.h.

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The documentation for this class was generated from the following file:

• phonon/audiodataoutput.h