#include <VisualAudioLab.h>

Collaboration diagram for VizKit::VisualAudioLab:

Classes
struct	BeatGuess
struct	RMSValue
Public Member Functions
void	processAudioData (uint8 numWaveformChannels, uint16 numWaveformEntries, const uint8 const currWaveformData, uint8 numSpectrumChannels, uint16 numSpectrumEntries, const uint8 const currSpectrumData)
void	resetData (void)
uint32	getCurrTimestampIDOfRenderData (void)
void	setCurrTimestampIDOfRenderData (const uint32 timestampID)
void	setTotalTimeOfCurrentTrack (const uint32 totalTimeInMS)
void	setStartTimeOfCurrentTrack (const uint32 startTimeInMS)
void	setStopTimeOfCurrentTrack (const uint32 stopTimeInMS)
bool	remainingTimeOfCurrentTrackIsKnown (void)
uint32	getRemainingTimeOfCurrentTrack (void)
uint32	getTotalTimeOfCurrentTrack (void)
sint16	getCurrMusicDataHistory (void)
sint16	getPrevMusicDataHistory (void)
uint8	getRMSIntensity (void)
uint8	getWaveformDataOfChannelAtIndex (const uint16 channel, const uint16 index)
const uint8 ***const	getSpectrumDataArray (void)
const sint16 **const	getWaveformDataMonoArray (void)
uint8	getMonoWaveformDataAtIndex (const uint16 index)
uint8	getWaveformDataOfChannelAtIndexWithHistoryNum (const uint16 channel, const uint16 index, const uint16 historyNum)
uint8	getMonoWaveformDataAtIndexWithHistoryNum (const uint16 index, const uint16 historyNum)
uint8	getDCIntensity (void)
void	checkForBeatImpulse (void)
uint8	getBeatMeter (void)
void	HannWindow (const int N, double TimeSamples[])
const sint8 *const	getWaveformShapeArray (void)
uint32	getNumberOfAudioSpectrumDataEntries (void)
uint32	getNumberOfWaveformEntries (void)
uint32	getNumberOfSpectrumEntries (void)
uint16	getMaxNumberOfWaveformShapeHistory (void)
uint16	getNumberOfDataChannels (void)
uint16	getMaxNumberOfMusicDataHistories (void)
const uint32 *const	getBeatHistogram (void)
Static Public Member Functions
static VisualAudioLab *	getInstance (void)
static void	dispose (void)
static void	setMaxNumberOfAudioDataChannels (uint16 aNumberOfMaxAudioDataChannels)
static void	setNumberOfAudioWaveformDataEntries (uint32 aNumberOfAudioWaveformDataEntries)
static void	setNumberOfAudioSpectrumDataEntries (uint32 aNumberOfAudioSpectrumDataEntries)
Private Member Functions
	VisualAudioLab ()
	~VisualAudioLab ()
	VisualAudioLab (const VisualAudioLab &other)
VisualAudioLab &	operator= (const VisualAudioLab &other)
void	init (void)
void	processWaveformData (uint8 numWaveformChannels, uint16 numWaveformEntries, const uint8 *const currWaveformData)
void	processSpectrumData (const uint8 numSpectrumChannels, const uint16 numSpectrumEntries, const uint8 *const currSpectrumData)
void	incrementMusicDataHistory (void)
void	storeBeatImpulse (bool beatImpulse)
void	addToWaveformShape (sint8 minWaveformPoint, sint8 maxWaveformPoint)
void	addToBeatRecords (void)
void	addToBeatGapHistogram (uint16 gapInMilliseconds)
void	resetBeatGapHistogram (void)
void	calcBeatConfidence (void)
uint32	getBestBeatMSInterval (void)
uint8	isBeatMeter (uint32 elapsedMSSinceStartOfTrack)
Private Attributes
uint32	totalTimeOfTrack
uint32	elapsedTimeOfTrack
uint32	startTimeOfTrack
uint32	stopTimeOfTrack
uint32	currTimestampIDOfRenderData
sint8	numberOfMusicDataHistoryInt
sint8 ***	waveformData
sint16 **	waveformDataMono
uint8 ***	spectrumData
double *	amplitudeEnvelope
sint32 *	mean
double *	tappingBuffer
double **	rms
double *	rmsMono
double	rmsMonoAvg
uint32 *	beatGapHistogram
uint32	beatTimeDeltaInMS
double	rmsMonoMax
sint16	currMusicDataHistory
uint8 *	minSpectrumLevel
uint8 *	maxSpectrumLevel
uint8	spectrumDCLevel
float	avgSpectrumDCLevel
float	spectrumDCLevelSum
sint8 *	minWaveformVal
sint8 *	maxWaveformVal
sint8	minWaveformValMono
sint8	maxWaveformValMono
uint32 *	waveformValSum
uint32 *	peakWaveformValSum
uint32 *	prevWaveformValSum
uint32 *	avgWaveformValSum
uint32 *	avgWaveformValSumCounter
bool	isBeatImpulse
RMSValue	rmsBuffer [2000]
uint16	currRMSValue
uint8	currRecordedBeat
BeatGuess *	beatsRecordedInBeatAnalyseTimeFrame
Static Private Attributes
static VisualAudioLab *	theVisualAudioLab = NULL
static uint16	maxNumberOfAudioDataChannels = 0
static uint32	numberOfAudioWaveformDataEntries = 0
static uint32	numberOfAudioSpectrumDataEntries = 0
static const uint8	beatTimeTolerance = 25
static const uint16	beatThreshold = 300
static const uint16	beatAnalyseTimeFrame = 10000
static const uint16	maximumBeatInterval = 2000
static const uint16	numberOfMillisecondsOfRMSBuffer = 3000
static const uint16	numberOfRMSBufferEntries = 2000
static const uint16	maxNumberOfWaveformShapeHistory = 1400
static const uint16	maxNumberOfMusicDataHistory = 40
static const uint16	tappingBufferLength = 4096
static const uint16	maxNumberOfBeatHistogramBins = 100
static const uint16	maxNumberOfBeatsRecordedInAnalyseTimeframe = 200

Detailed Description

A collection of routines dealing with processing, analyzing and interpretation of audio data.

Constructor & Destructor Documentation

VisualAudioLab::VisualAudioLab ( ) [private]

The constructor. VisualAudioLab is a singleton class. The constructor is private. New instance of class can only be created internally.

VisualAudioLab::~VisualAudioLab ( ) [private]

The destructor. VisualAudioLab is a singleton class. The destructor is private. Instance of class can only be destructed internally.

VizKit::VisualAudioLab::VisualAudioLab ( const VisualAudioLab & other ) [private]

Copy constructor.

Parameters:

other

Another VisualAudioLab.

Remarks:: Explicitely declared in private section and not implemented to enforce uniqueness of singleton pattern.

Member Function Documentation

void VisualAudioLab::addToBeatGapHistogram ( uint16 gapInMilliseconds ) [private]

Adds a value to beatGapHistogram.

Parameters:

gapInMilliseconds

The gap to previous beat detection in milliseconds.

void VisualAudioLab::addToBeatRecords ( void ) [private]

Adds a value to beatsRecordedInBeatAnalyseTimeFrame.

void VizKit::VisualAudioLab::addToWaveformShape	(	sint8	minWaveformPoint,
		sint8	maxWaveformPoint
	)			`[private]`

Adds the minimum and maximum waveform data value to the waveform shape.

Parameters:

	minWaveformPoint	The minimum waveform data value.
	maxWaveformPoint	The maximum waveform data value.

void VisualAudioLab::calcBeatConfidence ( void ) [private]

Calculates the confidence of the beat estimation.

void VisualAudioLab::checkForBeatImpulse ( void )

Checks for the beat impulse and sends a notification in case a beat impulse is detected.

void VisualAudioLab::dispose ( void ) [static]

Disposes the VisualAudiolab.

const uint32 *const VisualAudioLab::getBeatHistogram ( void )

Returns a pointer to the histogram of the gaps between detected beat events.

Returns:: A pointer to the histogram of the gaps between detected beat events.

uint8 VisualAudioLab::getBeatMeter ( void )

Answers the question whether the current timestamp suggests a beat impulse.

Returns:: 1 if the current timestamp suggests a beat impulse, 0 if not.

uint32 VisualAudioLab::getBestBeatMSInterval ( void ) [private]

Returns the best guess for the beat interval in milliseconds. The best guess for the beat interval in milliseconds.

sint16 VisualAudioLab::getCurrMusicDataHistory ( void )

Returns the current music data history.

Returns:: The current music data history.

uint32 VisualAudioLab::getCurrTimestampIDOfRenderData ( void )

Returns the last processed timestampID of the kVisualPluginRenderMessage.

Returns:: The last processed timestampID of the kVisualPluginRenderMessage.

uint8 VisualAudioLab::getDCIntensity ( void )

Returns the DC intensity. The DC intensity is the intensity of the direct current.

Returns:: The DC intensity.

VisualAudioLab * VisualAudioLab::getInstance ( void ) [static]

Returns the VisualAudioLab. The VisualAudiolab is initialized if required. The VisualAudioLab is a singleton.

uint16 VisualAudioLab::getMaxNumberOfMusicDataHistories ( void )

Returns the maximum number of histories in waveform data.

Returns:: The maximum number of histories in waveform data.

uint16 VisualAudioLab::getMaxNumberOfWaveformShapeHistory ( void )

Returns the maximum history number.

Returns:: The maximum history number.

uint8 VisualAudioLab::getMonoWaveformDataAtIndex ( const uint16 index )

Returns the waveform data value of a specific index position.

Parameters:

index

The index of the requested waveform data.

Returns:: The mono waveform data at a specific index.

uint8 VisualAudioLab::getMonoWaveformDataAtIndexWithHistoryNum	(	const uint16	index,
		const uint16	historyNum
	)

Returns the mono waveform data of a specific history at a specific index.

Parameters:

	index	The index of the requested waveform data.
	historyNum	The history of the requested waveform data.

Returns:: The mono waveform data of a specific history at a specific index.

uint32 VizKit::VisualAudioLab::getNumberOfAudioSpectrumDataEntries ( void )

Returns the number of audio spectrum data entries.

Returns:: The number of audio spectrum data entries.

uint16 VisualAudioLab::getNumberOfDataChannels ( void )

Returns the number of data channels.

Returns:: The number of data channels.

uint32 VisualAudioLab::getNumberOfSpectrumEntries ( void )

Returns the number of spectrum data entries.

Returns:: The number of spectrum data entries.

uint32 VisualAudioLab::getNumberOfWaveformEntries ( void )

Returns the number of waveform data entries.

Returns:: The number of waveform data entries.

sint16 VisualAudioLab::getPrevMusicDataHistory ( void )

Returns the previous music data history. The previous music data history is the one that was current before the one that is now current.

Returns:: The previous music data history.

uint32 VisualAudioLab::getRemainingTimeOfCurrentTrack ( void )

Returns the remaining time of the currently playing audio track measured in milliseconds.

Returns:: The remaining time of the currently playing audio track measured in milliseconds.

uint8 VisualAudioLab::getRMSIntensity ( void )

Returns the RMS (root-mean-square) intensity. The RMS intensity is the computed root-mean-square value.

Returns:: The RMS intensity.

const uint8 ***const VisualAudioLab::getSpectrumDataArray ( void )

Returns a pointer to the spectrum data array.

Returns:: A pointer to the spectrum data array.

uint32 VisualAudioLab::getTotalTimeOfCurrentTrack ( void )

Returns the total time of the currently playing audio track measured in milliseconds.

Returns:: The total time of the currently playing audio track measured in milliseconds.

const sint16 **const VisualAudioLab::getWaveformDataMonoArray ( void )

Returns a pointer to the mono waveform data array. The mono waveform data consists of the averaged values of the waveform data of all available channels.

Returns:: A pointer to the mono waveform data array.

uint8 VisualAudioLab::getWaveformDataOfChannelAtIndex	(	const uint16	channel,
		const uint16	index
	)

Returns the single waveform data of a specific channel at a specific index position.

Parameters:

	channel	The channel.
	index	The index of the waveform data.

Returns:: The single waveform data of a specific channel at a specific index position.

uint8 VisualAudioLab::getWaveformDataOfChannelAtIndexWithHistoryNum	(	const uint16	channel,
		const uint16	index,
		const uint16	historyNum
	)

Returns the waveform data of a specific channel of a specific history at a specific index.

Parameters:

	channel	The cannel of the requested waveform data.
	index	The index of the requested waveform data.
	historyNum	The history of the requested waveform data.

Returns:: The waveform data of a specific channel of a specific history at a specific index.

const sint8* const VizKit::VisualAudioLab::getWaveformShapeArray ( void )

Returns a pointer to the waveform shape array.

Returns:: A pointer to the waveform shape array.

void VisualAudioLab::HannWindow	(	const int	N,
		double	TimeSamples[]
	)

Processes the sample data with a Hann window.

Parameters:

	N	The number of samples.
	TimeSamples	The sample data.

void VisualAudioLab::incrementMusicDataHistory ( void ) [private]

Increments the current history number of music data. Music data is stored for a number of histories.

void VisualAudioLab::init ( void ) [private]

Allocates and initializes the buffers of the VisualAudioLab.

uint8 VisualAudioLab::isBeatMeter ( uint32 elapsedMSSinceStartOfTrack ) [private]

Parameters:

elapsedMSSinceStartOfTrack

The number of milliseconds elapsed since start of audio track.

Returns:: 1 if time is in frame of beat meter, 0 if not.

VisualAudioLab& VizKit::VisualAudioLab::operator= ( const VisualAudioLab & other ) [private]

Assignment operator.

Remarks:: Explicitely declared in private section and not implemented to enforce uniqueness of singleton pattern.

void VisualAudioLab::processAudioData	(	uint8	numWaveformChannels,
		uint16	numWaveformEntries,
		const uint8 *const	currWaveformData,
		uint8	numSpectrumChannels,
		uint16	numSpectrumEntries,
		const uint8 *const	currSpectrumData
	)

Processes the audio data chunks. With each RenderMessage iTunes delivers waveform data and spectrum data. The spectrum data is a fft (Fast Fourier Transform) of the waveform data.

Parameters:

	numWaveformChannels	The number of waveform data channels.
	numWaveformEntries	The number of waveform data entries per channel.
	currWaveformData	A pointer to the waveform data.
	numSpectrumChannels	The number of spectrum data channels.
	numSpectrumEntries	The number of spectrum data entries per channel.
	currSpectrumData	A pointer to the spectrum data.

void VisualAudioLab::processSpectrumData	(	const uint8	numSpectrumChannels,
		const uint16	numSpectrumEntries,
		const uint8 *const	currSpectrumData
	)			`[private]`

Processes the spectrum data.

Parameters:

	numSpectrumChannels	The number of spectrum data channels (e.g. two for stereo sound)..
	numSpectrumEntries	The number of data points per channel.
	currSpectrumData	A pointer to the current spectrum data.

void VisualAudioLab::processWaveformData	(	uint8	numWaveformChannels,
		uint16	numWaveformEntries,
		const uint8 *const	currWaveformData
	)			`[private]`

Processes the waveform data.

Parameters:

	numWaveformChannels	The number of waveform data channels (e.g. two for stereo sound).
	numWaveformEntries	The number of data points per channel.
	currWaveformData	A pointer to the current waveform data.

bool VisualAudioLab::remainingTimeOfCurrentTrackIsKnown ( void )

Answers the question whether the remaining time of the current track is known. Streamed audio has no info about remaining time of current track.

Returns:: True if the remaining time of the current track is known, false if not.

void VisualAudioLab::resetBeatGapHistogram ( void ) [private]

Resets the beatGapHistogram.

void VisualAudioLab::resetData ( void )

Resets the stored values of the VisualAudioLab. The VisualAudioLab stores analyzed values of an audio track. Typically the values are resetted when a new track starts playing.

void VisualAudioLab::setCurrTimestampIDOfRenderData ( const uint32 timestampID )

Sets the last processed timestampID of the kVisualPluginRenderMessage.

Parameters:

timestampID

The last processed timestampID of the kVisualPluginRenderMessage.

void VisualAudioLab::setMaxNumberOfAudioDataChannels ( uint16 aNumberOfMaxAudioDataChannels ) [static]

Sets the maximum number of audio data channels (2 channels means stereo).

Parameters:

aNumberOfMaxAudioDataChannels

The maximum number of audio data channels.

void VisualAudioLab::setNumberOfAudioSpectrumDataEntries ( uint32 aNumberOfAudioSpectrumDataEntries ) [static]

Sets the number of audio spectrum data entries.

Parameters:

aNumberOfAudioSpectrumDataEntries

The number of audio spectrum data entries.

void VisualAudioLab::setNumberOfAudioWaveformDataEntries ( uint32 aNumberOfAudioWaveformDataEntries ) [static]

Sets the number of audio waveform data entries.

Parameters:

aNumberOfAudioWaveformDataEntries

The number of audio waveform data entries.

void VisualAudioLab::setStartTimeOfCurrentTrack ( const uint32 startTimeInMS )

Stores the start time of the current track.

Parameters:

startTimeInMS

The start time of the currently playing audio track measured in milliseconds.

void VisualAudioLab::setStopTimeOfCurrentTrack ( const uint32 stopTimeInMS )

Stores the stop time of the current track.

Parameters:

stopTimeInMS

The stop time of the currently playing audio track measured in milliseconds.

void VisualAudioLab::setTotalTimeOfCurrentTrack ( const uint32 totalTimeInMS )

Stores the total time of the current track.

Parameters:

totalTimeInMS

The total time of the currently playing audio track measured in milliseconds.

void VisualAudioLab::storeBeatImpulse ( bool beatImpulse ) [private]

Stores the beat impulse.

Parameters:

beatImpulse

True if the current waveform data indicates a beat impulse, false if not.

Member Data Documentation

double* VizKit::VisualAudioLab::amplitudeEnvelope [private]

The amplitude envelope array.

float VizKit::VisualAudioLab::avgSpectrumDCLevel [private]

The average spectrum DC level.

uint32* VizKit::VisualAudioLab::avgWaveformValSum [private]

The average value of the sum of the waveform data values.

uint32* VizKit::VisualAudioLab::avgWaveformValSumCounter [private]

The counter for the calculation o the average value of the sum of the waveform data values.

const uint16 VisualAudioLab::beatAnalyseTimeFrame = 10000 [static, private]

The time frame in which beats are recorded and analysed. Measured in milliseconds.

uint32* VizKit::VisualAudioLab::beatGapHistogram [private]

A histogram of the gaps between detected beat events.

BeatGuess* VizKit::VisualAudioLab::beatsRecordedInBeatAnalyseTimeFrame [private]

Array in which the detected beats are stored with their elapsed milliseconds timestamp since start of track. Ringbuffer.

const uint16 VisualAudioLab::beatThreshold = 300 [static, private]

The threshold after which we are free to detect a new beat. Measured in milliseconds.

uint32 VizKit::VisualAudioLab::beatTimeDeltaInMS [private]

The delta between beats.

const uint8 VisualAudioLab::beatTimeTolerance = 25 [static, private]

The smallest time a beat is considered to be the same. Measured in milliseconds.

sint16 VizKit::VisualAudioLab::currMusicDataHistory [private]

The current history number.

uint8 VizKit::VisualAudioLab::currRecordedBeat [private]

The current index of array beatsRecordedInBeatAnalyseTimeFrame.

uint16 VizKit::VisualAudioLab::currRMSValue [private]

The current index of array rmsBuffer.

uint32 VizKit::VisualAudioLab::currTimestampIDOfRenderData [private]

The last processed timestampID of the kVisualPluginRenderMessage.

uint32 VizKit::VisualAudioLab::elapsedTimeOfTrack [private]

The accumulated play time of the current audio track measured in milliseconds.

bool VizKit::VisualAudioLab::isBeatImpulse [private]

1 if the current waveform data indicates a beat impulse, 0 if not.

const uint16 VisualAudioLab::maximumBeatInterval = 2000 [static, private]

The maximum beat interval. Measured in milliseconds.

uint16 VisualAudioLab::maxNumberOfAudioDataChannels = 0 [static, private]

The maximum number of audio data channels (2 channels means stereo).

const uint16 VisualAudioLab::maxNumberOfBeatHistogramBins = 100 [static, private]

const uint16 VisualAudioLab::maxNumberOfBeatsRecordedInAnalyseTimeframe = 200 [static, private]

const uint16 VisualAudioLab::maxNumberOfMusicDataHistory = 40 [static, private]

const uint16 VisualAudioLab::maxNumberOfWaveformShapeHistory = 1400 [static, private]

uint8* VizKit::VisualAudioLab::maxSpectrumLevel [private]

The maximum spectrum level. 0-128.

sint8* VizKit::VisualAudioLab::maxWaveformVal [private]

The maximum waveform data value. 0-255. -128 ...127.

sint8 VizKit::VisualAudioLab::maxWaveformValMono [private]

The maximum mono waveform data value.

sint32* VizKit::VisualAudioLab::mean [private]

The mean values.

uint8* VizKit::VisualAudioLab::minSpectrumLevel [private]

The minimum spectrum level. 0-128.

sint8* VizKit::VisualAudioLab::minWaveformVal [private]

The minimum waveform data value. 0-255. -128 ...127.

sint8 VizKit::VisualAudioLab::minWaveformValMono [private]

The minimum mono waveform data value.

uint32 VisualAudioLab::numberOfAudioSpectrumDataEntries = 0 [static, private]

The number of audio spectrum data entries.

uint32 VisualAudioLab::numberOfAudioWaveformDataEntries = 0 [static, private]

The number of audio waveform data entries.

const uint16 VisualAudioLab::numberOfMillisecondsOfRMSBuffer = 3000 [static, private]

The number of milliseconds rms values are collected.

sint8 VizKit::VisualAudioLab::numberOfMusicDataHistoryInt [private]

The number of music data history.

const uint16 VisualAudioLab::numberOfRMSBufferEntries = 2000 [static, private]

The number of records in rmsBuffer. Must be greater than: Audio sample rate (44100) / kVisualNumWaveformEntries * (numberOfMillisecondsOfRMSBuffer / 1000).

uint32* VizKit::VisualAudioLab::peakWaveformValSum [private]

The peak values of the sum of the waveform data values.

uint32* VizKit::VisualAudioLab::prevWaveformValSum [private]

The previous sum of the waveform data values.

double** VizKit::VisualAudioLab::rms [private]

The rms values.

RMSValue VizKit::VisualAudioLab::rmsBuffer[2000] [private]

Array containg rms mono values for the last numberOfMillisecondsOfRMSBuffer milliseconds. Ringbuffer. RMSValues with ((currentMSSinceStartOfTrack - timeInMillisecondsSinceStartOfTrack) > numberOfMillisecondsOfRMSBuffer) are discarded.

double* VizKit::VisualAudioLab::rmsMono [private]

The mono rms values.

double VizKit::VisualAudioLab::rmsMonoAvg [private]

The average rms value.

double VizKit::VisualAudioLab::rmsMonoMax [private]

The maximum mono rms value. Timeframe numberOfMillisecondsOfRMSBuffer.

uint8*** VizKit::VisualAudioLab::spectrumData [private]

The spectrum data array. The spectrum data array is 3-dimensional with data values, channels and history.

uint8 VizKit::VisualAudioLab::spectrumDCLevel [private]

The spectrum DC level. 0-256 (?). Direct Current of FFT (mono).

float VizKit::VisualAudioLab::spectrumDCLevelSum [private]

The sum of the spectrum DC level. sum of data (for calc of avg).