CUGL 2.1
Cornell University Game Library
Public Member Functions | Static Public Member Functions | List of all members
cugl::audio::AudioSynchronizer Class Reference

#include <CUAudioSynchronizer.h>

Inheritance diagram for cugl::audio::AudioSynchronizer:
cugl::audio::AudioNode

Public Member Functions

 AudioSynchronizer ()
 
 ~AudioSynchronizer ()
 
virtual bool init () override
 
virtual bool init (Uint8 channels, Uint32 rate) override
 
virtual void dispose () override
 
double getOverhead () const
 
void setOverhead (double overhead)
 
double getJitter () const
 
void clearJitter ()
 
bool onBeat ()
 
bool attach (const std::shared_ptr< AudioNode > &node, double bpm=0.0)
 
std::shared_ptr< AudioNodedetach ()
 
std::shared_ptr< AudioNodegetInput () const
 
virtual bool completed () override
 
virtual Uint32 read (float *buffer, Uint32 frames) override
 
virtual bool mark () override
 
virtual bool unmark () override
 
virtual bool reset () override
 
virtual Sint64 advance (Uint32 frames) override
 
virtual Sint64 getPosition () const override
 
virtual Sint64 setPosition (Uint32 position) override
 
virtual double getElapsed () const override
 
virtual double setElapsed (double time) override
 
virtual double getRemaining () const override
 
virtual double setRemaining (double time) override
 
- Public Member Functions inherited from cugl::audio::AudioNode
 AudioNode ()
 
virtual ~AudioNode ()
 
Uint8 getChannels () const
 
Uint32 getRate () const
 
float getGain ()
 
virtual void setGain (float gain)
 
const std::string & getClassName () const
 
const std::string & getName () const
 
void setName (const std::string name)
 
Sint32 getTag () const
 
void setTag (Sint32 tag)
 
virtual std::string toString (bool verbose=false) const
 
 operator std::string () const
 
Callback getCallback ()
 
void setCallback (Callback callback)
 
virtual bool isPaused ()
 
virtual bool pause ()
 
virtual bool resume ()
 

Static Public Member Functions

static std::shared_ptr< AudioSynchronizeralloc ()
 
static std::shared_ptr< AudioSynchronizeralloc (Uint8 channels, Uint32 rate)
 

Additional Inherited Members

- Public Types inherited from cugl::audio::AudioNode
enum  Action : int {
  COMPLETE = 0, INTERRUPT = 1, FADE_OUT = 2, FADE_IN = 3,
  FADE_DIP = 4, LOOPBACK = 5
}
 
typedef std::function< void(const std::shared_ptr< AudioNode > &node, Action type)> Callback
 
- Static Public Attributes inherited from cugl::audio::AudioNode
const static Uint32 DEFAULT_CHANNELS
 
const static Uint32 DEFAULT_SAMPLING
 
- Protected Member Functions inherited from cugl::audio::AudioNode
void notify (const std::shared_ptr< AudioNode > &node, Action action)
 
- Protected Attributes inherited from cugl::audio::AudioNode
Uint8 _channels
 
Uint32 _sampling
 
bool _booted
 
std::atomic< float > _ndgain
 
std::atomic< bool > _paused
 
std::atomic< bool > _polling
 
Callback _callback
 
std::atomic< bool > _calling
 
Sint32 _tag
 
std::string _localname
 
std::string _classname
 
size_t _hashOfName
 

Detailed Description

A class providing visual synchronization for an audio node.

Because of variable latency issues on mobile platforms, synchronization for rhythm games is always difficult. This EXPERIMENTAL class is attempt to resolve this issue.

To use this class, attach a node with three channels. The first two channels are stereo sound while the third channel represents the "beat". Any non-zero signal in this channel represents a beat window.

WARNING: This class is largely untested. Use at your own risk.

This class does not support any actions for the AudioNode#setCallback.

Constructor & Destructor Documentation

◆ AudioSynchronizer()

cugl::audio::AudioSynchronizer::AudioSynchronizer ( )

Creates a degenerate audio synchronizer

The node has no channels, so read options will do nothing. The node must be initialized to be used.

NEVER USE A CONSTRUCTOR WITH NEW. If you want to allocate a graph node on the heap, use one of the static constructors instead.

◆ ~AudioSynchronizer()

cugl::audio::AudioSynchronizer::~AudioSynchronizer ( )
inline

Deletes the audio synchronizer, disposing of all resources

Member Function Documentation

◆ advance()

virtual Sint64 cugl::audio::AudioSynchronizer::advance ( Uint32  frames)
overridevirtual

Advances the stream by the given number of frames.

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

This method only advances the read position, it does not actually read data into a buffer. This method is generally not supported for nodes with real-time input like AudioInput.

Parameters
framesThe number of frames to advace
Returns
the actual number of frames advanced; -1 if not supported

Reimplemented from cugl::audio::AudioNode.

◆ alloc() [1/2]

static std::shared_ptr<AudioSynchronizer> cugl::audio::AudioSynchronizer::alloc ( )
inlinestatic

Returns a newly allocated synchronizer with default stereo settings

The number of output channels is two, for stereo output. Input nodes must either match this (for no carrier signal) or have one additional channel. The sample rate is the modern standard of 48000 HZ.

Returns
a newly allocated synchronizer with default stereo settings

◆ alloc() [2/2]

static std::shared_ptr<AudioSynchronizer> cugl::audio::AudioSynchronizer::alloc ( Uint8  channels,
Uint32  rate 
)
inlinestatic

Returns a newly allocated synchronizer with the given number of channels and sample rate

The channels specifies the number of output channels. Input nodes must either match this (for no carrier signal) or have one additional channel.

Parameters
channelsThe number of audio channels
rateThe sample rate (frequency) in HZ
Returns
a newly allocated synchronizer with the given number of channels and sample rate

◆ attach()

bool cugl::audio::AudioSynchronizer::attach ( const std::shared_ptr< AudioNode > &  node,
double  bpm = 0.0 
)

Attaches an audio node to this synchronizer.

The audio node must agree with the sample rate of this synchronizer. If it has a carrier signal, then it should have one more channel than this node, with the extra channel delivering the signal. If it does not have a carrier signal, it must agree with the number of channels of this node.

The optional bpm (beats-per-minute) argument is only applicable if the node does not have a carrier signal. In that case, it will use the timestamps to guess at the synchronization information. If the bpm value is not positive, it will not attempt to synchronize.

Parameters
nodeThe audio node to synchronize
bpmThe beats-per-minute if a carrier signal is missing
Returns
true if the attachment was successful

◆ clearJitter()

void cugl::audio::AudioSynchronizer::clearJitter ( )

Clears the jitter readings to reset the calculations

◆ completed()

virtual bool cugl::audio::AudioSynchronizer::completed ( )
overridevirtual

Returns true if this audio node has no more data.

An audio node is typically completed if it return 0 (no frames read) on subsequent calls to read(). However, for infinite-running audio threads, it is possible for this method to return true even when data can still be read; in that case the node is notifying that it should be shut down.

Returns
true if this audio node has no more data.

Reimplemented from cugl::audio::AudioNode.

◆ detach()

std::shared_ptr<AudioNode> cugl::audio::AudioSynchronizer::detach ( )

Detaches an audio node from this synchronizer.

If the method succeeds, it returns the audio node that was removed.

Returns
The audio node to detach (or null if failed)

◆ dispose()

virtual void cugl::audio::AudioSynchronizer::dispose ( )
overridevirtual

Disposes any resources allocated for this synchronizer

The state of the node is reset to that of an uninitialized constructor. Unlike the destructor, this method allows the node to be reinitialized.

Reimplemented from cugl::audio::AudioNode.

◆ getElapsed()

virtual double cugl::audio::AudioSynchronizer::getElapsed ( ) const
overridevirtual

Returns the elapsed time in seconds.

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

In some nodes like AudioInput, this method is only supported if mark() is set. In that case, the times will be the number of seconds since the mark. Other nodes like AudioPlayer measure from the start of the stream.

Returns
the elapsed time in seconds.

Reimplemented from cugl::audio::AudioNode.

◆ getInput()

std::shared_ptr<AudioNode> cugl::audio::AudioSynchronizer::getInput ( ) const
inline

Returns the input node of this synchronizer.

Returns
the input node of this synchronizer.

◆ getJitter()

double cugl::audio::AudioSynchronizer::getJitter ( ) const
inline

Returns the currently observed jitter

Returns -1 if there is no jitter so far

◆ getOverhead()

double cugl::audio::AudioSynchronizer::getOverhead ( ) const
inline

Returns the (projected) overhead of reading the audio graph

Returns
the (projected) overhead of reading the audio graph

◆ getPosition()

virtual Sint64 cugl::audio::AudioSynchronizer::getPosition ( ) const
overridevirtual

Returns the current frame position of this audio node

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

In some nodes like AudioInput, this method is only supported if mark() is set. In that case, the position will be the number of frames since the mark. Other nodes like AudioPlayer measure from the start of the stream.

Returns
the current frame position of this audio node.

Reimplemented from cugl::audio::AudioNode.

◆ getRemaining()

virtual double cugl::audio::AudioSynchronizer::getRemaining ( ) const
overridevirtual

Returns the remaining time in seconds.

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

In some nodes like AudioInput, this method is only supported if setRemaining() has been called. In that case, the node will be marked as completed after the given number of seconds. This may or may not actually move the read head. For example, in AudioPlayer it will skip to the end of the sample. However, in AudioInput it will simply time out after the given time.

Returns
the remaining time in seconds.

Reimplemented from cugl::audio::AudioNode.

◆ init() [1/2]

virtual bool cugl::audio::AudioSynchronizer::init ( )
overridevirtual

Initializes the synchronizr with default stereo settings

The number of output channels is two, for stereo output. Input nodes must either match this (for no carrier signal) or have one additional channel. The sample rate is the modern standard of 48000 HZ.

Returns
true if initialization was successful

Reimplemented from cugl::audio::AudioNode.

◆ init() [2/2]

virtual bool cugl::audio::AudioSynchronizer::init ( Uint8  channels,
Uint32  rate 
)
overridevirtual

Initializes the synchronizer with the given number of channels and sample rate

The channels specifies the number of output channels. Input nodes must either match this (for no carrier signal) or have one additional channel.

Parameters
channelsThe number of audio channels
rateThe sample rate (frequency) in HZ
Returns
true if initialization was successful

Reimplemented from cugl::audio::AudioNode.

◆ mark()

virtual bool cugl::audio::AudioSynchronizer::mark ( )
overridevirtual

Marks the current read position in the audio steam.

DELEGATED METHOD: This method delegates its call to the input node. It returns false if there is no input node or if this method is unsupported in that node

This method is typically used by reset() to determine where to restore the read position. For some nodes (like AudioInput), this method may start recording data to a buffer, which will continue until reset() is called.

It is possible for reset() to be supported even if this method is not.

Returns
true if the read position was marked.

Reimplemented from cugl::audio::AudioNode.

◆ onBeat()

bool cugl::audio::AudioSynchronizer::onBeat ( )

Returns true if the music is on the beat

Returns
true if the music is on the beat

◆ read()

virtual Uint32 cugl::audio::AudioSynchronizer::read ( float *  buffer,
Uint32  frames 
)
overridevirtual

Reads up to the specified number of frames into the given buffer

AUDIO THREAD ONLY: Users should never access this method directly. The only exception is when the user needs to create a custom subclass of this AudioOutput.

The buffer should have enough room to store frames * channels elements. The channels are interleaved into the output buffer.

This method will always forward the read position.

Parameters
bufferThe read buffer to store the results
framesThe maximum number of frames to read
Returns
the actual number of frames read

Reimplemented from cugl::audio::AudioNode.

◆ reset()

virtual bool cugl::audio::AudioSynchronizer::reset ( )
overridevirtual

Resets the read position to the marked position of the audio stream.

DELEGATED METHOD: This method delegates its call to the input node. It returns false if there is no input node or if this method is unsupported in that node

When no mark() is set, the result of this method is node dependent. Some nodes (such as AudioPlayer) will reset to the beginning of the stream, while others (like AudioInput) only support a rest when a mark is set. Pay attention to the return value of this method to see if the call is successful.

Returns
true if the read position was moved.

Reimplemented from cugl::audio::AudioNode.

◆ setElapsed()

virtual double cugl::audio::AudioSynchronizer::setElapsed ( double  time)
overridevirtual

Sets the read position to the elapsed time in seconds.

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

In some nodes like AudioInput, this method is only supported if mark() is set. In that case, the new time will be meaured from the mark. Other nodes like AudioPlayer measure from the start of the stream.

Parameters
timeThe elapsed time in seconds.
Returns
the new elapsed time in seconds.

Reimplemented from cugl::audio::AudioNode.

◆ setOverhead()

void cugl::audio::AudioSynchronizer::setOverhead ( double  overhead)

Sets the projected overhead of reading the audio graph

Parameters
overheadThe projected overhead of reading the audio graph

◆ setPosition()

virtual Sint64 cugl::audio::AudioSynchronizer::setPosition ( Uint32  position)
overridevirtual

Sets the current frame position of this audio node.

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

In some nodes like AudioInput, this method is only supported if mark() is set. In that case, the position will be the number of frames since the mark. Other nodes like AudioPlayer measure from the start of the stream.

Parameters
positionthe current frame position of this audio node.
Returns
the new frame position of this audio node.

Reimplemented from cugl::audio::AudioNode.

◆ setRemaining()

virtual double cugl::audio::AudioSynchronizer::setRemaining ( double  time)
overridevirtual

Sets the remaining time in seconds.

DELEGATED METHOD: This method delegates its call to the input node. It returns -1 if there is no input node or if this method is unsupported in that node

If this method is supported, then the node will be marked as completed after the given number of seconds. This may or may not actually move the read head. For example, in AudioPlayer it will skip to the end of the sample. However, in AudioInput it will simply time out after the given time.

Parameters
timeThe remaining time in seconds.
Returns
the new remaining time in seconds.

Reimplemented from cugl::audio::AudioNode.

◆ unmark()

virtual bool cugl::audio::AudioSynchronizer::unmark ( )
overridevirtual

Clears the current marked position.

DELEGATED METHOD: This method delegates its call to the input node. It returns false if there is no input node or if this method is unsupported in that node

If the method mark() started recording to a buffer (such as with AudioInput), this method will stop recording and release the buffer. When the mark is cleared, reset() may or may not work depending upon the specific node.

Returns
true if the read position was marked.

Reimplemented from cugl::audio::AudioNode.


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