MidiFilePlayer Class Reference

Plays back MIDI files with configurable tempo. More...

#include <gin_midifileplayer.h>

Public Member Functions
	MidiFilePlayer ()=default
bool	load (const juce::File &file)
	Loads a MIDI file for playback.
void	setSampleRate (double sr)
	Sets the sample rate for playback timing.
void	setFallbackBpm (double bpm)
	Sets the fallback tempo to use when the MIDI file contains no tempo events.
void	play ()
	Starts playback from the current position.
void	stop ()
	Stops playback and sends note-off messages for any playing notes.
bool	isPlaying () const
	Returns true if currently playing.
double	getPlayheadPosition () const
	Returns the current playhead position in seconds.
void	setPlayheadPosition (double positionInSeconds)
	Sets the playhead position in seconds.
void	processBlock (int numSamples, juce::MidiBuffer &midiBuffer)
	Processes a block, filling the buffer with MIDI events.
double	getLengthInSeconds () const
	Returns the total length of the MIDI file in seconds.
void	setLooping (bool shouldLoop)
	Sets whether playback should loop.
bool	isLooping () const
	Returns true if looping is enabled.
const juce::MidiMessageSequence &	getSequence () const
	Returns the merged MIDI sequence for display purposes.
double	getLengthInTicks () const
	Returns the length in ticks (for display purposes).
bool	hasFileLoaded () const
	Returns true if a file has been loaded.
juce::File	getLoadedFile () const
	Returns the path of the currently loaded file, or empty if none.
void	clear ()
	Clears the currently loaded file.
juce::AudioPlayHead::PositionInfo	populatePositionInfo ()
	Returns position info for use with an AudioPlayHead.

Detailed Description

Plays back MIDI files with configurable tempo.

MidiFilePlayer loads a standard MIDI file and plays it back through processBlock calls, filling a MidiBuffer with the appropriate events for each audio block based on the current playhead position.

Thread Safety:

• load(), setFallbackBpm() should be called from the message thread
• processBlock() is called from the audio thread
• play(), stop(), setPlayheadPosition() can be called from either thread
• Getters are safe to call from any thread

Key Features:

• Load MIDI files from juce::File
• Respects MIDI file tempo events, with configurable fallback BPM
• Sample-accurate playback
• Play/stop controls with proper note-off handling
• Playhead position tracking

Usage:

MidiFilePlayer player;
player.load(midiFile);
player.setSampleRate(44100.0);
player.setFallbackBpm(120.0);  // Optional: only used if file has no tempo events
player.play();
 
// In audio callback
juce::MidiBuffer midiBuffer;
player.processBlock(numSamples, midiBuffer);

See also

juce::MidiFile, juce::MidiBuffer

Constructor & Destructor Documentation

MidiFilePlayer()

MidiFilePlayer::MidiFilePlayer ( )

default

Member Function Documentation

load()

bool MidiFilePlayer::load

(

const juce::File &

file

)

Loads a MIDI file for playback.

Call from the message thread only.

Parameters

file	The MIDI file to load

Returns

true if the file was loaded successfully

setSampleRate()

void MidiFilePlayer::setSampleRate

(

double

sr

)

Sets the sample rate for playback timing.

Parameters

sr	The sample rate in Hz

Referenced by StandaloneAudioProcessorPlayer::audioDeviceAboutToStart().

setFallbackBpm()

void MidiFilePlayer::setFallbackBpm

(

double

bpm

)

Sets the fallback tempo to use when the MIDI file contains no tempo events.

Call from the message thread only.

Parameters

bpm	The fallback tempo in beats per minute (default: 120)

Referenced by StandaloneAudioProcessorPlayer::StandaloneAudioProcessorPlayer().

play()

void MidiFilePlayer::play

(

)

Starts playback from the current position.

stop()

void MidiFilePlayer::stop

(

)

Stops playback and sends note-off messages for any playing notes.

isPlaying()

bool MidiFilePlayer::isPlaying

(

)

const

Returns true if currently playing.

getPlayheadPosition()

double MidiFilePlayer::getPlayheadPosition

(

)

const

Returns the current playhead position in seconds.

setPlayheadPosition()

void MidiFilePlayer::setPlayheadPosition

(

double

positionInSeconds

)

Sets the playhead position in seconds.

Parameters

positionInSeconds

The new playhead position

processBlock()

void MidiFilePlayer::processBlock	(	int	numSamples,
		juce::MidiBuffer &	midiBuffer
	)

Processes a block, filling the buffer with MIDI events.

Call from the audio thread only.

Parameters

numSamples	The number of samples in this block
midiBuffer	The buffer to fill with MIDI events

Referenced by StandaloneAudioProcessorPlayer::preProcessBlock().

getLengthInSeconds()

double MidiFilePlayer::getLengthInSeconds

(

)

const

Returns the total length of the MIDI file in seconds.

setLooping()

void MidiFilePlayer::setLooping

(

bool

shouldLoop

)

Sets whether playback should loop.

Referenced by StandaloneAudioProcessorPlayer::StandaloneAudioProcessorPlayer().

isLooping()

bool MidiFilePlayer::isLooping

(

)

const

Returns true if looping is enabled.

getSequence()

const juce::MidiMessageSequence & MidiFilePlayer::getSequence

(

)

const

Returns the merged MIDI sequence for display purposes.

Note: Only safe to call when not loading a new file.

getLengthInTicks()

double MidiFilePlayer::getLengthInTicks

(

)

const

Returns the length in ticks (for display purposes).

hasFileLoaded()

bool MidiFilePlayer::hasFileLoaded

(

)

const

Returns true if a file has been loaded.

Referenced by StandaloneAudioProcessorPlayer::preProcessBlock().

getLoadedFile()

juce::File MidiFilePlayer::getLoadedFile

(

)

const

Returns the path of the currently loaded file, or empty if none.

clear()

void MidiFilePlayer::clear

(

)

Clears the currently loaded file.

populatePositionInfo()

juce::AudioPlayHead::PositionInfo MidiFilePlayer::populatePositionInfo

(

)

Returns position info for use with an AudioPlayHead.

Call from the audio thread before processing.

Returns

PositionInfo populated with current playback state

Referenced by StandaloneAudioProcessorPlayer::preProcessBlock().

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

• gin_midifileplayer.h