cugl::audio::MP3Decoder Class Reference

#include <CUMP3Decoder.h>

Inheritance diagram for cugl::audio::MP3Decoder:

Public Member Functions
	MP3Decoder ()
	~MP3Decoder ()
bool	init (const char *file) override
bool	init (const std::string &file) override
void	dispose () override
Sint32	pagein (float *buffer) override
void	setPage (Uint64 page) override
Public Member Functions inherited from cugl::audio::AudioDecoder
	AudioDecoder ()
	~AudioDecoder ()
double	getDuration () const
Uint32	getSampleRate () const
Uint64	getLength () const
Uint32	getChannels () const
std::string	getFile () const
Uint32	getPageSize () const
bool	ready ()
Uint64	getPage () const
Uint64	getPageCount () const
void	rewind ()
Sint32	decode (float *buffer)

Static Public Member Functions
static std::shared_ptr< AudioDecoder >	alloc (const char *file)
static std::shared_ptr< AudioDecoder >	alloc (const std::string &file)

Protected Attributes
Soundinputstream	_loader
Mpegtoraw *	_decoder
Sint16 *	_chunker
bool	_booted
Protected Attributes inherited from cugl::audio::AudioDecoder
Uint8	_channels
Uint32	_rate
Uint64	_frames
std::string	_file
Uint32	_pagesize
Uint64	_currpage
Uint64	_lastpage

Detailed Description

This class represents an MP3 decoder.

This decoder accesses the MP3 in the traditionally grouping of 1152 frames (we use frames to refer to samples, consistent with modern usage) per page. This class uses Jung woo-jae's free MPEG/WAVE Sound library to convert the individual pages into raw PCM data.

All channels are interleaved. Because of the age of the MPEG/WAVE Sound library, this decoder only supports stereo and mono MP3 files. In particular, it does not support MP3 surround.

A decoder is NOT thread safe. If a decoder is used by an audio thread, then it should not be accessed directly in the main thread, and vice versa.

Constructor & Destructor Documentation

MP3Decoder()

cugl::audio::MP3Decoder::MP3Decoder

(

)

Creates an initialized audio decoder

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

~MP3Decoder()

cugl::audio::MP3Decoder::~MP3Decoder

(

)

Deletes this decoder, disposing of all resources.

Member Function Documentation

alloc() [1/2]

static std::shared_ptr<AudioDecoder> cugl::audio::MP3Decoder::alloc ( const char *  file )

inlinestatic

Creates a newly allocated decoder for the given MP3 file.

This method will fail and return nullptr if the file is not a (stereo or mono) MP3 file.

Parameters

file	the source file for the decoder

Returns

a newly allocated decoder for the given MP3 file.

alloc() [2/2]

static std::shared_ptr<AudioDecoder> cugl::audio::MP3Decoder::alloc ( const std::string &  file )

static

Creates a newly allocated decoder for the given MP3 file.

This method will fail and return nullptr if the file is not a (stereo or mono) MP3 file.

Parameters

file	the source file for the decoder

Returns

a newly allocated decoder for the given MP3 file.

dispose()

void cugl::audio::MP3Decoder::dispose ( )

overridevirtual

Deletes the decoder resources and resets all attributes.

This will close the associated file. You must reinitialize the decoder to use it.

Implements cugl::audio::AudioDecoder.

init() [1/2]

bool cugl::audio::MP3Decoder::init ( const char *  file )

inlineoverridevirtual

Initializes a new decoder for the given MP3 file.

This method will fail if the file is not a (stereo or mono) MP3 file.

Parameters

file	the source file for the decoder

Returns

true if the decoder was initialized successfully

Reimplemented from cugl::audio::AudioDecoder.

init() [2/2]

bool cugl::audio::MP3Decoder::init ( const std::string &  file )

overridevirtual

Initializes a new decoder for the given MP3 file.

This method will fail if the file is not a (stereo or mono) MP3 file.

Parameters

file	the source file for the decoder

Returns

true if the decoder was initialized successfully

Implements cugl::audio::AudioDecoder.

pagein()

Sint32 cugl::audio::MP3Decoder::pagein ( float *  buffer )

overridevirtual

Reads a page of data into the provided buffer.

The buffer should be able to hold channels * page size many elements. The data is interpretted as floats and channels are all interleaved. If a full page is read, this method should return the page size. If it reads less, it will return the number of frames read. It will return -1 on a processing error.

Parameters

buffer

The buffer to store the audio data

Returns

the number of frames actually read (-1 on error).

Implements cugl::audio::AudioDecoder.

setPage()

void cugl::audio::MP3Decoder::setPage ( Uint64  page )

overridevirtual

Sets the current page of this decoder

This value is the next page to be read in with the pagein() command. If the page is greater than the total number of pages, it will be set just beyond the last page.

Parameters

page	The new page of this decoder

Implements cugl::audio::AudioDecoder.

Member Data Documentation

_booted

bool cugl::audio::MP3Decoder::_booted

protected

Whether this decoder was successfully booted

_chunker

Sint16* cugl::audio::MP3Decoder::_chunker

protected

The buffer for reading pages

_decoder

Mpegtoraw* cugl::audio::MP3Decoder::_decoder

protected

The MP3 decoder

_loader

Soundinputstream cugl::audio::MP3Decoder::_loader

protected

The loader for reading from a file

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

• include/cugl/audio/codecs/CUMP3Decoder.h