A simple Arduino API for the libhelix MP3 decoder. The data is provided with the help of write() calls. The decoded result is available either via a callback method or via an output stream. More...

#include <MP3DecoderHelix.h>

Inheritance diagram for libhelix::MP3DecoderHelix:

Public Member Functions
	MP3DecoderHelix (Print &output, MP3Type mp3Type=MP3Normal)

	MP3DecoderHelix (MP3DataCallback dataCallback, MP3Type mp3Type=MP3Normal)

	MP3DecoderHelix (MP3Type mp3Type)

void	setInfoCallback (MP3InfoCallback cb, void *caller=nullptr)

void	setDataCallback (MP3DataCallback cb)

MP3FrameInfo	audioInfo ()
	Provides the last available MP3FrameInfo.

void	end () override
	Releases the reserved memory.

size_t	maxFrameSize () override
	determines the frame buffer size that will be allocated

size_t	maxPCMSize () override
	Determines the pcm buffer size that will be allocated.

void	setOutput (Print &output)

virtual bool	begin ()
	Starts the processing.

virtual size_t	write (const void *in_ptr, size_t in_size)
	decodes the next segments from the input. The data can be provided in one short or in small incremental pieces. It is suggested to be called in the Arduino Loop. If the provided data does not fit into the buffer it is split up into small pieces that fit

	operator bool ()
	returns true if active

virtual void	setDelay (int delayMs)
	Defines the delay that is added at each segment.

uint64_t	timeOfLastWrite ()
	Provides the timestamp in ms of last write.

uint64_t	timeOfLastResult ()
	Provides the timestamp in ms of last decoded result.

void	flush ()
	Decode open packets.

void	setMaxFrameSize (size_t len)
	Define your optimized maximum frame size in bytes.

void	setMaxPCMSize (size_t len)
	Define your optimized maximum pcm buffer size in bytes.

void	setRaw (bool)
	Obsolete!

Protected Member Functions
virtual bool	allocateDecoder () override
	Allocate the decoder.

int	findSynchWord (int offset=0) override

int	decode () override
	decods the data and removes the decoded frame from the buffer

void	provideResult (MP3FrameInfo &info)

bool	presync ()
	make sure that we start with a valid sync: remove ID3 data

bool	resynch (int rc)

bool	removeInvalidData (int pos)

virtual size_t	writeChunk (const void *in_ptr, size_t in_size)

virtual int	minFrameBufferSize ()

Protected Attributes
HMP3Decoder	decoder = nullptr

MP3DataCallback	pcmCallback = nullptr

MP3InfoCallback	infoCallback = nullptr

MP3Type	mp3_type

MP3FrameInfo	mp3FrameInfo

void *	p_caller_ref = nullptr

void *	p_caller_data = nullptr

bool	active = false

bool	is_raw = false

Vector< uint8_t >	pcm_buffer {0}

SingleBuffer< uint8_t >	frame_buffer {0}

size_t	max_frame_size = 0

size_t	max_pcm_size = 0

size_t	frame_counter = 0

int	delay_ms = -1

uint64_t	time_last_write = 0

uint64_t	time_last_result = 0

Print *	out = nullptr

Detailed Description

A simple Arduino API for the libhelix MP3 decoder. The data is provided with the help of write() calls. The decoded result is available either via a callback method or via an output stream.

Author: Phil Schatzmann

Copyright: GPLv3

Member Function Documentation

◆ findSynchWord()

int libhelix::MP3DecoderHelix::findSynchWord ( int offset = 0 )

inlineoverrideprotectedvirtual

Finds the synch word in the available buffer data starting from the indicated offset

Implements libhelix::CommonHelix.

◆ removeInvalidData()

bool libhelix::CommonHelix::removeInvalidData ( int pos )

inlineprotectedinherited

removes invalid data not starting with a synch word.

Returns: Returns true if we still have data to be played

◆ resynch()

bool libhelix::CommonHelix::resynch ( int rc )

inlineprotectedinherited

advance on invalid data, returns true if we need to continue the processing

◆ writeChunk()

virtual size_t libhelix::CommonHelix::writeChunk	(	const void *	in_ptr,
		size_t	in_size
	)

inlineprotectedvirtualinherited

Prevent bug in underflow detection for AAC

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

src/MP3DecoderHelix.h

Public Member Functions